ArticlePDF Available

A Call for an End to the Diet Debates

August 2013
JAMA The Journal of the American Medical Association 310(7):687-8

DOI:10.1001/jama.2013.8601

Source
PubMed

Authors:

Sherry Pagoto

University of Massachusetts Chan Medical School

Brad Appelhans

Rush University Medical Center

This commentary published in the Journal of the American Medical Association calls for an end to the “diet debates" in the scientific community and reported in the media.

Content uploaded by Brad Appelhans

Content may be subject to copyright.

A Call for an End to the Diet Debates

As the obesity epidemic persists, the time has come

to end the pursuit of the “ideal” diet for weight loss and

disease prevention. The dietary debate in the scientific

community and reported in the media about the opti-

mal macronutrient-focused weight loss diet sheds little

light on the treatment of obesity and may mislead the

public regarding proper weight management . Numer-

ous randomized trials comparing diets differing in mac-

ronutrient compositions (eg, low-carbohydrate, low-

fat, Mediterranean) have demonstrated differences in

weight loss and metabolic risk factors that are small (ie,

a mean difference of <1 kg) and inconsistent. In the past

year alone, 4 meta-analyses of diet comparison studies

have been published, each summarizing 13 to 24

trials.

1-4

The only consistent finding among the trials is

that adherence—the degree to which participants con-

tinued in the program or met program goals for diet

and physical ac tivity—was most strongly associated

with weight loss and improvement in disease-related

outcomes. The long history of trials showing very mod-

est differences suggests that additional trials compar-

ing diets varying in macronutrient content most likely

will not produce finding s that would significantly

advance the science of obesity. Progress in obesity

management will require greater understanding of the

biological, behavioral, and environmental factors asso-

ciated with adherence to lifestyle changes including

both diet and physical activity.

Macronutrient content may influence dietary ad-

herence via the satiating properties of protein, carbo-

hydrates, and fat. However, dietary content is only one

of many factors inf luencing adherence. The assump-

tion that one diet is optimal for all persons is counter-

productive because this assumption ignores the varia-

tion in adherence inf luenced by food preferences,

cultural or regional traditions, food availability, and food

intolerances. These are independent of direct physi-

ological effects of macronutrient composition on weight

loss. The most important question is how to improve be-

havioral adherence.

There are 2 reasons the diet debates persist. First,

the commercialization potential of breakthrough diets

is substantial. Fad diets have created a multibillion-

dollar industry. The difference between fad diets is al-

most entirely related to macronutrient composition (eg,

Zone, Atkins, South Beach, Dukan, Paleo). A second fac-

tor is the assumption that lifestyle interventions are in-

effective. Poor adherence (and consequent weight re-

gain) following the intervention is cited as evidence that

these interventions do not work.

This conclusion can

be challenged because it assumes a definition for effi-

cacy more stringent than that applied to other forms of

preventive care.

Termination of treatment or nonadherence almost

always results in reduced benefit. The effects of choles-

terol-lowering agents, hypertension drugs, and diabe-

tes medications do not have long-lastingeffects after pa-

tients stop taking them, with effects declining within a

matter of hours (eg, metformin) to months (eg, statins).

Just like medical therapies, behavioral interven-

tions should only be expected to be effective when treat-

ment is active. That lifestyle interventions are viewed as

ineffective is especially surprising given that 3 large long-

term trials demonstrated that the effects of a lifestyle in-

tervention on diabetes prevention are actually sus-

tained long after the intervention ends.

6-8

The Finnish

Diabetes Prevention Study compared a 4-year lifestyle

intervention with health education and

found a reduction in diabetes incidence

for as long as 13 years,

9 years after the

active intervention ended. The China Da

Qing Diabetes Prevention Study showed

that a 6-year lifestyle intervention more

effectively reduced diabetes risk than a

control group for 20 years,

14 years af-

ter the intervention ended. The Diabe-

tes Prevention Program compared a life-

style intervention with metformin and

placebo, but exposed the latter 2 groups to the lifestyle

intervention 3 years into the study.

Even though all

groups eventually received some amount of lifestyle in-

tervention, at 10 years the cumulative incidence of dia-

betes was lowest in the lifestyle intervention group; this

intervention delayed onset of diabetes by 4 years rela-

tive to 2 years in the metformin group. Current efforts

need to understand the common factors of these trials,

all of which involved multipronged interventions involv-

ing dietary and exercise counseling and behavioralmodi-

fication. The pursuit of the ideal macronutrient content

diet is unidimensional, ignoring 2 of the 3 major com-

ponents of standard lifestyle interventions: behavioral

modification and exercise. To consider lifestyle inter-

ventions as diets ignores their complexity, with behav-

ioral modif ication as the piece that specifically ad-

dresses adherence.

Another important research question is how to im-

prove the scalability of lifestyle interventions. Despite

the evidence, lifestyle interventions may havebeenused

sparingly in clinical practice because reimbursement is

The ongoing diet debates expose the

public to mixed messages emanating

from various trials that have yielded

little but have heavily reinforced a fad

diet industry

VIEWPOINT

Sherry L. Pagoto, PhD

University of

Massachusetts Medical

School, Worcester.

Bradley M. Appelhans,

PhD

Rush University

Medical Center,

Chicago, Illinois.

Author Reading at

jama.com

Corresponding

Author: Sherry L.

Pagoto, PhD, Division

of Preventive and

Behavioral Medicine,

Department of

Medicine, University of

Massachusetts Medical

School, 55 Lake Ave N,

Worcester, MA 01655

(sherry.pagoto

@umassmed.edu).

jama.com JAMA August 21, 2013 Volume 310, Number 7 687

Downloaded From: http://jama.jamanetwork.com/ by a Rush University User on 08/20/2013

inadequate. In December 2011, the Centers for Medicare & Medic-

aid Services (CMS) announced that it would reimburse lifestyle in-

terventions but limited this cover agetoprimarycarephysicians,phy -

sician assistants, and nurse practitioners. The restriction to primary

care practitioners will limit implementation of lifestyle interven-

tions because primary care practitioners are not usually familiar with

behavioral counseling for weight loss. These clinicians also may not

have the time or resources to deliver intensive lifestyle inter ven-

tions, as evidenced by a recent steady decline in obesity counsel-

ing by primary care physicians.

