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Perspective: Plant-Based Eating Pattern for Type 2 Diabetes Prevention and Treatment: Efficacy, Mechanisms, and Practical Considerations

  • Physicians Committee for Responsible Medicine


A plant-based eating pattern is associated with a reduced risk of developing type 2 diabetes and is highly effective in its treatment. Diets that emphasize whole grains, vegetables, fruits, and legumes and exclude animal products improve blood glucose concentrations, body weight, plasma lipid concentrations, and blood pressure and play an important role in reducing the risk of cardiovascular and microvascular complications. This article reviews scientific evidence on the effects of plant-based diets for the prevention and treatment of type 2 diabetes. The mechanisms by which plant-based diets improve body weight, insulin sensitivity, and β-cell function are described. Practical considerations including education, nutrition adequacy, and adjusting medications will enhance the success of patients who have diabetes.
Perspective: Plant-Based Eating Pattern for Type 2
Diabetes Prevention and Treatment: Ecacy,
Mechanisms, and Practical Considerations
Meghan A Jardine,1Hana Kahleova,2Susan M Levin,1Zeeshan Ali,1Caroline B Trapp,1and Neal D Barnard1
1Department of Nutrition, Physicians Committee for Responsible Medicine, Washington, DC, USA; and 2Department of Clinical Research, Physicians
Committee for Responsible Medicine, Washington, DC, USA
A plant-based eating pattern is associated with a reduced risk of developing type 2 diabetes and is highly effective in its treatment. Diets that
emphasize whole grains, vegetables, fruits, and legumes and exclude animal products improve blood glucose concentrations, body weight, plasma
lipid concentrations, and blood pressure and play an important role in reducing the risk of cardiovascular and microvascular complications. This
article reviews scientific evidence on the effects of plant-based diets for the prevention and treatment of type 2 diabetes. The mechanisms by which
plant-based diets improve body weight, insulin sensitivity, and β-cell function are described. Practical considerations including education, nutrition
adequacy, and adjusting medications will enhance the success of patients who have diabetes. Adv Nutr 2021;00:1–11.
Keywords: type 2 diabetes, plant-based nutrition, vegan diet, vegetarian diet, insulin resistance, diabetes, diet quality
Diabetes is a major worldwide health challenge aecting
individuals, families, communities, and governments. The
International Diabetes Federation estimated that 463 million
people (9.3% of the worldwide population) had diabetes
in 2019. Prevalence is expected to increase to 578 million
(10.4%) by 2030 (1).Globally,diabetescaused15million
deaths and contributed to 12% of health care expenditures
This article was funded by the Physicians Committee for Responsible Medicine, Washington
Author disclosures: MJ, HK, SL, ZA, and CT are employees of the Physicians Committee for
Responsible Medicine in Washington, DC, a nonprot organization providing education,
research, and medical services related to nutrition. NDB is an Adjunct Professor of Medicine at
the George Washington University School of Medicine. He serves without compensation as the
President of the Physicians Committee for Responsible Medicine and the Barnard Medical
Center in Washington, DC, nonprot organizations providingeducational, research, and
medical services related to nutrition. He writes books and articles and gives lectures related to
nutrition and health and has received royalties and honoraria from these sources.
Perspective articles allow authors to take a position on a topic of current major importance or
controversy in the eld of nutrition. As such, these articles could include statements based on
author opinions or point of view. Opinions expressed in Perspective articles are those of the
author and are not attributable to the funder(s) or the sponsor(s) or the publisher, Editor, or
Editorial Board of Advances in Nutrition. Individuals with dierent positions on the topic of a
Perspective are invited to submit their comments in the form of a Perspectives article or in a
Letter to the Editor.
Address correspondence to MAJ (e-mail:
Abbreviations used: AND, Academy of Nutrition and Dietetics; AHS-2, Adventist Health Study-2;
CVD, cardiovascular disease; DASH, Dietary Approaches for Stopping Hypertension; HbA1c,
glycated hemoglobin.
in 2015 (2). In addition to contributing to mortality,
macrovascular and microvascular complications of diabetes
greatly reduce quality of life.
Diabetes prevalence has increased in recent decades in
the context of signicant diet changes, including reduced
consumption of vegetables, fruits, and legumes, coupled with
increased consumption of animal-derived and processed
food products (3). A plant-based eating pattern is associated
with a signicantly lower prevalence of type 2 diabetes,
compared with nonvegetarian diets (4), and there is strong
evidence supporting the use of a plant-based eating pattern
in clinical practice for individuals with type 2 diabetes. The
American Association of Clinical Endocrinologists and the
American College of Endocrinology, as well as the American
College of Lifestyle Medicine, recommend a plant-based
eating pattern as a key component of lifestyle therapy for
patients with type 2 diabetes (5,6). Both the American
and Canadian Diabetes Associations include vegetarian
and vegan eating patterns among those shown to improve
glycemic control, body weight, and cardiovascular risk
factors (6,7). In addition to these organizations that support
a plant-based diet for diabetes, the USDA lists a Healthy
Vegetarian Dietary Pattern as an example of a healthy meal
plan in the 2020–2025 Dietary Guidelines for Americans
The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition. This is an Open Access article distributed under the terms of the Creative Commons
Attribution-NonCommercial License (, which permits non-commercial re-use, distribution, and reproduction in any medium, provided the
original work is properly cited. For commercial re-use, please contact Adv Nutr 2021;00:1–11; doi: 1
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The aim of this article is to provide an overview of the
evidence on the prevention and treatment of type 2 diabetes
with a plant-based eating pattern, the mechanistic actions
by which a plant-based eating pattern improves insulin
sensitivity and weight management, and considerations in
recommending a plant-based eating pattern. This article
includes earlier evidence that provides a foundation for
more current research. It also includes recent studies on
the mechanistic actions that demonstrate a plant-based diet
improves clinical outcomes for diabetes.
consisting mainly of grains, vegetables, legumes, fruits, nuts,
exclude meat. Subsets of vegetarian diets are lacto-ovo
vegetarian diets, which include dairy products and eggs,
and vegan diets, which exclude all animal products (9).
Hereafter in this article, the term “plant-based” will refer to
vegetarian (including lacto-ovo vegetarian and vegan) diets,
unless otherwise indicated.
A Plant-Based Eating Pattern Is Associated with
Reduced Risk of Type 2 Diabetes
Observational studies in widely diverse locales have iden-
tied large reductions in diabetes risk among populations
consuming vegan and vegetarian eating patterns, compared
with other dietary patterns.
Many Seventh-day Adventists limit or avoid meat and
other animal products, whereas others do not, providing
a unique opportunity to study the eects of dierent diet
patterns (10). In 1985, Snowdon and Phillips rst reported
a strongly positive association between meat consumption
and diabetes prevalence in 25,698 men and women from
California who were followed for 21 y in the Adventist
Mortality Study (11). Fifty per cent of this cohort reported
following a vegetarian diet. Age-adjusted diabetes prevalence
ratios in participants who consumed meat 6 or more times
per week were 1.9 for men and 1.6 for women, compared
with vegetarians (11). Fraser reported similar ndings from
the Adventist Health Study, in which men and women
meat consumers reported a 97% (OR: 1.97; 95% CI: 1.56,
2.46, P=0.0001) and 93% (OR: 1.93; 95% CI: 1.65, 2.25,
P=0.0001) greater diabetes risk, respectively, compared with
vegetarian participants (10). Vang et al. (12) followed 8401
Adventists, all of whom were free of diabetes at study onset,
for 17 y. After controlling for dierences in body weight,
those who consumed any type of meat (including poultry)
diabetes during the follow-up period, compared with those
who consumed no meat (12).
The Adventist Health Study-2 (AHS-2), which started
in 2002, included 22,434 men and 38,469 women living
throughout the USA and Canada; 65.5% were non-Hispanic
white and 26.9% were black (13). Compared with nonveg-
etarians, the OR for diabetes prevalence was 49% (0.51;
95% CI: 0.40, 0.66) less among vegans and 46% (0.54;
95% CI: 0.49, 0.60) less among lacto-ovo vegetarians, after
adjustments for BMI and other lifestyle variables (13).
Diabetes prevalence among those limiting meat consumption
to sh was 30% (0.70; 95% CI: 0.61, 0.80) less and those
eating meat less than once per week was 24% (0.76; 95% CI:
0.65, 0.90) less compared with the nonvegetarians. The vegan
participants consumed 33% more fruits and vegetables than
the nonvegetarians and avoided animal products that are
high in saturated fat and are associated with insulin resistance
In a prospective analysis of this same cohort (AHS-2) of
15,200 men and 26,187 women (17% black) who did not
have diabetes at baseline, vegan and lacto-ovo vegetarians
had a 77% and 54% reduction in risk of developing diabetes,
respectively (4). After controlling for BMI and other lifestyle
factors, odds were 62% less for vegans and 38% less for the
lacto-ovo vegetarians. The reduced risk was particularly pro-
nounced among black vegans who, in the adjusted analysis,
(52% reduced risk), compared with nonvegetarians (4). The
Adventist studies suggest a strong reduction in diabetes risk
as a result of avoiding animal-derived products that is, in part,
independent of the diet’s benecial eects on body weight.
