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A low-carbohydrate, ketogenic diet to treat type 2 diabetes


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The low-carbohydrate, ketogenic diet (LCKD) may be effective for improving glycemia and reducing medications in patients with type 2 diabetes. From an outpatient clinic, we recruited 28 overweight participants with type 2 diabetes for a 16-week single-arm pilot diet intervention trial. We provided LCKD counseling, with an initial goal of <20 g carbohydrate/day, while reducing diabetes medication dosages at diet initiation. Participants returned every other week for measurements, counseling, and further medication adjustment. The primary outcome was hemoglobin A1c. Twenty-one of the 28 participants who were enrolled completed the study. Twenty participants were men; 13 were White, 8 were African-American. The mean [+/- SD] age was 56.0 +/- 7.9 years and BMI was 42.2 +/- 5.8 kg/m2. Hemoglobin A1c decreased by 16% from 7.5 +/- 1.4% to 6.3 +/- 1.0% (p < 0.001) from baseline to week 16. Diabetes medications were discontinued in 7 participants, reduced in 10 participants, and unchanged in 4 participants. The mean body weight decreased by 6.6% from 131.4 +/- 18.3 kg to 122.7 +/- 18.9 kg (p < 0.001). In linear regression analyses, weight change at 16 weeks did not predict change in hemoglobin A1c. Fasting serum triglyceride decreased 42% from 2.69 +/- 2.87 mmol/L to 1.57 +/- 1.38 mmol/L (p = 0.001) while other serum lipid measurements did not change significantly. The LCKD improved glycemic control in patients with type 2 diabetes such that diabetes medications were discontinued or reduced in most participants. Because the LCKD can be very effective at lowering blood glucose, patients on diabetes medication who use this diet should be under close medical supervision or capable of adjusting their medication.
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Nutrition & Metabolism
Open Access
A low-carbohydrate, ketogenic diet to treat type 2 diabetes
William S Yancy Jr*1,2, Marjorie Foy1, Allison M Chalecki1, Mary C Vernon3
and Eric C Westman2
Address: 1Center for Health Services Research in Primary Care, Department of Veterans' Affairs Medical Center (152), 508 Fulton Street, Durham,
NC, USA 27705, 2Department of Medicine, Duke University Medical Center, Durham, NC, USA and 3Private Bariatric and Family Practice, and
Clinical Faculty, University of Kansas School of Medicine, Lawrence, KS, USA
Email: William S Yancy* -; Marjorie Foy -; Allison M Chalecki -;
Mary C Vernon -; Eric C Westman -
* Corresponding author
Background: The low-carbohydrate, ketogenic diet (LCKD) may be effective for improving
glycemia and reducing medications in patients with type 2 diabetes.
Methods: From an outpatient clinic, we recruited 28 overweight participants with type 2 diabetes
for a 16-week single-arm pilot diet intervention trial. We provided LCKD counseling, with an initial
goal of <20 g carbohydrate/day, while reducing diabetes medication dosages at diet initiation.
Participants returned every other week for measurements, counseling, and further medication
adjustment. The primary outcome was hemoglobin A1c.
Results: Twenty-one of the 28 participants who were enrolled completed the study. Twenty
participants were men; 13 were White, 8 were African-American. The mean [± SD] age was 56.0
± 7.9 years and BMI was 42.2 ± 5.8 kg/m2. Hemoglobin A1c decreased by 16% from 7.5 ± 1.4% to
6.3 ± 1.0% (p < 0.001) from baseline to week 16. Diabetes medications were discontinued in 7
participants, reduced in 10 participants, and unchanged in 4 participants. The mean body weight
decreased by 6.6% from 131.4 ± 18.3 kg to 122.7 ± 18.9 kg (p < 0.001). In linear regression analyses,
weight change at 16 weeks did not predict change in hemoglobin A1c. Fasting serum triglyceride
decreased 42% from 2.69 ± 2.87 mmol/L to 1.57 ± 1.38 mmol/L (p = 0.001) while other serum lipid
measurements did not change significantly.