The number and duration of visits

that will be reimbursed by CMS are also less than that studied in clini-

cal trials.

In a shrinking funding environment for both health care and

research, it is puzzling that the diet debate continues when lifestyle

interventions with well-established long-term efficacy are available

but have not received the necessary support to be widely imple-

mented. The ongoing diet debates expose the public to mixed

messages emanating from various trials that have yielded little but

have heavily reinforced a fad diet industry that derives billions of

dollars from a nation that is not getting healthier. Because behav-

ioral adherence is much more important than diet composition, the

best approach is to counsel patients to choose a dietary plan they

find easiest to adhere to in the long term. Patients should develop

an appropriate physical activity program and learn behavioral

modification to promote long-term adherence. Although research

specifically focused on improving adherence is ongoing, the num-

ber of studies being conducted is small compared with head-to-

head macronutrient-focused diet comparison studies. Advancing

obesity treatment requires emphasis on the biological, behavioral,

and environmental factors inf luencing adherence to lifestyle

changes and developing reimbursement strategies to support life-

style interventions.

ARTICLE INFORMATION

Conflict of Interest Disclosures: The authors have

completed and submitted the ICMJE Form for

Disclosure of Potential Conflicts of Interest. Dr

Pagoto reported that she is on the Advisory Board

of Mobile Wellbeing Inc.

REFERENCES

1. Ajala O, English P, Pinkney J. Systematic review

and meta-analysis of different dietary approaches

to the management of type 2 diabetes. Am J Clin

Nutr. 2013;97(3):505-516.

2. Wycherley TP, Moran LJ, Clifton PM, Noakes M,

Brinkworth GD. Effects of energy-restricted

high-protein, low-fat compared with

standard-protein, low-fat diets: a meta-analysis of

randomized controlled trials. Am J Clin Nutr.

2012;96(6):1281-1298.

3. Hu T, Mills KT, Yao L , et al. Effects of

low-carbohydrate diets versus low-fat diets on

metabolic risk factors: a meta-analysis of

randomized controlled clinical trials. Am J

Epidemiol. 2012;176(suppl 7):S44-S54.

4. Bueno NB, de Melo IS, de Oliveira SL, da Rocha

Ataide T. Very-low-carbohydrate ketogenic diet v.

low-fat diet for long-term weight loss: a

meta-analysis of randomised controlled trials

[published online May 7, 2013]. Br J Nutr. 2013;1-10.

5. Bacon L, Aphramor L. Weight science: evaluating

the evidence for a paradigm shift [published online

January 24, 2011]. Nutr J. doi:10.1186/1475-2891-

10-9.

6. Lindström J, Peltonen M, Eriksson JG, et al;

Finnish Diabetes Prevention Study (DP S). Improved

lifestyle and decreased diabetes risk over 13 years:

long-term follow-up of the randomised Finnish

Diabetes Prevention Study (DPS). Diabetologia.

2013;56(2):284-293.

7. Knowler WC, Fowler SE, Hamman RF, et al;

Diabetes Prevention Program Research Group.

10-year follow-up of diabetes incidence and weight

loss in the Diabetes Prevention Program Outcomes

Study. Lancet. 2009;374(9702):1677-1686.

8. Li G, Zhang P, Wang J, et al. The long-term effect

of lifestyle interventions to prevent diabetes in the

China Da Qing Diabetes Prevention Study: a

20-year follow-up study. Lancet. 2008;371(9626):

1783-1789.

9. Kraschnewski JL, Sciamanna CN, Stuckey HL,

et al. A silent response to the obesity epidemic:

decline in US physician weight counseling. Med

Care. 2013;51(2):186-192.

Opinion Viewpoint

688 JAMA August 21, 2013 Volume 310, Number 7 jama.com

Downloaded From: http://jama.jamanetwork.com/ by a Rush University User on 08/20/2013

The Effect of Individual Attitude toward Healthy Nutrition on Adherence to a High-UFA and High-Protein Diet: Results of a Randomized Controlled Trial

Article

Full-text available

Sep 2024

Despite beneficial cardiovascular effects, substantial long-term modulation of food pattern could only be achieved in a limited number of participants. The impact of attitude towards healthy nutrition (ATHN) on successful modulation of dietary behavior is unclear, especially in the elderly. We aimed to analyze whether the personal ATHN influences 12-month adherence to two different dietary intervention regimes within a 36-month randomized controlled trial. Methods: 502 subjects were randomized to an intervention group (IG; dietary pattern focused on high intake of unsaturated fatty acids (UFA), plant protein and fiber) or control group (CG; dietary recommendation in accordance with the German Society of Nutrition) within a 36-month dietary intervention trial. Sum scores for effectiveness, appreciation and practice of healthy nutrition were assessed using ATHN questionnaire during the trial (n = 344). Linear regression models were used to investigate associations between ATHN and dietary patterns at baseline and at month 12. Results: Retirement, higher education level, age and lower body mass index (BMI) were associated with higher ATHN sum scores. ATHN was similar in CG and IG. Higher baseline intake of polyunsaturated fatty acids (PUFA) and fiber as well as lower intake in saturated fatty acids (SFA) were associated with higher scores in practice in both groups. The intervention resulted in a stronger increase of UFA, protein and fiber in the IG after 12 months, while intake of SFA declined (p < 0.01). Higher scores in appreciation were significantly associated with higher intake of fiber and lower intake of SFA in the CG at month 12, whereas no associations between ATHN and macronutrient intake were observed in the IG after 12 months. Conclusions: While ATHN appeared to play a role in general dietary behavior, ATHN did not affect the success of the specific dietary intervention in the IG at month 12. Thus, the dietary intervention achieved a substantial modification of dietary pattern in the IG and was effective to override the impact of the individual ATHN on dietary behavior.