Harvard study that included 26,357 men from the Health
Professionals Follow-Up Study (1986–2006), 48,709 women
from the Nurses’ Health Study (1986–2006), and 74,077
women from the Nurses’ Health Study II (1991–2007)
associated with a 48% (1.48; 95% CI: 1.37, 1.59) increase
in diabetes risk over a 4-y period (14). Decreasing meat
portions by half a serving a day was associated with a
reported 14% (0.86; 95% CI: 0.80, 0.93) reduction in diabetes
risk. In another report that included over 200,000 men and
16,162 participants developed diabetes during 4,102,369
person-years of follow-up (15). It was reported that when
participants followed a healthy plant-based diet that focused
on whole grains, fruits, and vegetables, and was low in rened
grains, sugar-sweetened beverages, and red and processed
meats, there was an associated 34% reduction in diabetes risk
Similarly, the European Prospective Investigation into
Cancer and Nutrition (EPIC) study’s InterAct Project
followed 340,234 adults from 8 European countries for
11.7 y and reported signicant associations between meat
consumption and type 2 diabetes risk (16). For men,
consumption of red and processed meat increased diabetes
risk, whereas for women there was a positive association
between total meat and poultry consumption (16).
In the Rotterdam study, a high intake of plant-derived
products and a low intake of animal products was associated
with lower insulin resistance, prediabetes, and type 2 diabetes
(17). These outcomes remained signicant after adjustment
for body weight (17). The authors proposed that dietary
guidelines should recommend a plant-based diet to reduce
the burden of type 2 diabetes.
In Taiwan, the Tzu Chi Health Study found signicant
reductions in diabetes risk among vegetarian Buddhists.
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Compared with the omnivore group (N =2900), the
vegetarian group (N =1484) had a 51% lower risk in
men (OR: 0.49; 95% CI: 0.28, 0.89) and a 75% lower risk
in postmenopausal women (OR: 0.25; 95% CI: 0.15, 0.42)
for type 2 diabetes after controlling for BMI and other
lifestyle factors (18). It should be noted that “omnivores”
in this population consume relatively little meat or sh by
Western standards. The vegetarian group consumed more
soy products, total and green leafy vegetables, nuts, and
whole grains, less tea, and a similar amount of dairy products
and fruits, compared with the omnivores (18). Within the
vegetarian group were a small number of vegans (N =69)
among whom no cases of diabetes were found.
A Plant-Based Eating Pattern Is Eective for
Treating Type 2 Diabetes
Plant-based diets, particularly vegan diets, improve glycemic
control, body weight, and cardiovascular risk factors in
individuals with type 2 diabetes. Each of these is central
to diabetes management and is described below. A meta-
analysis of 6 randomized controlled trials (N =255)
demonstrated that vegetarian diets were associated with a
0.4% greater reduction in glycated hemoglobin (HbA1c)
when compared with other prescribed eating patterns for
diabetes (19).
Low-fat, plant-based diets improve glycemic control.
Various formulations have been tested for many years.
In 1979, a 16-d, mainly plant-based, dietary intervention
designed to maintain body weight was tested in a closed
eliminate insulin, and the other 11 were able to reduce it by
60% after following a high-ber, high-carbohydrate diet (65 g
of ber, 70% calories from carbohydrate, 21% from protein,
9% from fat) (20).
A 22-wk randomized controlled trial compared a low-fat,
vegan diet (N =49) to a conventional portion-controlled diet
(N =50). The vegan diet (10% of energy from fat, 15%
protein, and 75% carbohydrate) excluded animal products
and favored low-fat, low-glycemic-index foods. The portion-
controlled diet (15–20% protein, <7% saturated fat, 60–70%
carbohydrate and monounsaturated fats) was individualized,
following 2003 American Diabetes Association guidelines
(21). Those with a BMI >25 kg/m2were prescribed energy
intake decits of 500–1000 kcal/d. Among participants
who made no medication changes, the vegan group had a
signicantly greater reduction in HbA1c (1.23% compared
with 0.38%, [P=0.01]) (22). The Pearsons correlation of
weight change with HbA1c change was r=0.51, P<0.0001
within the vegan group, suggesting that factors other than
weight changes inuence glycemic control. The authors
proposed that high-fat diets increase lipid accumulation in
the skeletal muscle, which contributes to insulin resistance
by reducing mitochondrial activity.
Vegan diets have been shown to improve glycemic control
in Asian populations that are already consuming diets that
are generally rich in plant-derived foods. In a Korean
study, 93 volunteers with type 2 diabetes were randomly
assigned to either a vegan diet (N =46) or a conventional
diet recommended by the Korean Diabetes Association
(KDA) 2011 (N =47) for 12 wk (23). The vegan diet
consisted of whole grains, vegetables, fruit, and legumes. The
mean HbA1c concentrations fell in both groups, however,
the reductions were greater for the vegan group (–0.5%
compared with –0.2%; P-interaction =0.17). These results
were greater in the participants who closely followed the
prescribed eating patterns (–0.9% compared with –0.3%)
Potential Mechanisms by Which Plant-Based
Eating Patterns Aect Insulin Resistance and
Weight Management
Insulin resistance
Insulin resistance and subsequent impairment in β-cell
function are the hallmarks of type 2 diabetes pathophysiology
(24). Plant-based eating patterns are benecial for patients
with diabetes by improving insulin sensitivity and improving
body weight. Insulin resistance is caused by lipid accumu-
lation within muscle and liver cells that typically begins
many years before the diagnosis of type 2 diabetes. This
lipid accumulation is highly responsive to diet changes. High-
fat diets downregulate the genes required for mitochondrial
oxidative phosphorylation in skeletal muscle (25). High-fat
diets also appear to disrupt the normal intestinal barrier
to bacterial endotoxins that, entering the bloodstream, may
disrupt glucose oxidation processes (26). The eects of
changes in fat intake on glycemic control can be observed,
not only after long-term interventions, but after single meals;
high-fat meals can cause postprandial elevations in plasma
glucose that can remain high for a long period of time
In a case-control study, Go et al. (28)compared24
healthy vegans to 25 healthy omnivores matched for sex, age,
BMI, per cent body fat, energy intake, and physical activity
levels. Individuals who followed a vegan diet had signi-
cantly lower intramyocellular lipid concentration, which was
associated with 32% greater homeostatic model assessment
of β-cell function (28). In a randomized trial in overweight
nondiabetic individuals without limitations on energy or
carbohydrate intake, a low-fat vegan diet reduced hepatocel-
lular lipid concentrations by 34.4% and intramyocellular lipid
concentrations by 10.4%. These changes in hepatocellular
and intramyocellular lipid concentrations correlated with
changes in insulin resistance (both r=0.51; P=0.01) (29).
These ndings suggest that low-fat, plant-based (especially
vegan) diets improve glycemic control because of their ability
to reduce lipid accumulation in muscle and liver, in addition
to their eects on body weight.
Plant-based diets may also improve β-cell function. In
a randomized trial, 75 participants who were overweight
or obese were assigned to a low-fat plant-based diet or no
diet changes for 16 wk. Meal-stimulated insulin secretion
markedly increased in the intervention group compared
Plant-based nutrition for diabetes 3
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with controls (interaction between group and time, G×t[P
<0.001]) (30). This study demonstrates the potential that a
plant-based eating pattern can play a role in reversing β-cell
dysfunction and peripheral insulin resistance in patients with
type 2 diabetes.
Weight management
Weight management plays an important role in improving
insulin sensitivity and glycemic control and reducing cardio-
vascular disease (CVD) risk factors (31). Excess body weight
is associated with risk of CVD and all-cause mortality among
people with type 2 diabetes (32). Individuals following
vegetarian, especially vegan, diets have lower mean BMIs,
compared with nonvegetarians (33). Population studies
have revealed that body weight increases progressively with
increased meat consumption (10,34).
In addition to preventing weight gain, a plant-based eating
pattern is an eective weight management tool (35,36).
In randomized trials, plant-based interventions for patients
compared with control diets containing animal products (22,
23,37), with a major portion of weight loss attributable to
a loss of visceral fat, a major advantage for reducing insulin
resistance and inammation (23,37). The BROAD study
demonstrated signicant weight loss using a low-fat (7–
15% of calories from fat), plant-based diet in overweight
individuals with 1 of the following comorbidities: type 2
diabetes, ischemic heart disease, hypertension, or hyperc-
holesterolemia (38). Sixty-ve adults (aged 35–70 y) were
randomly assigned to the plant-based diet or usual care. The
group compared with the usual-care group (4.4 compared
with 0.4, dierence: 3.9) (95% CI: ±1, P<0.0001). At 12 mo,
the reduction in BMI in the plant-based group was 4.2 (±0.8).
The program did not require restrictions on portion sizes, yet
participants reported feeling satised, potentially enhancing
compliance (38).