Conclusion: The LCKD improved glycemic control in patients with type 2 diabetes such that
diabetes medications were discontinued or reduced in most participants. Because the LCKD can
be very effective at lowering blood glucose, patients on diabetes medication who use this diet
should be under close medical supervision or capable of adjusting their medication.
Prior to the advent of exogenous insulin for the treatment
of diabetes mellitus in the 1920's, the mainstay of therapy
was dietary modification. Diet recommendations in that
era were aimed at controlling glycemia (actually, glycosu-
ria) and were dramatically different from current low-fat,
high-carbohydrate dietary recommendations for patients
with diabetes [1,2]. For example, the Dr. Elliot Joslin Dia-
betic Diet in 1923 consisted of "meats, poultry, game,
fish, clear soups, gelatin, eggs, butter, olive oil, coffee, tea"
Published: 01 December 2005
Nutrition & Metabolism 2005, 2:34 doi:10.1186/1743-7075-2-34
Received: 10 August 2005
Accepted: 01 December 2005
This article is available from:
© 2005 Yancy et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Nutrition & Metabolism 2005, 2:34
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and contained approximately 5% of energy from carbohy-
drates, 20% from protein, and 75% from fat [3]. A similar
diet was advocated by Dr. Frederick Allen of the same era
Recently, four studies have re-examined the effect of car-
bohydrate restriction on type 2 diabetes. One outpatient
study enrolled 54 participants with type 2 diabetes (out of
132 total participants) and found that hemoglobin A1c
improved to a greater degree over one year with a low-car-
bohydrate diet compared with a low-fat, calorie-restricted
diet [5,6]. Another study enrolled 8 men with type 2 dia-
betes in a 5-week crossover outpatient feeding study that
tested similar diets [7]. The participants had greater
improvement in glycohemoglobin while on the low-car-
bohydrate diet than when on a eucaloric low-fat diet. The
third study was an inpatient feeding study in 10 partici-
pants with type 2 diabetes [8]. After only 14 days, hemo-
globin A1c improved from 7.3% to 6.8%. In the fourth
study, 16 participants with type 2 diabetes who followed
a 20% carbohydrate diet had improvement of hemo-
globin A1c from 8.0% to 6.6% over 24 weeks [9]. Only
these latter three studies targeted glycemic control as a
goal, and two of these were intensely-monitored efficacy
studies in which all food was provided to participants for
the duration of the study [7,8]. Three of the studies [6,8,9]
mentioned that diabetic medications were adjusted but
only one of them provided detailed information regard-
ing these adjustments [9]. This information is critical for
patients on medication for diabetes who initiate a low-
carbohydrate diet because of the potential for adverse
effects resulting from hypoglycemia.
The purpose of this study was to evaluate the effects of a
low-carbohydrate, ketogenic diet (LCKD) in overweight
and obese patients with type 2 diabetes over 16 weeks.
Specifically, we wanted to learn the diet's effects on glyc-
emia and diabetes medication use in outpatients who pre-
pared (or bought) their own meals. In a previous article,
we reported the results observed in 7 individuals [10]; this
report includes data from those 7 individuals along with
data from additional participants enrolled subsequently.
Participants were recruited from the Durham Veterans
Affairs Medical Center (VAMC) outpatient clinics. Inclu-
sion criteria were age 35–75 years; body mass index (BMI)
>25 kg/m2; and fasting serum glucose >125 mg/dL or
hemoglobin A1c >6.5% without medications, or treatment
with oral hypoglycemic agents (OHA) and/or insulin.