Adherence and eating experiences differ between participants following a flexitarian diet including red meat or a vegetarian diet including plant-based meat alternatives: findings from a 10-week randomised dietary intervention trial

Article

Full-text available

Jun 2023

Background Flexitarian, vegetarian and exclusively plant-based diets are increasingly popular, particularly amongst young adults. This is the first randomised dietary intervention to investigate the health, wellbeing, and behavioural implications of consuming a basal vegetarian diet that additionally includes low-to-moderate amounts of red meat (flexitarian) compared to one containing plant-based meat alternatives (PBMAs, vegetarian) in young adults (ClinicalTrials.gov NCT04869163). The objective for the current analysis is to measure adherence to the intervention, nutrition behaviours, and participants’ experience with their allocated dietary group. Methods Eighty healthy young adults participated in this 10-week dietary intervention as household pairs. Household pairs were randomised to receive either approximately three serves of red meat (average of 390 g cooked weight per individual, flexitarian group) or PBMAs (350–400 g per individual, vegetarian group) per week on top of a basal vegetarian diet. Participants were supported to adopt healthy eating behaviours, and this intervention was developed and implemented using a behaviour change framework. Adherence (eating allocated red meat or PBMA, abstaining from animal-based foods not provided by researchers) was continuously monitored, with total scores calculated at the end of the 10-week intervention period. Eating experiences were measured by the Positive Eating Scale and a purpose-designed exit survey, and a food frequency questionnaire measured dietary intake. Analyses used mixed effects modeling taking household clustering into account. Results The total average adherence score was 91.5 (SD = 9.0) out of a possible 100, with participants in the flexitarian group scoring higher (96.1, SD = 4.6, compared to 86.7, SD = 10.0; p < 0.001). Those receiving red meat were generally more satisfied with this allocation compared to those receiving the PBMAs, even though a leading motivation for participants joining the study was an opportunity to try plant-based eating (35% expressed that their interest in taking part was related to trying plant-based eating). Participants in both intervention groups had increased vegetable intake (p < 0.001), and reported more positive eating experiences (p = 0.020) and satisfaction with eating (p = 0.021) at the end of the 10-week intervention relative to baseline values. Conclusion Methods to encourage engagement with the trial were successful, as participants demonstrated excellent adherence to the intervention. Observed differences in participants’ adherence and experiences between flexitarian and vegetarian groups holds implications for the adoption of healthy, sustainable dietary patterns beyond this study alone.

Efficacy of the Aim2Be Intervention in Changing Lifestyle Behaviors Among Adolescents With Overweight and Obesity: Randomized Controlled Trial

Article

Full-text available

Apr 2023
J MED INTERNET RES

Background Aim2Be is a gamified lifestyle app designed to promote lifestyle behavior changes among Canadian adolescents and their families. Objective The primary aim was to test the efficacy of the Aim2Be app with support from a live coach to reduce weight outcomes (BMI Z score [zBMI]) and improve lifestyle behaviors among adolescents with overweight and obesity and their parents versus a waitlist control group over 3 months. The secondary aim was to compare health trajectories among waitlist control participants over 6 months (before and after receiving access to the app), assess whether support from a live coach enhanced intervention impact, and evaluate whether the app use influenced changes among intervention participants. MethodsA 2-arm parallel randomized controlled trial was conducted from November 2018 to June 2020. Adolescents aged 10 to 17 years with overweight or obesity and their parents were randomized into an intervention group (Aim2Be with a live coach for 6 months) or a waitlist control group (Aim2Be with no live coach; accessed after 3 months). Adolescents’ assessments at baseline and at 3 and 6 months included measured height and weight, 24-hour dietary recalls, and daily step counts measured with a Fitbit. Data on self-reported physical activity, screen time, fruit and vegetable intake, and sugary beverage intake of adolescents and parents were also collected. ResultsA total of 214 parent-child participants were randomized. In our primary analyses, there were no significant differences in zBMI or any of the health behaviors between the intervention and control groups at 3 months. In our secondary analyses, among waitlist control participants, zBMI (P=.02), discretionary calories (P=.03), and physical activity outside of school (P=.001) declined, whereas daily screen time increased (P

Health effects of the time-restricted eating in adults with obesity: A systematic review and meta-analysis

Article

Full-text available

Feb 2023

Background The number of people suffering from overweight or obesity has been steadily increasing in recent years. As a new form of diet, the efficacy of time-restricted eating (TRE) remains debatable. Objective This meta-analysis quantified the effect of TRE on weight change and other physical parameters in obese and overweight adults. Methods We did a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing the TRE interventions on weight loss and other metabolic parameters by searching PubMed, Embase, and Cochrane Central Register of Controlled Trials to identify eligible trials published from database inception up until 23 August 2022. The risk of bias was assessed using the Revised Cochrane risk-of-bias tool (ROB-2.0). Meta-analysis was performed using Review Manager 5.4.1 software. Results Nine RCTs with 665 individuals (345 in the TRE group while 320 in the control group) were included. Results indicated that TRE had a greater decrease in body weight (−1.28 kg; 95% CI [−2.05, −0.52], p = 0.001), fat mass (−0.72 kg; 95% CI [−1.40, −0.03], p = 0.04), body mass index (−0.34 kg/m²; 95% CI [−0.64, −0.04], p = 0.03) and diastolic blood pressure (−2.26 mmHg 95% CI [−4.02, −0.50], p = 0.01). However, the meta-analysis demonstrated that there was no significant difference between TRE and the control group in lean mass, systolic blood pressure, waist circumference, fasting glucose, fasting insulin, homeostasis model assessment-insulin resistance (HOMA-IR), total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides. Besides, the duration of the study and daily eating window also had an impact on weight change. Conclusion TRE was associated with reductions in weight and fat mass and can be a dietary intervention option for adults with obesity. But high-quality trials and longer follow-ups are needed to draw definitive conclusions.