In a randomized trial of individuals with type 2 diabetes,
a low-fat vegan diet prescribed with no energy-intake limits
was associated with greater weight loss at 22 wk, compared
with a conventional diet that required energy-intake restric-
tions (–6.5 kg compared with –3.1 kg [P<0.001]) (22). At 74
wk, weight loss remained signicant within each diet group
but not signicantly dierent between groups (–4.4 kg in
the vegan group and –3.0 kg in the conventional diet group,
P=0.25) (39).
In a 24-wk trial, researchers tested the eects of plant-
based diets when used in combination with other inter-
ventions, comparing an isocaloric vegetarian diet (animal
products were limited to 1 serving of low-fat yogurt per
day) with a conventional diabetes diet that followed the
guidelines of the Diabetes and Nutrition Study Group of the
European Association for the Study of Diabetes (37). Aerobic
exercise was added to both study groups for the second 12
wk of the study. The macronutrient breakdown was 60% of
kcal from carbohydrate, 15% protein, and 25% fat for the
vegetarian intervention and 50% from carbohydrate, 20%
protein, and <30% fat (7% saturated fat, <200 mg/d of
cholesterol) for the conventional group. Both diets restricted
calories by 500 kcal/d, which was individualized based
on indirect calorimetry (37). Meals were provided to the
participants in both groups, supporting adherence to the
prescribed diet interventions. The vegetarian intervention
resulted in more weight loss (–6.2 kg; 95% CI: –6.6, –
5.3 compared with –3.2 kg; 95% CI: –3.7, –2.5; interaction
group ×time P=0.001) and greater improvements in insulin
sensitivity (30%; 95% CI: 24.5, 39 compared with 20%; 95%
CI: 14, 25). Reductions in visceral and subcutaneous fat were
signicantly greater (P=0.007 and P=0.02, respectively) in
the vegetarian group (37).
Weight loss on plant-based diets appears to be attributable
to 2 main diet eects. First, increased ber and carbohydrate
density of the diet. Second, plant-based diets have been
shown to increase postprandial metabolism (the thermic
eect of food) (36). In a randomized trial, participants with
a diagnosis of overweight or obesity (BMI 28–40) were
assigned to either a low-fat, vegan diet or to make no dietary
changes for 16 wk. The vegan group lost 5.9 kg (95% CI: 5.0,
6.7 kg; P<0.001) and its thermic eect of food (measured by
indirect calorimetry) increased by 14.1% (95% CI: 6.5, 20.4;
P<0.001). These changes were associated with reductions in
hepatocellular and intramyocellular fat and increased insulin
sensitivity (29).
Plant-Based Eating Pattern for Macrovascular
and Microvascular Complications of Diabetes
The eects of plant-based diets on glycemia, body weight,
plasma lipids, and blood pressure collectively reduce the risk
of CVD, the leading cause of morbidity and mortality in
diabetes patients. CVD encompasses coronary heart disease,
cerebrovascular disease, and peripheral arterial disease (32).
A meta-analysis of 9 randomized controlled trials in patients
with type 2 diabetes (N =664), comparing vegetarian
interventions with control diets, showed signicant improve-
ments in CVD risk factors, including lipids, blood pressure,
glycemic control, body weight, and abdominal adiposity
In addition to being associated with reduced CVD
risk, a plant-based diet may help reverse atherosclerotic
plaques. Ornish et al. demonstrated signicant regression in
coronary artery stenosis in patients with moderate to severe
coronary artery disease. Participants were randomly assigned
to usual care or a low-fat vegetarian diet combined with
exercise, stress management, and smoking cessation. After
5 y there was a mean reduction in atherosclerotic stenosis
in the vegetarian group, whereas there was a progression of
atherosclerosis in the control group. The control group was
also more likely to have required coronary angioplasty and
bypass surgery than the vegetarian group (41).
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Microvascular complications
Chronic kidney disease.
Chronic kidney disease is increasingly prevalent, and dia-
betes accounts for 44% of all new cases; 20–40% of patients
with diabetes have chronic kidney disease (42). A Western
dietary pattern, characterized by a high consumption of red
meat, fat, salt, and sugar, is a major contributor to metabolic
disturbances leading to the progression of kidney disease
(43). In the Nurses’ Health Study, women with mild renal
insuciency at baseline had a signicantly greater reduction
in renal function with greater consumption of animal protein
(especiallyfrommeat)overan11-yperiod(44). In contrast,
a 24-y follow-up of 14,868 adults in the Atherosclerosis Risk
and Communities Study found that a higher adherence to a
healthy plant-based diet was associated with a lower risk of
chronic kidney disease (45).
Several studies have reported a reduction of urinary
albumin excretion in patients with diabetic nephropathy
when consuming a plant-based or reduced-red-meat diet
(46–48). One study showed a 54% decrease in urinary
albumin in patients with type 1 diabetes after 8 wk of a plant-
based diet (48).ThestudybyBarnardetal.describedabovein
which patients with type 2 diabetes followed a low-fat vegan
diet, reported a signicant reduction in urinary albumin in
participants following a low-fat vegan diet, with no change
in the control group following a portion-controlled diet
More than 50% of individuals with diabetes suer from
neuropathy (49). Common clinical manifestations include
pain, insensitivity to injury, orthostatic hypotension, cardiac
autonomic neuropathy, gastroparesis, and erectile dysfunc-
tion (50). Diabetic neuropathycan lead to sleep disturbances,
depression, and anxiety (51), and eventually amputations
(52). Current treatment of diabetic neuropathy includes
glycemic control to slow disease progression and medi-
cations for neuropathic pain (42). There is no pharma-
cological treatment that reverses nerve damage caused by
neuropathy, apart from methods for improving glycemic
A 20-wk randomized, controlled trial using a low-fat,
vegan intervention demonstrated improved nerve function,
as measured by electrochemical skin conductance in the foot,
and reduced pain, compared with an untreated control group.
(53). These results are consistent with 2 smaller studies that
used a vegan diet, one combined with exercise in which
painful neuropathy symptoms were eliminated in 17 out of 21
patients (54) and another in which cutaneous reinnervation
and reduced pain were reported in 30 individuals with
impaired glucose tolerance (55).
Diabetic retinopathy.
has not been studied. However, a plant-based diet is eective
in controlling risk factors for diabetic retinopathy, including
glycemia (19), blood pressure (56), and lipids (57). Studies
have also demonstrated that diets high in fruits, vegetables,
retinopathy (58).
Comparing a Plant-Based Diet with Key Aspects
of Other Dietary Approaches for Type 2
Very-low-calorie diets and metabolic surgery
Reversalofinsulinresistanceandβ-cell dysfunction with as-
sociated reductions in pancreatic and hepatic triacylglycerol
stores has been demonstrated in patients with type 2 diabetes
with very-low-calorie diets (600 kcal/d) or bariatric surgery
(59). These interventions are not free from clinical challenges
or risk. Very-low-calorie diets require medical management
by trained practitioners and may only be appropriate in select
patients. Further, the long-term sustainability of such diets is
limited; they are frequently followed by progressive weight
gain (60,61). Adverse eects of metabolic surgery include
mortality (rates 0.1–0.5%), dumping syndrome, nutritional
deciencies, increased risk of depression, and substance
abuse (62). A plant-based diet may provide improvements for
diabetes without intentional caloric reduction and may do so
independently of weight loss.
Mediterranean and Dietary Approaches for Stopping
Mediterranean and Dietary Approaches for Stopping Hyper-
tension (DASH) diets both emphasize the intake of plant-
based foods with controlled portions of animal products.
Mediterranean diets have been tested for the prevention and
treatment of diabetes. Like a plant-based diet, Mediterranean
diets emphasize the consumption of fruits, vegetables, whole
grains, and legumes, and reduce meat, rened grains, and
sugar, while allowing modest amounts of animal products.
The term “Mediterranean diet” may be interpreted dierently
by dierent people. In research studies, the term refers to a
diet that includes abundant plant-based foods, favors olive
oil as the primary source of fat, and includes low to moderate
amounts of meat, dairy products, eggs, and wine (63). A
high score (range 0 to 9) for Mediterranean diet-style intake,
measured by study participants’ consumption of fruits,
of MUFAs to SFAs, was associated with a 30% reduced risk of
developing diabetes in over 25,000 women followed for 20
y. The high Mediterranean diet scores were associated with
lower biomarkers of insulin resistance (adiposity, lipoprotein
metabolism, and inammation) (64). A meta-analysis of 9
randomized controlled trials with 1178 patients with type 2
diabetes compared a Mediterranean diet with control diets
resulting in a greater reduction in HbA1c (mean dierence,
–0.30; 95% CI: –0.46, –0.14). There were also improvements
in body weight and cardiovascular risk factors (65).
The outcomes for weight loss using a Mediterranean
diet have been mixed. Although a 2016 systematic review
reported that clinical trials using Mediterranean diets showed
Plant-based nutrition for diabetes 5
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TABLE 1 Dietary sources of key nutrients on a plant-based diet
Nutrient Dietary sources Importance for plant-based nutrition and diabetes
Protein Legumes, whole grains, vegetables, nuts, and seeds Consuming more animal protein may increase the risk of type 2
diabetes compared with consuming less and compared with
replacing the animal sources with vegetable protein sources (66)
ω-3 fatty acids Seeds (hemp, chia, flax), walnuts, leafy green vegetables,
microalgae, soybeans, wheat germ
A low-fat, plant-based diet will be lower in ω-6 fatty acids, thus
allowing for a more ideal ratio to ω-3 fatty acids, with a lower ratio
being preferable (68)
Iron Legumes; leafy greens such as spinach, Swiss chard, kale,
collards, and beet greens; raisins; blackstrap molasses;
pumpkin seeds
Iron deficiencies do not manifest in those following a plant-based
diet any more than in those following other diet patterns (9).