Exclusion criteria were evidence of renal insufficiency,
liver disease, or unstable cardiovascular disease by history,
physical examination, and laboratory tests. All partici-
pants provided written informed consent approved by the
institutional review board. No monetary incentives were
At the first visit, participants were instructed how to fol-
low the LCKD as individuals or in small groups, with an
initial goal of 20 g carbohydrate per day. Participants
were taught the specific types and amounts of foods they
could eat, as well as foods to avoid. Initially, participants
were allowed unlimited amounts of meats, poultry, fish,
shellfish, and eggs; 2 cups of salad vegetables per day; 1
cup of low-carbohydrate vegetables per day; 4 ounces of
hard cheese; and limited amounts of cream, avocado,
olives, and lemon juice. Fats and oils were not restricted
except that intake of trans fats was to be minimized. Par-
ticipants were provided a 3-page handout and a hand-
book [11] detailing these recommendations. Participants
prepared or bought all of their own meals and snacks fol-
lowing these guidelines.
In addition, on the day the diet was initiated, diabetes
medications were reduced – generally, insulin doses were
halved, and sulfonylurea doses were halved or discontin-
ued. Due to the possible diuretic effects of the diet soon
after initiation, diuretic medications were discontinued if
of low dosage (up to 25 mg of hydrochlorothiazide or 20
mg of furosemide) or halved if of higher dosage. Partici-
pants were also instructed to take a standard multivitamin
and drink 6–8 glasses of water daily, and were encouraged
to exercise aerobically for 30 minutes at least three times
per week.
Participants returned every other week for 16 weeks for
further diet counseling and medication adjustment. When
a participant neared half the weight loss goal or experi-
enced cravings, he or she was advised to increase carbohy-
drate intake by approximately 5 g per day each week as
long as weight loss continued. Participants could choose
5 g carbohydrate portions from one of the following foods
each week: salad vegetables, low-carbohydrate vegetables,
hard or soft cheese, nuts, or low-carbohydrate snacks. Dia-
betes medication adjustment was based on twice daily
glucometer readings and hypoglycemic episodes, while
diuretic and other anti-hypertensive medication adjust-
ments were based on orthostatic symptoms, blood pres-
sure, and lower extremity edema.
Participants completed take-home food records (4 con-
secutive days, including a weekend) collected at baseline
and at weeks 2, 8, and 16 during the study. Participants
were given handouts with examples of how to complete
the records. A registered dietician analyzed the food
records using a nutrition software program (Food Proces-
sor SQL, ESHA Research, Inc., Salem, OR).
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The following measurements were made every other
week: anthropometric and vital sign measurements; urine
testing for ketones; and assessment for hypoglycemic epi-
sodes and other symptomatic side effects. Weight was
measured on a standardized digital scale while the partic-
ipant was wearing light clothes and shoes were removed.
Skinfold thickness was measured at 4 sites – the average of
2 measurements at each site was entered into an equation
to calculate percent body fat [12]. Waist circumference
was measured at the midpoint between the inferior rib
and the iliac crest using an inelastic tape; 2 measurements
were averaged in the analysis. Blood pressure and heart
rate were measured after the participant had been seated
quietly without talking for 3 minutes. Certified laboratory
technicians assessed urine ketones from a fresh specimen
using the following semi-quantitative scale: none, trace
(up to 0.9 mmol/L [5 mg/dL]), small (0.9–6.9 mmol/L
[5–40 mg/dL]), moderate (6.9–13.8 mmol/L [40–80 mg/
dL]), large80 (13.8–27.5 mmol/L [80–160 mg/dL]),
large160 (>27.5 mmol/L [160 mg/dL]). Hypoglycemic
episodes and symptomatic side effects were assessed by
direct questioning of the participant and by self-adminis-
tered questionnaires.
Blood specimens were obtained at weeks 0, 8, and 16 after
the participant had fasted overnight. The following serum
tests were performed in the hospital laboratory using
standardized methods: complete blood count, chemistry
panel, lipid panel, thyroid-stimulating hormone, and uric
acid. A non-fasting specimen was also drawn at weeks 4
and 12 to monitor electrolytes and kidney function.