Comparative study of time-restricted eating on body composition and metabolic parameters in climacteric women with obesity: analysis of a pre-post intervention

Article

Feb 2025

Objective The physiological changes inherent to the climacteric period can trigger or aggravate overweight/obesity, among several other health disorders. This study aimed to evaluate the effects of time-restricted eating (TRE) on body composition and cardiometabolic parameters in climacteric women with obesity submitted to caloric restriction (CR) through a hypocaloric diet. Methods We conducted an analysis of a clinical trial in a pre-post design that included adult climacteric women with obesity. Participants were divided into two groups: hypocaloric diet control group (n = 30) — with hypocaloric diet and free meal times, and hypocaloric diet and time-restricted eating group (HTRE) (n = 27) — with hypocaloric diet and TRE (fasting from 7 pm to 7 am ), for 10 weeks. Anthropometric and biochemical parameters were evaluated before and after the intervention period. A significance level of P < 0.05 was considered for all cases. Results Both groups showed a reduction in all anthropometric parameters, but without significant difference ( P = 0.34) between groups. However, some metabolic parameters were significantly highlighted in the HTRE such as cholesterol level normalization (HTRE, 181.76 ± 34.20 mg/dL) and a decrease in plasma atherogenicity ( P = 0.02), glycated hemoglobin ( P < 0.001), estimated mean glucose ( P = 0.02), and alanine aminotransferase ( P = 0.02), unlike the hypocaloric diet control group, which did not show such significance. Conclusions In this study, from the perspective of body composition, similar changes were observed between the group subjected to CR alone and the group subjected to CR combined with a 12-hour overnight fast. However, there was an indication of superior improvement in glycemic and lipid parameters in the group subjected to the 12-hour overnight fast. These findings suggest the potential for TRE, as implemented, to have positive effects on reducing cardiovascular risk and other chronic metabolic diseases.

The Role of the Behavioral Health Provider in the Management of the Patient Seeking Metabolic and Bariatric Surgery

Chapter

Jan 2024

Obesity management requires a multidisciplinary team in order to properly assess and treat patients with obesity. In addition to the medical comorbidities associated with obesity, psychosocial factors could affect long-term outcomes beyond weight loss. Research on predictive psychosocial factors continues to be inconsistent, but common findings suggest that psychiatric disorders, cognitive functioning, personality factors, and eating pathology can affect both short- and long-term outcomes of metabolic and bariatric surgery. Although a comprehensive psychosocial evaluation is the standard of practice for patients seeking metabolic and bariatric surgery, practice standards have not been defined for these evaluations. This chapter aims to describe the role of the behavioral health provider, and the goals of the presurgical psychosocial evaluation and will identify and discuss general domains that should be included in the clinical interview, as well as other considerations. Information obtained during the clinical interview is key for assessing a patient’s readiness for surgery and for improving postsurgical outcomes. Thus, in addition to reviewing the role of the behavioral health provider in conducting the presurgical evaluations, this chapter will also describe their role in facilitating psychosocial interventions in the preoperative phase as well as providing long-term care for patients with postoperative issues.

Long-Term Randomized Controlled Trials of Diet Intervention Reports and Their Impact on Cancer: A Systematic Review

Article

Full-text available

Sep 2024

Simple Summary Lifestyle dietary changes implemented by people who are overweight or obese to improve health generally focus on caloric restriction, changes in macronutrient intake, or both. Findings from reports of the impact of these changes on cancer are mixed, with many subjected to secondary analysis bias. An impact on cancer endpoints requires long-term (≥1 year) intervention. There is a clear need for more reports evaluating the role of diet in cancer risk reduction in overweight/obese individuals who are at increased risk of obesity-related cancers, especially reports focusing on cancers other than breast. Pharmacologic and metabolic/bariatric surgery-MBS strategies have demonstrated promise to deliver both greater initial weight loss and better weight loss maintenance). The impact of weight loss on reducing cancer risk may depend on the (1) amount and (2) maintenance of weight loss. Abstract Background: Most randomized controlled trials (RCTs) assessing the impact of diet on cancer have been short term (<1 year), mostly evaluating breast cancer survivors. Given the many-year interval that is generally required for an intervention to have an impact on cancer risk or prognosis, as well as the fact that lifestyle strategies such as diet modification frequently fail due to lack of adherence over the long term, we focused this systematic review only on longer-term (≥1 year) intervention reports. Diet intervention reports focused on reducing cancer risk in overweight and obese individuals target caloric restriction (every day, some days, or most hours of each day). Methods: This study is a systematic review of RCTs lasting at least 1 year, testing dietary interventions with a primary or secondary endpoint of cancer or a biomarker linked to cancer. Results: Fifty-one reports met our review criteria. Twenty of fifty-one (39%) reports are RCTs where the primary endpoint was cancer or a cancer-related biomarker, while the other reports evaluated reports where cancer or a cancer-related biomarker was a secondary endpoint. Thirteen of twenty (65%) primary reports evaluated isocaloric, and the remaining eight evaluated low-calorie diets. All but one of the primary and two secondary isocaloric diet reports evaluated the benefit of a low-fat diet (LFD), with the other three evaluating a Mediterranean diet (MedD). More LCD vs. isocaloric diet primary reports (71% vs. 38%) demonstrated cancer or cancer-related biomarker benefit; the difference in chance of benefit with secondary reports was 85% for LCD vs. 73% for isocaloric diets. Three of three MedD reports demonstrated benefit. Sixty-nine percent (20/29) of the secondary reports came from two large reports: the WHI diet modification trial (15 secondary reports) and the polyp prevention trial (5 secondary reports). Nineteen of twenty-two (86%) primary reports enrolled only women, and three enrolled both men and women. No study that met our criteria enrolled only men, comprising 1447 men in total vs. 62,054 women. Fifteen of twenty (75%) primary reports focus on healthy women or women with breast cancer. Adherence findings are discussed when provided. Conclusions: More long-term RCTs evaluating cancer and cancer-related biomarker endpoints are needed, especially for cancers at sites other than the breast.