Insulin resistance may be increased by heme iron found only in
animal products (69)
Zinc Legumes, soybeans, nuts, seeds, whole grains Zinc deficiencies do not manifest in those following a plant-based
diet any more than in those following other dietary patterns (9)
Iodine Sea vegetables, iodized salt, supplements Iodine is important for thyroid health
Calcium Kale, collard greens, bok choy, broccoli, green cabbage,
Brussels sprouts, fortified plant milks and juices,
calcium-set tofu, almonds, sesame seeds
The absorption rate of calcium from greens is sometimes twice as
high as calcium from cow milk, which has an absorption rate of
30% (70)
Vitamin D Sunshine exposure and supplements Vitamin D status may improve inflammation and oxidative stress
among diabetes patients (71)
Vitamin B-12 Fortified foods and supplements Anyone over the age of 50 and taking certain medications, including
metformin, could benefit from taking a vitamin B-12 supplement,
regardless of eating pattern (72)
signicant weight loss, all of the included studies used
exercise or calorie restriction, confounding the eects of the
dietary change (73). The well-controlled Lyon Diet Heart
Study (74) and the Prevención con Dieta Mediterránea
(PREDIMED) study (75) led to no clinically signicant
weight loss. In a crossover trial including 62 overweight
adults, a low-fat vegan diet led to signicantly greater weight
loss over a 16-wk intervention period, compared with a
Mediterranean diet (76).
The DASH diet was developed to lower blood pressure
without medications. The eating pattern emphasizes fruit,
vegetables, fat-free/low-fat dairy, whole grains, nuts, and
legumes, and limits saturated fat, cholesterol, red and
processed meats, sweets, added sugars, salt, and sugar-
sweetened beverages. In an umbrella review of systematic
reviews and meta-analyses on cardiometabolic outcomes, the
DASH diet was associated with a signicant reduced risk of
diabetes (RR: 0.82; 95% CI: 0.74, 0.92) as well as signicant
reductions in CVD, coronary heart disease, and stroke, and
reductions in blood pressure and body weight. There were no
signicant changes in HDL cholesterol, triglycerides, fasting
blood glucose, HOMA-IR, or C-reactive protein. This review
included 2 controlled trials evaluating the DASH diet in
individuals with diabetes which resulted in a reduction in
HbA1c (–0.53%; 95% CI: –0.62, –0.43) and fasting insulin (–
0.15 μU/mL; 95% CI: –0.22, –0.08) (77).
The absence of any need for portion control is an advan-
tage of a low-fat vegan diet over Mediterranean and DASH
eating patterns. The DASH diet does not appear to provide
the reduction in inammation and improvement in insulin
sensitivity that has been documented in the vegan diet. Given
that even small amounts of animal products may increase
the risk of diabetes (in the AHS-2, the vegan diet provided
a major advantage in reducing the risk of diabetes compared
with the lacto-ovo vegetarian or the semivegetarian where
meat consumption was limited to 1 time a month and <1
time/wk), there are theoretical advantages to avoiding animal
products altogether.
Low-carbohydrate eating pattern
Low-carbohydrate diets cause weight loss in overweight
individuals, although they are no more eective for weight
loss than plant-based diets or other dietary approaches in
1-y comparisons (78,79). The common idea that low-
carbohydrate diets suppress appetite was challenged in a
2021 metabolic-ward study (80). Twenty young overweight
adults were assigned to a low-fat, vegan diet (10% fat, 75%
carbohydrate) or a low-carbohydrate diet (76% fat, 10%
carbohydrate) for 2 wk, then switched to the opposite diet
for an additional 2 wk (80). The vegan diet led to a much
greater drop in calorie intake; energy intake was 689 (±73)
kcal/d lower during the vegan phase, compared with the low-
carbohydrate phase (P<0.0001) (80).
In individuals with diabetes, low-carbohydrate diets may
cause an initial reduction in blood glucose values, but these
benets are often largely gone by 12 mo (81).
There may be some safety concerns with a low-
carbohydrate diet. They often elevate plasma LDL cholesterol
concentrations, with widely varying eects between
individuals (82). Because low-carbohydrate diets restrict or
eliminate fruits, whole grains, legumes, and other healthful
foods, and are often high in saturated fats, they raise concerns
about long-term risk of cancer, Alzheimer’s disease, and
other conditions. Long-term use of low-carbohydrate
diets is associated with increased all-cause mortality
6 Jardine et al.
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TABLE 2 Guidelines for implementing plant-based nutrition in clinical practice
Consider patient referral
Health care providers are encouraged to refer patients to a registered dietitian nutritionist (RDN) who specializes in plant-based nutrition. RDNs are
trained to do a thorough nutrition assessment as well as education and counseling. Medicare and most insurance plans cover medical nutrition
therapy (MNT)
Patient assessment for plant-based nutrition
rReadiness for change
rAssess current eating pattern
rFamily and social support
rCultural/religious beliefs
rEducation and socioeconomic traits
rLifestyle: sleep, exercise, tobacco, alcohol, and substance use
rEmotional well-being
rUse of glucose monitoring (self-monitoring of blood glucose/continuous glucose monitoring)
rCulinary skills
rFrequency of eating out and/or traveling
rCurrent dietary habits:
rPlant-based eating habits: fiber, servings of fruit, vegetables, whole grains, legumes, nuts, and seeds
rIntake of animal products and refined carbohydrates: chicken, fish, red meat, processed meat, eggs, dairy (including cheese), fried food,
refined sugar, sugar-sweetened beverages, and processed and fast food
Note: this is in addition to a comprehensive medical evaluation described in the ADA Standards of Care that includes medical and family history,
medications, vaccinations, and technology use (137).
Education: principles of plant-based nutrition
rFocus on the 4 food groups (see Tabl e 3)
r2–4 servings of fruit
r3–5 servings of vegetables
r5–8 servings of whole grains
r2 or more servings of legumes
rLimit added oils, fried foods, and other high-fat foods
rLimit nuts and seeds to 1 ounce per day (scant 1
4cup or 2 tablespoons of nut butters)
rAim to consume 40 g of fiber per day. A gradual intake may be necessary to minimize gastrointestinal symptoms
rAvoid all animal products including meats, fish, dairy, and eggs
rSupplement with vitamin B-12: 500–1000 μ2–3 times per week (5)
Methods of intervention
rMeal planning
rGrocery shopping and label reading
rCooking techniques
rSelf-monitoring of blood glucose
rConcerns and treatment of changes in blood glucose with diet intervention (treatment of hypoglycemia)
rHave patient education materials:
rList of appropriate websites
rConsider using telehealth to provide care and education and send motivational messages to patients on a regular basis
rProvide group classes:
rOngoing support groups
rCooking classes
Topics to cover:
Follow-up and ongoing support
rMonitor body weight, self-monitoring of blood glucose, HbA1c, lipids, and blood pressure
rAssess for potential of medication-induced hypoglycemia or hypotension, and adjust medical therapy as needed
rReview diet records
rUse failures as opportunities for problem-solving and skill development
ADA, American Diabetes Association; HbA1c, glycated hemoglobin.
In terms of safety, plant-based diets reduce diabetes risk
without untoward side eects. The same is true for treatment
of diabetes with some precautions for hypoglycemia. In
the study by Barnard et al., 43% of the subjects in the
low-fat vegan group had to reduce or eliminate their diabetes
medications in response to hypoglycemia (22). Low blood
glucose concentrations can be avoided by frequent glucose
monitoring, patient education, and adjusting medications
as needed. Plant-based eating patterns have been found
to have a high diet quality and are nutritionally adequate.