The primary outcome was the change from baseline to
week 16 in hemoglobin A1c. Changes in all variables were
analyzed by the paired t-test or Wilcoxon signed-ranks
test, as appropriate. Linear regression analysis was used to
examine predictors of change in hemoglobin A1c. A p
value of 0.05 or less was considered statistically signifi-
cant. Statistical analysis was performed using SAS version
8.02 (SAS Institute, Cary, NC).
Of the 28 participants enrolled in the study, 21 completed
the 16 weeks of follow-up. Reasons for discontinuing the
study included unable to adhere to study meetings and
unable to adhere to the diet; no participant reported dis-
continuing as a result of adverse effects associated with the
intervention. All but one of the 21 participants were men;
62% (n = 13) were Caucasian, 38% (n = 8) were African-
American (Table 1). The mean age was 56.0 ± 7.9 years.
Adequate food records were available for analysis in a pro-
portion of participants at each of the 4 timepoints (Table
2). Participants completed food records at a mean of 2.5
and a median of 3 timepoints. In general, comparing
baseline to subsequent timepoints, mean carbohydrate
intake decreased substantially and energy intake
decreased moderately while protein and fat intake
remained fairly constant.
From baseline to week 16, the mean body weight
decreased significantly from 131.4 ± 18.3 kg to 122.7 ±
18.9 kg, BMI decreased from 42.2 ± 5.8 kg/m2 to 39.4 ±
6.0 kg/m2, and waist circumference from 130.0 ± 10.5 cm
to 123.3 ± 11.3 cm (Table 3). The percent change in body
weight was -6.6%. The mean percent body fat decreased
from 40.4 ± 5.8% to 37.0 ± 6.0%. Systolic and diastolic
blood pressures did not change significantly over the 16
weeks. The mean heart rate decreased from 81.2 ± 12.9
beats per minute to 74.6 ± 14.0 beats per minute (p =
Urine ketone data were missing in a median of 4 partici-
pants (range 0–8) at any given visit. The proportion of
participants with a urine ketone reading greater than trace
was 1 of 17 participants at baseline, 5 of 17 participants at
week 2, and similar frequencies at subsequent visits until
week 14 when 2 of 18 participants had readings greater
than trace and week 16 when 2 of 21 participants had
Table 1: Baseline characteristics (n = 21)
Characteristic Summary
Age, years, mean (SD) 56.0 (7.9)
Gender, male, n (%) 20 (95%)
Race, White, n (%) 13 (62%)
African-American, n (%) 8 (38%)
Weight, kg, mean (SD) 131.4 (18.3)
BMI, kg/m2, mean (SD) 42.2 (5.8)
Table 2: Diet composition
Nutrient Week 0
Mean (SD)
Week 2
Mean (SD)
Week 8
Mean (SD)
Week 16
Mean (SD)
n 141515 8
Carbohydrate, g 204.4 (118.4) 44.6 (27.4) 44.0 (29.1) 33.8 (24.6)
Protein, g 95.8 (23.9) 111.7 (38.6) 114.8 (57.0) 98.5 (52.5)
Fat, g 95.5 (27.3) 95.1 (47.2) 106.6 (47.6) 93.5 (63.7)
Energy, kcal 2031.5 (521.4) 1515.5 (587.2) 1603.4 (713.0) 1418.7 (756.9)
Nutrition & Metabolism 2005, 2:34
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readings greater than trace. During the study, only 27 of
151 urine ketone measurements were greater than trace,
with one participant accounting for all 7 occurrences of
the highest urine ketone reading (large160).