Self-identified strategies to manage intake of tempting foods: Cross-sectional and prospective associations with BMI and snack intake

Article

Full-text available

Mar 2024
PUBLIC HEALTH NUTR

Objectives Individuals often use self-directed strategies to manage intake of tempting foods, but what these strategies are and whether they are effective is not well understood. This study assessed the frequency of use and subjective effectiveness of self-directed strategies in relation to BMI and snack intake. Design A cross-sectional and prospective study with three timepoints (T1: baseline, T2: 3 months, T3: 3 years). At T1, demographics, frequency of use and subjective effectiveness of 41 identified strategies were assessed. At T2 and T3, current weight was reported, and at T2 frequency of snack intake was also recorded. Setting Online study in the UK. Participants Data from N=368 participants (M age =34.41 years; M BMI =25.06 kg/m ² ) was used for analysis at T1, N=170 (46.20% of the total sample) at T2 and N=51 (13.59%) at T3. Results Two strategy factors were identified via principal axis factoring: 1) Diet, exercise, reduction of temptations, and cognitive strategies, and 2) Planning, preparation and eating style. For strategy 1, frequency of use, but not subjective effectiveness, was positively related to BMI at T1. Subjective effectiveness predicted an increase in BMI from T1 and T2 to T3. No relationship to snack intake was found. For strategy 2, frequency of use was negatively related to BMI at T1. Neither frequency of use nor subjective effectiveness were related to changes in BMI over time, but subjective effectiveness was negatively correlated with unhealthy snack intake. Conclusion Self-directed strategies to reduce the intake of tempting foods are not consistently related to BMI or snack intake.

Maternal Diet Quality During Pregnancy and Offspring Hepatic Fat in Early Childhood: The Healthy Start Study

Article

Feb 2023
J NUTR

Background: Overnutrition in utero may increase offspring risk of nonalcoholic fatty liver disease (NAFLD), but the specific contribution of maternal diet quality during pregnancy to this association remains understudied in humans. Objective: To examine associations of maternal diet quality during pregnancy with offspring hepatic fat in early childhood (median 5 years old, range 4-8 years old). Methods: Data were from 278 mother-child pairs in the longitudinal, Colorado-based Healthy Start Study. Multiple 24-hour recalls were collected from mothers during pregnancy (median 3 recalls, range 1 to 8 recalls starting after enrollment), and used to estimate maternal usual nutrient intakes and dietary pattern scores [Healthy Eating Index-2010 (HEI-2010), dietary inflammatory index (DII®), and relative Mediterranean diet score (rMED)]. Offspring hepatic fat was measured in early childhood by magnetic resonance imaging. Associations of maternal dietary predictors during pregnancy with offspring log-transformed hepatic fat were assessed by linear regression models adjusted for offspring demographics, maternal/perinatal confounders, and maternal total energy intake. Results: Higher maternal fiber intake and rMED scores during pregnancy were associated with lower offspring hepatic fat in early childhood in fully adjusted models [Back-transformed β (95% CI): 0.82 (0.72,0.94) per 5 g/1000 kcal fiber; 0.93 (0.88,0.99) per 1 SD for rMED]. In contrast, higher maternal total sugar and added sugar intakes, and DII scores were associated with higher offspring hepatic fat [Back-transformed β (95% CI): 1.18 (1.05,1.32) per 5% kcal/day added sugar; 1.08 (0.99, 1.18) per 1 SD for DII]. Analyses of dietary pattern sub-components also revealed associations of lower maternal intake of green vegetables and legumes and higher intakes of "empty calories" with higher offspring hepatic fat in early childhood. Conclusions: Poorer maternal diet quality during pregnancy was associated with greater offspring susceptibility to hepatic fat in early childhood. Our findings provide insights into potential perinatal targets for the primordial prevention of pediatric NAFLD.

Premeal almond load decreases postprandial glycaemia, adiposity and reversed prediabetes to normoglycemia: A randomized Controlled Trial

Article

Dec 2022

Background Asian Indians show rapid conversion from prediabetes to type 2 diabetes (T2D). Novel dietary strategies are needed to arrest this progression, by targeting postprandial hyperglycaemia (PPHG). Design We conducted a free-living randomized controlled open-label parallel arm study to evaluate the effect of a premeal load of almonds (20g) 30 minutes before major meals on anthropometric, glycaemic, and metabolic parameters over 3 months. Sixty-six participants with prediabetes in the age range of 18-60 yrs. were recruited. The study was registered at clinicaltrials.gov (registration no. NCT04769726). Results Thirty participants in each arm completed the study. As per ‘intention-to-treat’ analysis, overall additional mean reductions were statistically significant for body weight, BMI, waist circumference (WC), subscapular and suprailiac skinfolds, and improved handgrip strength (Kg) (p<0·001 for all) in the treatment arm vs. the control arm (after multiple adjustments). In the blood parameters, the additional mean reduction in the treatment arm vs. control arm was statistically significant for fasting and post-75 g oral glucose-load blood glucose, postprandial insulin, HOMA-IR, HbA1c, proinsulin, total cholesterol, and very low-density lipoprotein cholesterol (p<0·001for all). Most importantly, we observed a reversal to normoglycemic state (fasting blood glucose and 2h post-OGTT glucose levels) in 23.3% (7 out of 30) of participants in the treatment arm which is comparable to that seen with Acarbose (25%). Conclusion Incorporation of 20 g of almonds, 30 min before each major meal leads to significant improvement in body weight, WC, glycemia, and insulin resistance and shows potential for reversal of prediabetes to normal glucose regulation over 3 months.

Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: A meta-analysis of Randomised controlled trials

Article

Full-text available

May 2013
BRIT J NUTR

The role of very-low-carbohydrate ketogenic diets (VLCKD) in the long-term management of obesity is not well established. The present meta-analysis aimed to investigate whether individuals assigned to a VLCKD (i.e. a diet with no more than 50 g carbohydrates/d) achieve better long-term body weight and cardiovascular risk factor management when compared with individuals assigned to a conventional low-fat diet (LFD; i.e. a restricted-energy diet with less than 30 % of energy from fat). Through August 2012, MEDLINE, CENTRAL, ScienceDirect, Scopus, LILACS, SciELO, ClinicalTrials.gov and grey literature databases were searched, using no date or language restrictions, for randomised controlled trials that assigned adults to a VLCKD or a LFD, with 12 months or more of follow-up. The primary outcome was body weight. The secondary outcomes were TAG, HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), systolic and diastolic blood pressure, glucose, insulin, HbA1c and C-reactive protein levels. A total of thirteen studies met the inclusion/exclusion criteria. In the overall analysis, five outcomes revealed significant results. Individuals assigned to a VLCKD showed decreased body weight (weighted mean difference - 0·91 (95 % CI - 1·65, - 0·17) kg, 1415 patients), TAG (weighted mean difference - 0·18 (95 % CI - 0·27, - 0·08) mmol/l, 1258 patients) and diastolic blood pressure (weighted mean difference - 1·43 (95 % CI - 2·49, - 0·37) mmHg, 1298 patients) while increased HDL-C (weighted mean difference 0·09 (95 % CI 0·06, 0·12) mmol/l, 1257 patients) and LDL-C (weighted mean difference 0·12 (95 % CI 0·04, 0·2) mmol/l, 1255 patients). Individuals assigned to a VLCKD achieve a greater weight loss than those assigned to a LFD in the long term; hence, a VLCKD may be an alternative tool against obesity.

Effects of energy-restricted high-protein, low-fat compared with standard-protein, low-fat diets: A meta-analysis of randomized controlled trials

Article

Full-text available

Oct 2012
AM J CLIN NUTR

Background: It is currently unclear whether altering the carbohydrate-to-protein ratio of low-fat, energy-restricted diets augments weight loss and cardiometabolic risk markers. Objective: The objective was to conduct a systematic review and meta-analysis of studies that compared energy-restricted, isocaloric, high-protein, low-fat (HP) diets with standard-protein, low-fat (SP) diets on weight loss, body composition, resting energy expenditure (REE), satiety and appetite, and cardiometabolic risk factors. Design: Systematic searches were conducted by using MEDLINE, EMBASE, PubMed, and the Cochrane Central Register of Controlled Trials to identify weight-loss trials that compared isocalorically prescribed diets matched for fat intake but that differed in protein and carbohydrate intakes in participants aged ≥18 y. Twenty-four trials that included 1063 individuals satisfied the inclusion criteria. Results: Mean (±SD) diet duration was 12.1 ± 9.3 wk. Compared with an SP diet, an HP diet produced more favorable changes in weighted mean differences for reductions in body weight (−0.79 kg; 95% CI: −1.50, −0.08 kg), fat mass (FM; −0.87 kg; 95% CI: −1.26, −0.48 kg), and triglycerides (−0.23 mmol/L; 95% CI: −0.33, −0.12 mmol/L) and mitigation of reductions in fat-free mass (FFM; 0.43 kg; 95% CI: 0.09, 0.78 kg) and REE (595.5 kJ/d; 95% CI: 67.0, 1124.1 kJ/d). Changes in fasting plasma glucose, fasting insulin, blood pressure, and total, LDL, and HDL cholesterol were similar across dietary treatments (P ≥ 0.20). Greater satiety with HP was reported in 3 of 5 studies. Conclusion: Compared with an energy-restricted SP diet, an isocalorically prescribed HP diet provides modest benefits for reductions in body weight, FM, and triglycerides and for mitigating reductions in FFM and REE.

Improved lifestyle and decreased diabetes risk over 13 years: Long-term follow-up of the randomised Finnish Diabetes Prevention Study (DPS)

Article

Full-text available

Oct 2012
DIABETOLOGIA

Aims/hypothesis: This study aimed to determine whether lifestyle intervention lasting for 4 years affected diabetes incidence, body weight, glycaemia or lifestyle over 13 years among individuals at high risk of type 2 diabetes. Methods: Overweight, middle-aged men (n = 172) and women (n = 350) with impaired glucose tolerance were randomised in 1993-1998 to an intensive lifestyle intervention group (n = 265), aiming at weight reduction, dietary modification and increased physical activity, or to a control group (n = 257) that received general lifestyle information. The primary outcome was a diagnosis of diabetes based on annual OGTTs. Secondary outcomes included changes in body weight, glycaemia, physical activity and diet. After active intervention (median 4 years, range 1-6 years), participants still free of diabetes and willing to continue their participation (200 in the intervention group and 166 in the control group) were further followed until diabetes diagnosis, dropout or the end of 2009, with a median total follow-up of 9 years and a time span of 13 years from baseline. Results: During the total follow-up the adjusted HR for diabetes (intervention group vs control group) was 0.614 (95% CI 0.478, 0.789; p < 0.001). The corresponding HR during the post-intervention follow-up was 0.672 (95% CI 0.477, 0.947; p = 0.023). The former intervention group participants sustained lower absolute levels of body weight, fasting and 2 h plasma glucose and a healthier diet. Adherence to lifestyle changes during the intervention period predicted greater risk reduction during the total follow-up. Conclusions/interpretation: Lifestyle intervention in people at high risk of type 2 diabetes induces sustaining lifestyle change and results in long-term prevention of progression to type 2 diabetes.