Plant-based nutrition for diabetes 7
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TABLE 3 Plant-based nutrition food groups
Food group Foods Serving size Servings per day
Vegetables: include a
variety of colors from the
rainbow: red, yellow,
orange, green, and
Artichokes, asparagus, beets, bok choy, broccoli,
Brussels sprouts, cabbage (all colors), carrots,
cauliflower, celery, collards, cucumbers, eggplant,
endive, garlic, ginger, green beans, k ale, lettuce,
mustard and turnip greens, okra, onions, parsnips,
peppers, potatoes (all varieties), pumpkin, radishes,
spinach, squash (all varieties), tomatoes, turnip,
1 cup raw
2cup cooked
3 to 5 or more servings
or unlimited
Fruits Apples, apricots, bananas, berries, citrus fruit, cherries,
dates, grapes, kiwi fruit, kumquats, mangos,
papayas, peaches, pears, pineapples, plums,
pomegranates, melons, raisins
1 cup chopped
2 tablespoons dried
2 to 4 or more servings
Whole grains: choose whole
grain versus refined as
much as possible
Amaranth, barley, bread, buckwheat, bulgur, cereal
(hot or cold), corn, millet, oats (rolled, steel cut, or
groats), pasta, popcorn (air-popped), quinoa and
2cup any cooked grain
4cup dry cereal
1 slice bread
1 tortilla
5 to 8 or more servings
Legumes Anasazi beans, adzuki beans, baked beans, black
beans, chickpeas, dahl, hummus, lima beans,
lentils, navy beans, peas, pinto beans, soy milk,
tempeh, and tofu
4cup hummus
4cup dry legumes
2cup cooked beans, lentils,
peas, tofu, tempeh
Nuts and seeds Almonds, Brazil nuts, cashews, hazelnuts, macadamia,
peanuts, pinons (pine nuts), pistachios, walnuts,
and seeds: pumpkin, sunflower, hemp, flax, and
Limit to:
2 tablespoons nut butter
Herbs and spices Fresh or dried herbs and spices without salt added unlimited
Water and tea Water or herbal teas without sugar added 8 ounces 8 servings
According to the Academy of Nutrition and Dietetics (AND),
“appropriately planned vegetarian, including vegan, diets are
healthful, nutritionally adequate (9).”
Considerations for the Use of a Plant-Based Diet
for Diabetes
Caregivers should help patients who have (or are at risk
of) diabetes to understand the benets of a plant-based
eating pattern and encourage a trial. Patients are typically
willing to try a plant-based diet when its rationale has
been explained, and they can adapt nutrition guidelines
to suit their preferences (84). The fact that a plant-based
diet does not require limits on calories, carbohydrates, or
portions makes it appealing, and most patients nd it to
be no more challenging than other therapeutic diets (85).
Further, the acceptability of a low-fat plant-based diet has
been shown to be comparable to other therapeutic eating
patterns in randomized trials with individuals with diabetes
(85). Adopting a plant-based diet is often highly motivating
due to the improvements with weight loss, glycemic control,
and enhanced quality of life (86).
According to AND, vegan and vegetarian diets are
nutritionally adequate and may provide health benets for
the prevention and treatment of certain diseases, including
type 2 diabetes (9). Plants provide all required vitamins
and minerals except vitamin B-12. Vitamin B-12 is made
neither by plants nor animals but rather by microbes.
Although cereals, plant-based milk, and other plant-based
foods may be fortied with vitamin B-12, a B-12 supplement
will ensure adequacy. AND recommends adults following
a plant-based diet take 500 to 1000 μg several times per
week (9). Metformin use increases the risk of vitamin B-12
deciency, which can contribute to symptoms of neuropathy.
Periodic testing of vitamin B-12 status is suggested by the
American Diabetes Association (ADA) (87). Tab l e 1 is a
resource for dietary sources of key nutrients on a plant-based
Once patients have a good list of meal possibilities, the
next step is to adopt a fully vegan diet for 3 wk. This
“test drive” is short enough to be readily approachable,
particularly since patients have already drawn up a list of
suitable foods, but it is long enough for health benets to be
noticed. For maximum impact, it is best to ask patients to (1)
avoid all animal products, (2) minimize the use of oils and
oily foods, and (3)favorfoodsthatarehighinber.
Involving the family will shore up support for the
diet changes at home and diminish potential resistance.
Teaching in groups is often particularly eective; groups
bring added experiences, helpful questions, social support,
and, as time goes on, validation for the eectiveness of
the diet change. Additional guidance on how to deal with
social situations and traveling will ensure success. Handouts,
books, videos, and recipes should be readily available in
waiting rooms and examination rooms or made accessible
online. Ta b l e 2 provides guidelines for implementing plant-
based nutrition in clinical practice. Tab l e 3 has a list
8 Jardine et al.
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of plant-based nutrition food groups and recommended
Adjusting medications in response to a plant-based diet
It is essential to help patients anticipate blood glucose
changes in response to the new eating pattern. Hypoglycemia
is common among individuals treated with insulin or
sulfonylureas as they improve their diets, often necessitating
medication reduction or discontinuation. There is a need for
the development of evidence-based deprescribing guidelines
for patients with type 2 diabetes who need to reduce
medication in response to episodes of hypoglycemia in the
context of a plant-based diet.
Observational studies and randomized controlled trials
support the benets of plant-based nutrition for diabetes. The
consumption of whole grains, legumes, fruits, and vegetables
in conjunction with the elimination of animal products
reduces the risk of developing type 2 diabetes. In individuals
with type 2 diabetes, a low-fat, plant-based diet improves
body weight, glycemic control, plasma lipid concentrations,
and blood pressure, while reducing the risk of CVD and
microvascular complications.
Health care providers should feel condent in counseling
their patients to follow a plant-based eating pattern and
should be prepared to provide education and support to
improve their patients’ diabetes outcomes, general health,
and psychological well-being.
Further research on the eects of a plant-based diet for
on their role in improving management of type 1 diabetes,
would be helpful. High-quality studies comparing vegan
and vegetarian eating patterns with DASH and or the
Mediterranean eating patterns would provide more detail
on how various eating patterns aect diabetes outcomes.
Guidelines on reducing reliance on antihyperglycemic med-
ications in response to plant-based lifestyle therapy would
assist health care providers in reducing the risk of hypo-
glycemia and other untoward side eects associated with
The authors’ contributions were as follows: MAJ, developed
for writing the nal manuscript; HK, provided content on
plant-based diet; SML, worked on the nutrition content as
well as providing editing for each draft; ZA, researched and
wrote content on the mechanisms section of the article; CBT,
wrote section adjusting medications as well as editing to the
nal manuscript; NDB, added content on complications of
diabetes, the mechanisms section as well as providing edits
to the nal manuscript; and all authors: read and approved
the nal manuscript.
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Plant-based nutrition for diabetes 11
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... The associated factors in diabetes mellitus are often complicated and interrelated and include; age, sex, body weight genetics, viral factors, immune deficiency, trauma and the environment [10,11]. The environmental factors however depend on the geographical location of an individual [12]. The etiology of Type 2 DM is meanwhile associated with lifestyle and dietary practices of an individual with an exposure [13]. ...
... Subjects in the study had15fold risk of developing Type 2 diabetes mellitus. This finding of our study is also consistent with that of [12] who found a six-fold risk of developing diabetes mellitus among siblings in a Saudi Arabia study. ...
... vegetables (5,6) may be among the reasons for the global increase in type 2 diabetes (T2D) incidence (1,7). ...
... A 2021 review emphasized the importance of plant-based foods and the increment of vegetables in the diet in reducing the risk of T2D (7). This is supported by findings from a large European study based on selected biomarkers of fruits and vegetables (a-carotene, b-carotene, lutein), which suggest a higher intake of vegetables may be inversely associated with T2D (8). ...
Objective: To examine the relationship between intake of vegetables/potatoes and incident type 2 diabetes (T2D) and explore whether the relationship between vegetable intake and incident T2D is mediated by baseline BMI. Research design and methods: Cross-sectional associations between exposure (baseline intake of total vegetables, vegetable subgroups, and potatoes) and baseline BMI were assessed by multivariable-adjusted linear regression models. Associations between exposure and incident T2D were examined by multivariable-adjusted Cox proportional hazards models. Mediation by BMI was quantified through exploration of natural direct and indirect effects. Results: Among 54,793 participants in the Danish Diet, Cancer and Health cohort, 7,695 cases of T2D were recorded during a median follow-up of 16.3 years. Participants in the highest total vegetable intake quintile (median 319 g/day) had a 0.35 kg/m2 (95% CI -0.46, -0.24) lower BMI and a 21% (95% CI 16, 26%) lower risk of incident T2D after multivariable adjustment compared with those in the lowest quintile (median 67 g/day). Baseline BMI mediated ∼21% of the association between vegetable intake and incident T2D. Participants in the highest compared with the lowest (median 256 vs. 52 g/day) potato intake quintile had a 9% (95% CI 2, 16%) higher risk of T2D after multivariable adjustment, with no association found after accounting for underlying dietary pattern. Of the vegetable subclasses, higher intake of green leafy and cruciferous vegetables was associated with a statistically significantly lower risk of T2D. Conclusions: The findings provide evidence that a higher vegetable, but not potato, intake might help mitigate T2D risk, partly by reducing BMI.
... Eating order is a specific detail of one's eating habit and often varies from person to person. Previous studies on eating orders have focused on glycemic control in adults with diabetes (22,23). Few studies have examined the link between eating order and risk of obesity. ...