In regard to serum measurements, the mean fasting glu-
cose decreased by 17% from 9.08 ± 4.09 mmol/L at base-
line to 7.57 ± 2.63 mmol/L at week 16 (p = 0.04) (Table
4). Serum sodium and chloride levels increased signifi-
cantly, but only by 1% and 3%, respectively. Uric acid
level decreased by 10% (p = 0.01). Serum triglyceride
decreased 42% from 2.69 ± 2.87 mmol/L to 1.57 ± 1.38
mmol/L (p = 0.001). Increases occurred in both high-den-
sity lipoprotein (HDL) cholesterol (8%) and low-density
lipoprotein (LDL) cholesterol (10%) but these changes
were of borderline statistical significance (p = 0.08 and p
= 0.1, respectively). The following blood tests did not
change significantly: total cholesterol, potassium, bicar-
bonate, urea nitrogen, creatinine, calcium, thyroid-stimu-
lating hormone, and hemoglobin.
The primary outcome, hemoglobin A1c, decreased from
7.5 ± 1.4% at baseline to 6.3 ± 1.0% at week 16 (p <
0.001), a 1.2% absolute decrease and a 16% relative
decrease (Table 4). All but two participants (n = 19 or
90%) had a decrease in hemoglobin A1c (Figure 1). The
absolute decrease in hemoglobin A1c was at least 1.0% in
11 (52%) participants. The relative decrease in hemo-
globin A1c from baseline was greater than 10% in 14
(67%) participants, and greater than 20% in 6 (29%) par-
ticipants. In regression analyses, the change in hemo-
globin A1c was not predicted by the change in body
weight, waist circumference, or percent body fat at 16
weeks (all p > 0.05).
Table 3: Anthropometric and vital sign measurements (n = 21)
Measurement Week 0
Mean (SD)
Week 16
Mean (SD)
p value*
Body weight, kg 131.4 (18.3) 122.7 (18.9) -6.6 <0.001
Body mass index, kg/m242.2 (5.8) 39.4 (6.0) -6.6 <0.001
Waist circumference, cm 130.0 (10.5) 123.3 (11.3) -5.2 <0.001
Percent body fat, % 40.4 (5.8) 37.0 (6.0) -8.4 <0.001
Systolic blood pressure, mm Hg 135.1 (14.8) 135.4 (17.6) 0.2 0.9
Diastolic blood pressure, mm Hg 79.2 (14.9) 74.1 (13.0) -6.4 0.1
Heart rate, beats/min 81.2 (12.9) 74.6 (14.0) -8.1 0.01
*By paired t-test or Wilcoxon signed-ranks test.
Table 4: Serum test results (n = 21)
Measurement Week 0
Mean (SD)
Week 16
Mean (SD)
p value*
Hemoglobin A1c, % 7.5 (1.4) 6.3 (1.0) -16.0 <0.001
Glucose, mmol/L 9.08 (4.09) 7.57 (2.63) -16.6 0.04
Total cholesterol, mmol/L 4.61 (1.40) 4.54 (1.26) -1.5 0.7
Triglyceride, mmol/L 2.69 (2.87) 1.57 (1.38) -41.6 0.001
HDL-C, mmol/L 0.92 (0.20) 0.99 (0.22) 7.6 0.08
LDL-C, mmol/L 2.51 (0.64) 2.77 (0.89) 10.4 0.1
Sodium, mmol/L 138.2 (3.4) 140.2 (3.4) 1.4 0.02
Potassium, mmol/L 4.2 (0.4) 4.2 (0.3) 0 0.2
Chloride, mmol/L 101.0 (3.4) 103.8 (2.8) 2.8 0.001
Bicarbonate, mmol/L 28.8 (2.0) 28.2 (2.5) -2.1 0.3
Urea nitrogen, mg/dL 5.90 (1.90) 6.27 (1.81) 6.3 0.3
Creatinine, µmol/L 82.8 (20.4) 79.9 (19.1) -3.5 0.3
Calcium, mmol/L 2.32 (0.11) 2.33 (0.08) 0.4 0.8
Uric acid, µmol/L 403.5 (94.6) 352.1 (85.4) -10.3 0.01
TSH, mIU/L 1.6 (1.0) 1.4 (0.7) -12.7 0.2
Hemoglobin, g/L 142 (11) 141 (10) -0.7 0.8
Legend: TSH = thyroid-stimulating hormone, HDL-C = high-density lipoprotein cholesterol, LDL-C = low-density lipoprotein cholesterol.