Weight Science: Evaluating the Evidence for a Paradigm Shift

Article

Full-text available

Jan 2011
Nutr J

Current guidelines recommend that "overweight" and "obese" individuals lose weight through engaging in lifestyle modification involving diet, exercise and other behavior change. This approach reliably induces short term weight loss, but the majority of individuals are unable to maintain weight loss over the long term and do not achieve the putative benefits of improved morbidity and mortality. Concern has arisen that this weight focus is not only ineffective at producing thinner, healthier bodies, but may also have unintended consequences, contributing to food and body preoccupation, repeated cycles of weight loss and regain, distraction from other personal health goals and wider health determinants, reduced self-esteem, eating disorders, other health decrement, and weight stigmatization and discrimination. This concern has drawn increased attention to the ethical implications of recommending treatment that may be ineffective or damaging. A growing trans-disciplinary movement called Health at Every Size (HAES) challenges the value of promoting weight loss and dieting behavior and argues for a shift in focus to weight-neutral outcomes. Randomized controlled clinical trials indicate that a HAES approach is associated with statistically and clinically relevant improvements in physiological measures (e.g., blood pressure, blood lipids), health behaviors (e.g., eating and activity habits, dietary quality), and psychosocial outcomes (such as self-esteem and body image), and that HAES achieves these health outcomes more successfully than weight loss treatment and without the contraindications associated with a weight focus. This paper evaluates the evidence and rationale that justifies shifting the health care paradigm from a conventional weight focus to HAES.

The long-term effect of lifestyle interventions to prevent diabetes in the China Da Qing Diabetes Prevention Study: A 20-year follow-up study

Article

Full-text available

Jun 2008
LANCET

Intensive lifestyle interventions can reduce the incidence of type 2 diabetes in people with impaired glucose tolerance, but how long these benefits extend beyond the period of active intervention, and whether such interventions reduce the risk of cardiovascular disease (CVD) and mortality, is unclear. We aimed to assess whether intensive lifestyle interventions have a long-term effect on the risk of diabetes, diabetes-related macrovascular and microvascular complications, and mortality. In 1986, 577 adults with impaired glucose tolerance from 33 clinics in China were randomly assigned to either the control group or to one of three lifestyle intervention groups (diet, exercise, or diet plus exercise). Active intervention took place over 6 years until 1992. In 2006, study participants were followed-up to assess the long-term effect of the interventions. The primary outcomes were diabetes incidence, CVD incidence and mortality, and all-cause mortality. Compared with control participants, those in the combined lifestyle intervention groups had a 51% lower incidence of diabetes (hazard rate ratio [HRR] 0.49; 95% CI 0.33-0.73) during the active intervention period and a 43% lower incidence (0.57; 0.41-0.81) over the 20 year period, controlled for age and clustering by clinic. The average annual incidence of diabetes was 7% for intervention participants versus 11% in control participants, with 20-year cumulative incidence of 80% in the intervention groups and 93% in the control group. Participants in the intervention group spent an average of 3.6 fewer years with diabetes than those in the control group. There was no significant difference between the intervention and control groups in the rate of first CVD events (HRR 0.98; 95% CI 0.71-1.37), CVD mortality (0.83; 0.48-1.40), and all-cause mortality (0.96; 0.65-1.41), but our study had limited statistical power to detect differences for these outcomes. Group-based lifestyle interventions over 6 years can prevent or delay diabetes for up to 14 years after the active intervention. However, whether lifestyle intervention also leads to reduced CVD and mortality remains unclear.

Diabetes Prevention Program Research Group. 10-year follow-up of diabetes incidence and weight loss in the Diabetes Prevention Program Outcomes Study

Article

Jan 2009

Systematic review and meta-analysis of different dietary approaches to the management of type 2 diabetes

Article

Jan 2013
AM J CLIN NUTR

Background: There is evidence that reducing blood glucose concentrations, inducing weight loss, and improving the lipid profile reduces cardiovascular risk in people with type 2 diabetes. Objective: We assessed the effect of various diets on glycemic control, lipids, and weight loss. Design: We conducted searches of PubMed, Embase, and Google Scholar to August 2011. We included randomized controlled trials (RCTs) with interventions that lasted ≥6 mo that compared low-carbohydrate, vegetarian, vegan, low–glycemic index (GI), high-fiber, Mediterranean, and high-protein diets with control diets including low-fat, high-GI, American Diabetes Association, European Association for the Study of Diabetes, and low-protein diets. Results: A total of 20 RCTs were included (n = 3073 included in final analyses across 3460 randomly assigned individuals). The low-carbohydrate, low-GI, Mediterranean, and high-protein diets all led to a greater improvement in glycemic control [glycated hemoglobin reductions of −0.12% (P = 0.04), −0.14% (P = 0.008), −0.47% (P < 0.00001), and −0.28% (P < 0.00001), respectively] compared with their respective control diets, with the largest effect size seen in the Mediterranean diet. Low-carbohydrate and Mediterranean diets led to greater weight loss [−0.69 kg (P = 0.21) and −1.84 kg (P < 0.00001), respectively], with an increase in HDL seen in all diets except the high-protein diet. Conclusion: Low-carbohydrate, low-GI, Mediterranean, and high-protein diets are effective in improving various markers of cardiovascular risk in people with diabetes and should be considered in the overall strategy of diabetes management.