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Background Early childhood is a critical period for dietary education and development of good eating habits. However, few studies have investigated the effect of eating order in children and childhood obesity in real-world settings.Objective To examine whether the order in which meats/fish or vegetables are consumed affects the risk of obesity in preschoolers.Methods We conducted a population-based cross-sectional study using a self-administered online survey on the lifestyle and health behaviors of preschoolers in Taizhou, China. A total of 3,200 parents were invited to take part in the survey, and 2,049 of them completed the questionnaire. Children were classified as having a normal weight, overweight, or obesity using the definitions provided by the International Obesity Task Force, and z-scores for body mass index were calculated. We divided the children's eating order at the beginning of the meal into two groups: “vegetables before meats/fish” or “meats/fish before vegetables”. We analyzed the relationship between what was consumed first at a meal and the overweight status of each child.ResultsNo difference in body mass index was observed between the children eating meats/fish-first and the children eating vegetables-first during a meal. Children with parents who were affected by obesity were more likely to eat vegetables first. Among children of mothers with obesity, body mass index was significantly higher in the meats/fish-first group than that in the vegetable-first group (2.891 vs. 0.845, P = 0.007). In children whose mothers were affected by obesity, those that ate meats/fish first had a 12.21 times higher risk of being overweight compared with those that ate vegetables first (95% CI:1.22–121.74, P = 0.033).Conclusion Our findings suggest eating vegetables or meats/fish at the start of a meal does not affect weight status in preschoolers.
... Although further research is always needed, a comparison of different dietary patterns has shown that a well-designed dietary pattern should primarily be based on unprocessed or minimally processed plant-based food [44,67]. The mechanisms of action are known and described in great detail elsewhere [60,[68][69][70][71][72][73][74][75]. Regardless, it is necessary to be aware that a sustainable diet can only be built on a multidisciplinary approach, as due to various objec-tive challenges/limitations in society (e.g., sociological, physiological, ethnic-traditional, geographical and economic), an easy shift to a stricter plant-based dietary pattern, therefore, cannot be a "one-way street" [76]. ...
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Background: Monitoring nutritional status data in the adult population is extremely important to mediate their health status. Unfortunately, for Slovenia (2.1 million European Union citizens), data on the body composition status of the general adult population are currently rare or nonexistent in scientific journals. Furthermore, dietary intake was last assessed several years before the COVID-19 epidemic period. Methods: We randomly recruited 844 adult Slovenes from all regions of Slovenia. The primary aim of the cross-sectional study was to examine body composition status (using a medically approved electrical bioimpedance monitor) during the post-COVID-19 epidemic period. In addition, we assessed dietary intake (using a standardized food frequency questionnaire) and compared the obesity propensity for both sexes separately using the body mass index (BMI) and body fat percentage (FAT%) obesity classification of the World Health Organization. Results: Regarding BMI classification, 43% of the whole sample was overweight (28%) or obese (15%), and there were more older adults than adults (64% vs. 42%, p < 0.001). The average FAT% of adult females and males was 26.9% and 19.5% (p < 0.001), respectively, while for older adult females and males, it was 32.7% and 23% (p < 0.001). In addition, a comparison of the proportions of obese people between the two cut-off obesity classifications (BMI vs. FAT%) showed a significantly underestimated proportion of obese female participants based on BMI classification (13% vs. 17%, p = 0.005). In terms of the dietary intake of the assessed nutrients in comparison with the national dietary reference values for energy and nutrient intake, the participants, on average, had lower intake than the recommended values for carbohydrates, fiber, vitamins C, D and E (for males) and calcium, and higher intake than the recommended values for total fat, saturated fatty acids, cholesterol, sodium and chloride (for males). Conclusions: The results urgently call for the need to not only improve the overall national nutritional status but also for regular national monitoring of body composition and dietary intake statuses.
... Plant-based diets (PBD) are becoming increasingly popular for their many health benefits, both in the prevention and treatment of disease. PBD have been shown to convey protective effects against obesity, diabetes, and other metabolic disorders [1][2][3]. In addition, there is mounting evidence that a plant-based diet is beneficial for heart health [4][5][6][7][8][9]. ...
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A plant-based diet (PBD) can provide numerous health benefits for patients with cardiovascular risk factors. However, an inadequately planned PBD also bear the potential for deficiencies in certain macro- and micronutrients. The present study analyzed nutrient profiles of individuals who adopted a PBD as part of the CardioVeg study. Participants with cardiovascular risk factors were randomly assigned to either a whole-food PBD intervention (n = 36; eight 90 min group meetings including two 120 min cooking sessions) or a control group asked to maintain an omnivorous diet (n = 34) for eight weeks. Food intake data were collected using three-day weighed food records and analyzed with NutriGuide software, including the German Nutrient Data Base (German: Bundeslebensmittelschlüssel). Nutrient intake was compared before and after eight weeks as well as between the groups. The results for both groups were then contrasted to the current dietary recommendations published by the societies for nutrition in Germany, Austria, and Switzerland. Moreover, anthropometric/laboratory data and ambulatory blood pressure monitoring were determined at baseline and after 8 weeks. Data of a subsample (n = 18 in the PBD group and n = 19 in the control group) were used for the present analyses of the dietary intake data. A PBD yielded several benefits including (but not limited to) a lower energy density, a lower intake of cholesterol and saturated fat, an increased consumption of fiber, and a lower intake of salt. Recommended intakes of most vitamins and minerals were generally met, except for vitamin B12 in the PBD group. A low intake of several other critical nutrients (vitamin D, iodine) was observed in both groups. Compared with the control group, PBD resulted in a significant decrease in body weight, body mass index, waist circumference, HbA1c, and fasting blood glucose after 8 weeks. Overall, it can be concluded that a PBD had a more favorable nutrient composition for cardiovascular health than the omnivorous dietary pattern of the control group.
... Other comorbidities of severe COVID-19 include diabetes (Landstra & de Koning, 2021) and obesity (Sjögren et al., 2021), and plant-based diets are associated with reduced risk of diabetes (Z. Chen et al., 2021;Jardine et al., 2021;McMacken & Shah, 2017) and obesity (Najjar & Feresin, 2019;Tran, Dale, Jensen, & Lied, 2020). High dietary sodium is also associated with diabetes (Hao et al., 2020;Lin et al., 2021) and obesity (Fang, He, Fang, & Lian, 2021;Grimes et al., 2021). ...
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Compared to an omnivorous Western diet, plant-based diets containing mostly fruits, vegetables, grains, legumes, nuts, and seeds, with restricted amounts of foods of animal origin, are associated with reduced risk and severity of COVID-19. Additionally, inflammatory immune responses and severe acute respiratory symptoms of COVID-19, including pulmonary edema, shortness of breath, fever, and nasopharyngeal infections, are associated with sodium toxicity from excessive dietary sodium. High dietary sodium is also associated with increased risks of diseases and conditions that are comorbid with COVID-19, including chronic kidney disease, hypertension, stroke, diabetes, and obesity. This article presents evidence that low dietary sodium potentially mediates the association of plant-based diets with COVID-19 prevention. Processed meats and poultry injected with sodium chloride contribute considerable amounts of dietary sodium in the Western diet, and the avoidance or reduction of these and other processed foods in whole food plant-based diets could help lower overall dietary sodium intake. Moreover, high amounts of potassium in plant-based diets increase urinary sodium excretion, and preagricultural diets high in plant-based foods were estimated to contain much lower ratios of dietary sodium to potassium compared to modern diets. Further research should investigate low sodium in whole food plant-based diets for protection against COVID-19 and comorbid conditions.
Background: A healthful plant-based eating pattern is associated with lower type 2 diabetes risk; however, the association with its preceding state, compromised insulin sensitivity, is less well-established, particularly in younger populations with repeated measures of diet over time. Objective: We aimed to examine the longitudinal relationship between a healthful plant-based eating pattern and insulin sensitivity in young to middle-aged adults. Methods: We included 667 participants from the Childhood Determinants of Adult Health (CDAH) study, a population-based cohort in Australia. Healthful plant-based diet index (hPDI) scores were derived from food frequency questionnaire data. Plant foods considered 'healthful' were scored positively (e.g., whole grains, fruit, vegetables), with all remaining foods scored reversely (e.g., refined grains, soft drinks, meat). Updated homeostatic model assessment (HOMA2) estimated insulin sensitivity from fasting insulin and glucose concentrations. We used linear mixed-effects regression to analyse data from two time points: CDAH-1 (2004-06, aged 26-36 years) and CDAH-3 (2017-19, aged 36-49 years). hPDI scores were modelled as between- and within-person effects (i.e., a participant's overall mean and their deviation from said mean at each time point, respectively). Results: The median follow-up duration was 13 years. In our primary analysis, each 10-unit difference in hPDI score was associated with higher log-HOMA2 insulin sensitivity [95% confidence interval], with between-person (β = 0.11 [0.05, 0.17], P < .001) and within-person effects (β = 0.10 [0.04, 0.16], P = .001). The within-person effect persisted despite accounting for compliance with dietary guidelines. Adjustment for waist circumference attenuated the between-person effect by 70% (P = .26) and the within-person effect by 40% (P = .04). Conclusions: In young to middle-aged Australian adults, a healthful plant-based eating pattern (determined using hPDI scores) was longitudinally associated with higher insulin sensitivity, and therefore, potentially lower type 2 diabetes risk later in life.