* By paired t-test or Wilcoxon signed-ranks test.
Serum calcium, TSH, total cholesterol, triglyceride, and HDL-C results are based on n of 20 because one participant did not have these tests at
baseline. Uric acid is based on n of 19. LDL-C is based on n of 17 because triglyceride levels were too high at baseline to calculate LDL-C in 3
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The improvement in glycemic control occurred while
medications for diabetes were discontinued or reduced in
most participants (Table 5). During the study, hyperten-
sion and hyperlipidemia medication doses were not
increased from baseline nor were new agents added,
except in 3 individuals. No serious adverse effects related
to the diet occurred. One participant had a hypoglycemic
episode requiring assistance from emergency services after
he skipped a meal but the episode was aborted without
need for transportation to the emergency room or hospi-
In this single-arm, 4-month diet intervention, an LCKD
resulted in significant improvement of glycemia, as meas-
ured by fasting glucose and hemoglobin A1c, in patients
with type 2 diabetes. More importantly, this improvement
was observed while diabetes medications were reduced or
discontinued in 17 of the 21 participants, and were not
changed in the remaining 4 participants. Participants also
experienced reductions in body weight, waist circumfer-
ence, and percent body fat but these improvements were
moderate and did not predict the change in hemoglobin
A1c in regression analyses.
Several recent studies indicate that a low-carbohydrate
diet is effective at improving glycemia. A few studies have
shown that in non-diabetic individuals, low-carbohydrate
diets were more effective than higher carbohydrate diets at
improving fasting serum glucose [13,14] and insulin
[6,14-16], and at improving insulin sensitivity as meas-
ured by the homeostasis model [6]. One of these studies
also included diabetic patients and noted a comparative
improvement in hemoglobin A1c after 6 months (low fat
diet: 0.0 ± 1.0%; low carbohydrate diet: -0.6 ± 1.2%, p =
0.06) [6] and 12 months (low fat diet: -0.1 ± 1.6%; low
carbohydrate diet: -0.7 ± 1.0%, p = 0.019) duration [5]. In
a 5-week crossover feeding study, 8 men with type 2 dia-
betes had greater improvement in fasting glucose, 24-hour
glucose area-under-the-curve (AUC), 24-hour insulin
AUC, and glycohemoglobin while on the low-carbohy-
drate diet than when on a eucaloric low-fat diet [7]. In a
14-day inpatient feeding study, 10 participants with type
2 diabetes experienced improvements in hemoglobin A1c
and insulin sensitivity as measured by the euglycemic
hyperinsulinemic clamp method [8]. Hemoglobin A1c
also improved in an outpatient study of 16 participants
who followed a 20% carbohydrate diet for 24 weeks [9].
Similar to our results, three studies noted that diabetes
medications were reduced in some participants[6,8,9],
although details were provided in only one study. We also
discontinued diuretic medications during diet initiation
because of concern for additional diuresis incurred by the
diet. This concern was based on the theoretical effects of
the diet [17], observed effects of the diet on body water by
bioelectric impedance [18], and practical experience with
the diet [19]. Until we learn more about using low carbo-
hydrate diets, medical monitoring for hypoglycemia,
dehydration, and electrolyte abnormalities is imperative
in patients taking diabetes or diuretic medications.