Effects of Low-Carbohydrate Diets Versus Low-Fat Diets on Metabolic Risk Factors: A Meta-Analysis of Randomized Controlled Clinical Trials

Article

Oct 2012

The effects of low-carbohydrate diets (≤45% of energy from carbohydrates) versus low-fat diets (≤30% of energy from fat) on metabolic risk factors were compared in a meta-analysis of randomized controlled trials. Twenty-three trials from multiple countries with a total of 2,788 participants met the predetermined eligibility criteria (from January 1, 1966 to June 20, 2011) and were included in the analyses. Data abstraction was conducted in duplicate by independent investigators. Both low-carbohydrate and low-fat diets lowered weight and improved metabolic risk factors. Compared with participants on low-fat diets, persons on low-carbohydrate diets experienced a slightly but statistically significantly lower reduction in total cholesterol (2.7 mg/dL; 95% confidence interval: 0.8, 4.6), and low density lipoprotein cholesterol (3.7 mg/dL; 95% confidence interval: 1.0, 6.4), but a greater increase in high density lipoprotein cholesterol (3.3 mg/dL; 95% confidence interval: 1.9, 4.7) and a greater decrease in triglycerides (-14.0 mg/dL; 95% confidence interval: -19.4, -8.7). Reductions in body weight, waist circumference and other metabolic risk factors were not significantly different between the 2 diets. These findings suggest that low-carbohydrate diets are at least as effective as low-fat diets at reducing weight and improving metabolic risk factors. Low-carbohydrate diets could be recommended to obese persons with abnormal metabolic risk factors for the purpose of weight loss. Studies demonstrating long-term effects of low-carbohydrate diets on cardiovascular events were warranted.

A Silent Response to the Obesity Epidemic Decline in US Physician Weight Counseling

Article

Oct 2012

Background: Guidelines recommend that physicians screen all adults for obesity and offer an intensive counseling and behavioral interventions for weight loss for obese adults. Current trends of weight-related counseling are unknown in the setting of the US obesity epidemic. Objectives: To describe primary care physician (PCP) weight-related counseling, comparing counseling rates in 1995-1996 and 2007-2008. Research design: Data analysis of outpatient PCP visits in 1995-1996 and 2007-2008, as reported in the National Ambulatory Medical Care Survey. Subjects: A total of 32,519 adult primary care visits with PCPs. Measures: Rates of counseling for weight, diet, exercise, and a composite variable, weight-related counseling (defined as counseling for weight, diet, or exercise) between survey years. Adjusted analyses controlled for patient and visit characteristics. Results: Weight counseling declined from 7.8% of visits in 1995-1996 to 6.2% of visits in 2007-2008 [adjusted odds ratios, 0.64; 95% confidence intervals, 0.53, 0.79]. Rates of receipt of diet, exercise, and weight-related counseling similarly declined. Greater declines in odds of weight-counseling receipt were observed among those with hypertension (47%), diabetes (59%), and obesity (41%), patients who stand the most to gain from losing weight. Conclusions: Rates of weight counseling in primary care have significantly declined despite increased rates of overweight and obesity in the United States. Further, these declines are even more marked in patients with obesity and weight-related comorbidities, despite expectations to provide such care by both patients and policymakers. These findings have implications for determining deliverable, novel ways to engage PCPs in addressing the obesity epidemic.

10-year follow-up of diabetes incidence and weight loss in the Diabetes Prevention Program Outcomes StudyDiabetes Prevention Program Research GroupThe Lancet200937497021677168610.1016/S0140-6736(09)61457-4

Article

Oct 2009
LANCET

In the 2.8 years of the Diabetes Prevention Program (DPP) randomised clinical trial, diabetes incidence in high-risk adults was reduced by 58% with intensive lifestyle intervention and by 31% with metformin, compared with placebo. We investigated the persistence of these effects in the long term. All active DPP participants were eligible for continued follow-up. 2766 of 3150 (88%) enrolled for a median additional follow-up of 5.7 years (IQR 5.5-5.8). 910 participants were from the lifestyle, 924 from the metformin, and 932 were from the original placebo groups. On the basis of the benefits from the intensive lifestyle intervention in the DPP, all three groups were offered group-implemented lifestyle intervention. Metformin treatment was continued in the original metformin group (850 mg twice daily as tolerated), with participants unmasked to assignment, and the original lifestyle intervention group was offered additional lifestyle support. The primary outcome was development of diabetes according to American Diabetes Association criteria. Analysis was by intention-to-treat. This study is registered with ClinicalTrials.gov, number NCT00038727. During the 10.0-year (IQR 9.0-10.5) follow-up since randomisation to DPP, the original lifestyle group lost, then partly regained weight. The modest weight loss with metformin was maintained. Diabetes incidence rates during the DPP were 4.8 cases per 100 person-years (95% CI 4.1-5.7) in the intensive lifestyle intervention group, 7.8 (6.8-8.8) in the metformin group, and 11.0 (9.8-12.3) in the placebo group. Diabetes incidence rates in this follow-up study were similar between treatment groups: 5.9 per 100 person-years (5.1-6.8) for lifestyle, 4.9 (4.2-5.7) for metformin, and 5.6 (4.8-6.5) for placebo. Diabetes incidence in the 10 years since DPP randomisation was reduced by 34% (24-42) in the lifestyle group and 18% (7-28) in the metformin group compared with placebo. During follow-up after DPP, incidences in the former placebo and metformin groups fell to equal those in the former lifestyle group, but the cumulative incidence of diabetes remained lowest in the lifestyle group. Prevention or delay of diabetes with lifestyle intervention or metformin can persist for at least 10 years. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

A Call for an End to the Diet Debates

Abstract

Recommended publications

Comments and Replies to Published Papers: Advancing Science or Unnecessary Quibbles?

Religious debate continues

Strontium90 in Human Diet

Gunfire echoes in debates on public understanding