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Climate change is inducing us to rethink our way of life. There is widespread awareness that we need to adopt environmentally friendly approaches and reduce the amount of waste we generate. In medicine, nephrology was one of the first specialties to adopt a green approach. Plant-based or vegan-vegetarian diets, which are planet-friendly and associated with a reduced carbon footprint, were rapidly acknowledged as a valid method for reducing protein intake in the conservative management of chronic kidney disease (CKD). However, how the transition from an omnivorous to a plant-based diet should be managed is not universally agreed; there is little data in the literature and indications based on randomized trials fail to consider feasibility and patients' preferences. Nonetheless, in some conditions the use of plant-based diets has proved safe and effective. For example, in CKD pregnancies, it has reduced unfavorable maternal and fetal outcomes. This review will present the available evidence on the benefits of plant-based diets in CKD, as well as old and new criticisms of their use, including emerging issues, such as contaminants, additives and pesticides, from a green nephrology perspective.
Obesity and its association with metabolic syndrome are implicated in many disease states. Research has focused on the role of diet and lifestyle modifications in the evolution of prediabetes to diabetes seeking ways to intervene and improve outcomes. Proven nutritional include leaner proteins, an abundance of vegetables, extra-virgin olive oil, and controlled portioning of carbs and starches. The transition from a sedentary state to an exercise routine of moderate intensity has shown efficacy in lowering metabolic risks. The synergy of dietary and physical activity modifications are the building blocks for lifestyle modifications examined in this review as a means of preventing obesity-related diabetes.
Pulmonary fibrosis (PF) is characterized by oxidative injury and excessive collagen synthesis in lung fibroblasts, causing impaired pulmonary function and chronic lung injury. Piceatannol, a dietary polyphenol, possesses vital pharmacological effects in metabolic disorders, cancers, cardiovascular disease and infectious disease; however, its role in PF is still not completely elucidated. Mice (8 to 10 weeks old) were administered bleomycin (BLM) intratracheally (2 U/kg) to establish an in vivo PF model. Murine primary lung fibroblasts were isolated and stimulated with TGF-β (10 ng/mL) for 48 h to induce its activation. Meanwhile, mice or primary lung fibroblasts were treated with different doses of piceatannol to observe its protective roles. Pulmonary function and arterial blood gas were detected to assess pulmonary physiological status. Collagen deposition and the mRNA levels of profibrotic genes were determined by H&E staining and RT-PCR. Meanwhile, the protein and mRNA markers, as well as end-product of oxidative stress were detected in vivo and in vitro. The results showed that pulmonary function was significantly impaired in BLM-induced mice, accompanied by elevated oxidative stress and excessive collagen synthesis. Piceatannol significantly improved pulmonary function and decreased oxidative injury as well as collagen synthesis in mice with PF. Mechanically, piceatannol treatment significantly inhibited the activation of JAK2/STAT3 signaling pathway in BLM-induced mice and TGF-β-induced lung fibroblasts. Additional findings also demonstrated that coumermycin A1 (C-A1), an agonist of JAK2, could abolish the effects of piceatannol on TGF-β-induced lung fibroblasts and reactivated the phosphorylation STAT3. Taken together, our study demonstrated that piceatannol could protect against oxidative injury and collagen synthesis during PF in a JAK2/STAT3 signaling pathway-dependent manner.
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Objective: Evidence suggests that both Mediterranean and vegan diets improve body weight and cardiometabolic risk factors, but their relative efficacy has not been compared in a randomized trial. Methods: In a randomized crossover trial, 62 overweight adults were randomly assigned to a Mediterranean or vegan diet for a 16-week period. Body weight, plasma lipids, blood pressure, and body composition (dual X-ray absorptiometry) were measured. Secondary measures included insulin resistance (Homeostasis Model Assessment, HOMA-IR), oral glucose insulin sensitivity (OGIS), and predicted insulin sensitivity (PREDIM) indices. Thereafter, participants were asked to return to their baseline diets for 4 weeks, after which they began the opposite diet for 16 weeks. The same parameters were measured before and after this 2nd 16-week period. Results: Overall net weight changes were 0.0 (Mediterranean) and −6.0 kg (vegan), (treatment effect −6.0 kg [95% CI −7.5 to −4.5]; p < 0.001). HOMA-IR decreased and OGIS increased on the vegan diet with no significant change on the Mediterranean diet (treatment effect −0.7 [95% CI, −1.8 to +0.4]; p = 0.21; and +35.8 mL/min/m² [95% CI, +13.2 to +58.3]; p = 0.003, respectively). PREDIM did not change significantly in either group. Among participants with no medication changes, total and LDL-cholesterol decreased 18.7 mg/dL (0.5 mmol/L) and 15.3 mg/dL (0.4 mmol/L), respectively, on the vegan diet, compared with no significant change on the Mediterranean diet (treatment effect −15.6 [-24.6 to −6.6]; p = 0.001 and −14.8 [-23.5 to −6.2]; p = 0.001, respectively); systolic and diastolic blood pressure decreased 9.3 and 7.3 mmHg on the Mediterranean diet, compared with 3.4 and 4.1 mmHg on the vegan diet (treatment effect +5.9 [95% CI +1.0 to +10.9]; p = 0.02; and +1.8 [95% CI −4.6 to +8.1]; p = 0.58, respectively). Conclusions: A low-fat vegan diet improved body weight, lipid concentrations, and insulin sensitivity, both from baseline and compared with a Mediterranean diet. Blood pressure decreased on both diets, more on the Mediterranean diet. Clinical trial registration: number, NCT03698955
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The carbohydrate–insulin model of obesity posits that high-carbohydrate diets lead to excess insulin secretion, thereby promoting fat accumulation and increasing energy intake. Thus, low-carbohydrate diets are predicted to reduce ad libitum energy intake as compared to low-fat, high-carbohydrate diets. To test this hypothesis, 20 adults aged 29.9 ± 1.4 (mean ± s.e.m.) years with body mass index of 27.8 ± 1.3 kg m⁻² were admitted as inpatients to the National Institutes of Health Clinical Center and randomized to consume ad libitum either a minimally processed, plant-based, low-fat diet (10.3% fat, 75.2% carbohydrate) with high glycemic load (85 g 1,000 kcal⁻¹) or a minimally processed, animal-based, ketogenic, low-carbohydrate diet (75.8% fat, 10.0% carbohydrate) with low glycemic load (6 g 1,000 kcal⁻¹) for 2 weeks followed immediately by the alternate diet for 2 weeks. One participant withdrew due to hypoglycemia during the low-carbohydrate diet. The primary outcomes compared mean daily ad libitum energy intake between each 2-week diet period as well as between the final week of each diet. We found that the low-fat diet led to 689 ± 73 kcal d⁻¹ less energy intake than the low-carbohydrate diet over 2 weeks (P < 0.0001) and 544 ± 68 kcal d⁻¹ less over the final week (P < 0.0001). Therefore, the predictions of the carbohydrate–insulin model were inconsistent with our observations. This study was registered on as NCT03878108.
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Objective To determine the efficacy and safety of low carbohydrate diets (LCDs) and very low carbohydrate diets (VLCDs) for people with type 2 diabetes. Design Systematic review and meta-analysis. Data sources Searches of CENTRAL, Medline, Embase, CINAHL, CAB, and grey literature sources from inception to 25 August 2020. Study selection Randomized clinical trials evaluating LCDs (<130 g/day or <26% of a 2000 kcal/day diet) and VLCDs (<10% calories from carbohydrates) for at least 12 weeks in adults with type 2 diabetes were eligible. Data extraction Primary outcomes were remission of diabetes (HbA 1c <6.5% or fasting glucose <7.0 mmol/L, with or without the use of diabetes medication), weight loss, HbA 1c , fasting glucose, and adverse events. Secondary outcomes included health related quality of life and biochemical laboratory data. All articles and outcomes were independently screened, extracted, and assessed for risk of bias and GRADE certainty of evidence at six and 12 month follow-up. Risk estimates and 95% confidence intervals were calculated using random effects meta-analysis. Outcomes were assessed according to a priori determined minimal important differences to determine clinical importance, and heterogeneity was investigated on the basis of risk of bias and seven a priori subgroups. Any subgroup effects with a statistically significant test of interaction were subjected to a five point credibility checklist. Results Searches identified 14 759 citations yielding 23 trials (1357 participants), and 40.6% of outcomes were judged to be at low risk of bias. At six months, compared with control diets, LCDs achieved higher rates of diabetes remission (defined as HbA 1c <6.5%) (76/133 (57%) v 41/131 (31%); risk difference 0.32, 95% confidence interval 0.17 to 0.47; 8 studies, n=264, I ² =58%). Conversely, smaller, non-significant effect sizes occurred when a remission definition of HbA 1c <6.5% without medication was used. Subgroup assessments determined as meeting credibility criteria indicated that remission with LCDs markedly decreased in studies that included patients using insulin. At 12 months, data on remission were sparse, ranging from a small effect to a trivial increased risk of diabetes. Large clinically important improvements were seen in weight loss, triglycerides, and insulin sensitivity at six months, which diminished at 12 months. On the basis of subgroup assessments deemed credible, VLCDs were less effective than less restrictive LCDs for weight loss at six months. However, this effect was explained by diet adherence. That is, among highly adherent patients on VLCDs, a clinically important reduction in weight was seen compared with studies with less adherent patients on VLCDs. Participants experienced no significant difference in quality of life at six months but did experience clinically important, but not statistically significant, worsening of quality of life and low density lipoprotein cholesterol at 12 months. Otherwise, no significant or clinically important between group differences were found in terms of adverse events or blood lipids at six and 12 months. Conclusions On the basis of moderate to low certainty evidence, patients adhering to an LCD for six months may experience remission of diabetes without adverse consequences. Limitations include continued debate around what constitutes remission of diabetes, as well as the efficacy, safety, and dietary satisfaction of longer term LCDs. Systematic review registration PROSPERO CRD42020161795.