While body weight decreased significantly (-8.5 kg) in
these 21 diabetic participants, the mean weight loss was
less compared with what we observed in the LCKD partic-
ipants of an earlier trial (-12.0 kg) [18]. Given that the dia-
betic participants had a higher baseline mean weight than
the LCKD participants of our previous trial (131 kg vs. 97
kg), this translates into an even more dramatic disparity in
percent change in body weight (-6.6% vs. -12.9%). This
lesser weight loss might result from several factors. First,
in the current study, most of the participants were taking
insulin and/or oral hypoglycemic agents that are known
to induce weight gain[20,21] Second, these same agents,
particularly insulin, inhibit ketosis, which is strived for in
the earliest phases of the LCKD; while it remains unclear
whether ketones actually play a role in weight loss on the
LCKD, previous research in non-diabetic patients has
shown a positive correlation between level of ketonuria
and weight loss success [22]. Lastly, compared with our
previous study the participants in the current study had
more comorbid illness, lower socioeconomic status, and a
shorter duration of follow-up (16 weeks versus 24 weeks),
all of which are associated with reduced success on any
weight loss program [23].
The main limitations of our study are its small sample
size, short duration, and lack of control group. That the
main outcome, hemoglobin A1c, improved significantly
despite the small sample size and short duration of fol-
low-up speaks to the dramatic and consistent effect of the
LCKD on glycemia. For other effects, however, such as the
Hemoglobin A1c for each participantFigure 1
Hemoglobin A1c for each participant. *Red line is the
group mean. P value is for the mean change from baseline.
Week 0
Week 16
Hemoglobin A1c, %
Mean= 7.4%
Mean= 6.3%,
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rises in serum LDL and HDL cholesterol, the small sample
size might be the reason statistical significance was not
reached. Future studies of larger samples and containing a
control group are needed to better address questions
about the effect of the LCKD on serum lipids in patients
with type 2 diabetes.
In summary, the LCKD had positive effects on body
weight, waist measurement, serum triglycerides, and glyc-
emic control in a cohort of 21 participants with type 2 dia-
betes. Most impressive is that improvement in
hemoglobin A1c was observed despite a small sample size
and short duration of follow-up, and this improvement in
glycemic control occurred while diabetes medications
were reduced substantially in many participants. Future
research must further examine the optimal medication
adjustments, particularly for diabetes and diuretic agents,
in order to avoid possible complications of hypoglycemia
and dehydration. Because the LCKD can be very effective
at lowering blood glucose, patients on diabetes medica-
tion who use this diet should be under close medical
supervision or capable of adjusting their medication.
Competing interests
Dr. Vernon has held a consulting relationship with Atkins
Nutritionals, Inc.
Table 5: Diabetes medication changes
Participant Week 0
Total daily dose
Week 16
Total daily dose
Participants with diabetes medications discontinued (n = 7 of 21)
5 glipizide 10 mg
metformin 1000 mg
6 glipizide 20 mg
metformin 1500 mg
7 metformin 2000 mg
rosiglitazone 8 mg
9 metformin 1000 mg none
15 metformin 1000 mg none
22 metformin 1000 mg none
24 metformin 1000 mg none
Participants with diabetes medications reduced (n = 10 of 21)
3 70/30 insulin 50 units
metformin 1000 mg
metformin 1000 mg
11 metformin 2000 mg
glyburide 20 mg
metformin 2000 mg
16 metformin 2000 mg
pioglitazone 45 mg
glipizide 20 mg
metformin 2000 mg
21 metformin 1500 mg
pioglitazone 30 mg
metformin 1000 mg
8 NPH 145 units
metformin 1000 mg
NPH 25 units
metformin 1000 mg
13 70/30 insulin 70 units
metformin 2550 mg
70/30 insulin 35 units
metformin 2550 mg
23 70/30 insulin 110 units
pioglitazone 45 mg
70/30 insulin 80 units
pioglitazone 45 mg
metformin 1000 mg
25 NPH 70 units, R 30 units
metformin 2000 mg
pioglitazone 45 mg
NPH 8 units
metformin 2000 mg
pioglitazone 45 mg
27 70/30 insulin 86 units
metformin 2000 mg
70/30 insulin 18 units
metformin 2000 mg
28 NPH insulin 110 units
lispro insulin 90 units
glipizide 20 mg
NPH insulin 30 units
glipizide 20 mg
Participants with diabetes medications unchanged (n = 4 of 21)
1 none none
2 metformin 1700 mg metformin 1700 mg
10 none none
26 metformin 2000 mg metformin 2000 mg
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Authors' contributions
WY conceived, designed, and coordinated the study; par-
ticipated in data collection; performed statistical analysis;
and drafted the manuscript. MF assisted with study
design, performed data collection, and helped to draft the
manuscript. AC analyzed the food records. MV assisted
with study/intervention design and safety monitoring. EW
participated in the conception and design of the study,
and assisted with the statistical analysis. All authors read
and approved the final manuscript.