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Importance Excess body weight and insulin resistance lead to type 2 diabetes and other major health problems. There is an urgent need for dietary interventions to address these conditions. Objective To measure the effects of a low-fat vegan diet on body weight, insulin resistance, postprandial metabolism, and intramyocellular and hepatocellular lipid levels in overweight adults. Design, Setting, and Participants This 16-week randomized clinical trial was conducted between January 2017 and February 2019 in Washington, DC. Of 3115 people who responded to flyers in medical offices and newspaper and radio advertisements, 244 met the participation criteria (age 25 to 75 years; body mass index of 28 to 40) after having been screened by telephone. Interventions Participants were randomized in a 1:1 ratio. The intervention group (n = 122) was asked to follow a low-fat vegan diet and the control group (n = 122) to make no diet changes for 16 weeks. Main Outcomes and Measures At weeks 0 and 16, body weight was assessed using a calibrated scale. Body composition and visceral fat were measured by dual x-ray absorptiometry. Insulin resistance was assessed with the homeostasis model assessment index and the predicted insulin sensitivity index (PREDIM). Thermic effect of food was measured by indirect calorimetry over 3 hours after a standard liquid breakfast (720 kcal). In a subset of participants (n = 44), hepatocellular and intramyocellular lipids were quantified by proton magnetic resonance spectroscopy. Repeated measure analysis of variance was used for statistical analysis. Results Among the 244 participants in the study, 211 (87%) were female, 117 (48%) were White, and the mean (SD) age was 54.4 (11.6) years. Over the 16 weeks, body weight decreased in the intervention group by 5.9 kg (95% CI, 5.0-6.7 kg; P < .001). Thermic effect of food increased in the intervention group by 14.1% (95% CI, 6.5-20.4; P < .001). The homeostasis model assessment index decreased (−1.3; 95% CI, −2.2 to −0.3; P < .001) and PREDIM increased (0.9; 95% CI, 0.5-1.2; P < .001) in the intervention group. Hepatocellular lipid levels decreased in the intervention group by 34.4%, from a mean (SD) of 3.2% (2.9%) to 2.4% (2.2%) (P = .002), and intramyocellular lipid levels decreased by 10.4%, from a mean (SD) of 1.6 (1.1) to 1.5 (1.0) (P = .03). None of these variables changed significantly in the control group over the 16 weeks. The change in PREDIM correlated negatively with the change in body weight (r = −0.43; P < .001). Changes in hepatocellular and intramyocellular lipid levels correlated with changes in insulin resistance (both r = 0.51; P = .01). Conclusions and Relevance A low-fat plant-based dietary intervention reduces body weight by reducing energy intake and increasing postprandial metabolism. The changes are associated with reductions in hepatocellular and intramyocellular fat and increased insulin sensitivity. Trial Registration Identifier: NCT02939638
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Importance Higher Mediterranean diet (MED) intake has been associated with reduced risk of type 2 diabetes, but underlying biological mechanisms are unclear. Objective To characterize the relative contribution of conventional and novel biomarkers in MED-associated type 2 diabetes risk reduction in a US population. Design, Setting, and Participants This cohort study was conducted among 25 317 apparently healthy women. The participants with missing information regarding all traditional and novel metabolic biomarkers or those with baseline diabetes were excluded. Participants were invited for baseline assessment between September 1992 and May 1995. Data were collected from November 1992 to December 2017 and analyzed from December 2018 to December 2019. Exposures MED intake score (range, 0 to 9) was computed from self-reported dietary intake, representing adherence to Mediterranean diet intake. Main Outcomes and Measures Incident cases of type 2 diabetes, identified through annual questionnaires; reported cases were confirmed by either telephone interview or supplemental questionnaire. Proportion of reduced risk of type 2 diabetes explained by clinical risk factors and a panel of 40 biomarkers that represent different physiological pathways was estimated. Results The mean (SD) age of the 25 317 female participants was 52.9 (9.9) years, and they were followed up for a mean (SD) of 19.8 (5.8) years. Higher baseline MED intake (score ≥6 vs ≤3) was associated with as much as a 30% lower type 2 diabetes risk (age-adjusted and energy-adjusted hazard ratio, 0.70; 95% CI, 0.62-0.79; when regression models were additionally adjusted with body mass index [BMI]: hazard ratio, 0.85; 95% CI, 0.76-0.96). Biomarkers of insulin resistance made the largest contribution to lower risk (accounting for 65.5% of the MED–type 2 diabetes association), followed by BMI (55.5%), high-density lipoprotein measures (53.0%), and inflammation (52.5%), with lesser contributions from branched-chain amino acids (34.5%), very low-density lipoprotein measures (32.0%), low-density lipoprotein measures (31.0%), blood pressure (29.0%), and apolipoproteins (23.5%), and minimal contribution (≤2%) from hemoglobin A1c. In post hoc subgroup analyses, the inverse association of MED diet with type 2 diabetes was seen only among women who had BMI of at least 25 at baseline but not those who had BMI of less than 25 (eg, women with BMI <25, age- and energy-adjusted HR for MED score ≥6 vs ≤3, 1.01; 95% CI, 0.77-1.33; P for trend = .92; women with BMI ≥25: HR, 0.76; 95% CI, 0.67-0.87; P for trend < .001). Conclusions and Relevance In this cohort study, higher MED intake scores were associated with a 30% relative risk reduction in type 2 diabetes during a 20-year period, which could be explained in large part by biomarkers of insulin resistance, BMI, lipoprotein metabolism, and inflammation.
The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction ( Readers who wish to comment on the Standards of Care are invited to do so at
The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction ( Readers who wish to comment on the Standards of Care are invited to do so at
The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction ( Readers who wish to comment on the Standards of Care are invited to do so at
Aims: To provide global estimates of diabetes prevalence for 2019 and projections for 2030 and 2045. Methods: A total of 255 high-quality data sources, published between 1990 and 2018 and representing 138 countries were identified. For countries without high quality in-country data, estimates were extrapolated from similar countries matched by economy, ethnicity, geography and language. Logistic regression was used to generate smoothed age-specific diabetes prevalence estimates (including previously undiagnosed diabetes) in adults aged 20-79 years. Results: The global diabetes prevalence in 2019 is estimated to be 9.3% (463 million people), rising to 10.2% (578 million) by 2030 and 10.9% (700 million) by 2045. The prevalence is higher in urban (10.8%) than rural (7.2%) areas, and in high-income (10.4%) than low-income countries (4.0%). One in two (50.1%) people living with diabetes do not know that they have diabetes. The global prevalence of impaired glucose tolerance is estimated to be 7.5% (374 million) in 2019 and projected to reach 8.0% (454 million) by 2030 and 8.6% (548 million) by 2045. Conclusions: Just under half a billion people are living with diabetes worldwide and the number is projected to increase by 25% in 2030 and 51% in 2045.
Background and objectives: The association between plant-based diets, incident CKD, and kidney function decline has not been examined in the general population. We prospectively investigated this relationship in a population-based study, and evaluated if risk varied by different types of plant-based diets. Design, setting, participants, & measurements: Analyses were conducted in a sample of 14,686 middle-aged adults enrolled in the Atherosclerosis Risk in Communities study. Diets were characterized using four plant-based diet indices. In the overall plant-based diet index, all plant foods were positively scored; in the healthy plant-based diet index, only healthful plant foods were positively scored; in the provegetarian diet, selected plant foods were positively scored. In the less healthy plant-based diet index, only less healthful plant foods were positively scored. All indices negatively scored animal foods. We used Cox proportional hazards models to study the association with incident CKD and linear mixed models to examine decline in eGFR, adjusting for confounders. Results: During a median follow-up of 24 years, 4343 incident CKD cases occurred. Higher adherence to a healthy plant-based diet (HR comparing quintile 5 versus quintile 1 [HRQ5 versus Q1], 0.86; 95% confidence interval [95% CI], 0.78 to 0.96; P for trend =0.001) and a provegetarian diet (HRQ5 versus Q1, 0.90; 95% CI, 0.82 to 0.99; P for trend =0.03) were associated with a lower risk of CKD, whereas higher adherence to a less healthy plant-based diet (HRQ5 versus Q1, 1.11; 95% CI, 1.01 to 1.21; P for trend =0.04) was associated with an elevated risk. Higher adherence to an overall plant-based diet and a healthy plant-based diet was associated with slower eGFR decline. The proportion of CKD attributable to lower adherence to healthy plant-based diets was 4.1% (95% CI, 0.6% to 8.3%). Conclusions: Higher adherence to healthy plant-based diets and a vegetarian diet was associated with favorable kidney disease outcomes.