Dr. Yancy is s uppor ted by a VA He alth Services R esear ch Career Devel op-
ment Award (RCD 02-183-1).
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... The mean fasting glucose decreased by 16.6% from 9.08 ± 4.09 mmol/L at baseline to 7.57 ± 2.63 mmol/L at week 16 (p = 0.04). 18 The hemoglobin A1c decreased from 7.5 ± 1.4% at baseline to 6.3 ± 1.0% at week 16 (p < 0.001). 18 These results were encouraging, but with short duration and small sample size. ...
... 18 The hemoglobin A1c decreased from 7.5 ± 1.4% at baseline to 6.3 ± 1.0% at week 16 (p < 0.001). 18 These results were encouraging, but with short duration and small sample size. ...
The ketogenic diet has become increasing popular in recent years. With 25.4 million unique searches, the keto diet was the most Googled diet in the United States in 2020.1 With increased consumer interest, the "keto" food industry has grown rapidly, and as a result, the global ketogenic diet market was valued at $9.57 billion in 2019.2 The ketogenic diet has been discussed in popular culture by celebrities, health magazines, and documentaries. The popularity of this diet, and diets in general may be explained by the obesity epidemic in the United States and Missouri.
... The KD as a high fat, moderate protein, very low carbohydrate diet has clinically been used in multiple metabolic and neurological disorders such as diabetes, obesity and epilepsy (8)(9)(10)(11)(12). Previous studies have indicated that a KD is effective in reducing both glucose and insulin levels (13)(14)(15). ...
In this systematic review and meta-analysis of clinical controlled trials (CCTs) we aimed to investigate the efficacy of KDs as an adjuvant therapy on cardiometabolic outcomes in patient with cancer compared to conventional non-ketogenic diets. Only CCTs involving cancer patients that were assigned to either a KD or a standard diet control group were selected. Two reviewers independently extracted the data, and a meta-analysis was performed using a random effects model to estimate weighted mean differences (WMDs) and confidence intervals (CIs) in body composition, metabolite, lipid profile, liver and kidney function parameters and quality of life. This meta-analysis showed a significant reduction in body weight (WMD= −2.99 kg; 95% CI: −4.67, −1.31; and P < 0.001), BMI (WMD= −1.08 kg/m 2 ; 95% CI: −1.81, −0.34; P ≤ 0.002) and fat mass (WMD= −1.48 kg; 95% CI: −2.56, −0.40; and P = 0.007) by a KD. KDs significantly decreased glucose (WMD= −5.22 mg/dl; 95% CI: −9.0, −1.44; and P = 0.007), IGF-1 (WMD= −17.52 ng/ml; 95% CI: −20.24, −14.8; and P ˂0.001) and triglyceride (WMD= −24.46 mg/dl; 95% CI: −43.96, −4.95; and P = 0.014) levels. Furthermore, KDs induced ketosis by increasing β-hydroxybutyrate (WMD= 0.56 mmol/l; 95% CI: 0.37, 0.75; and P < 0.001). There were non-significant pooled effects of KDs on improving insulin, C-reactive protein and cholesterol levels and kidney and liver function. Emotional functioning was even increased significantly in the KD compared to the SD groups. In summary we found that KDs result in a greater reduction in glucose, IGF-1, triglycerides, body weight, BMI, and fat mass in cancer patients compared to traditional non-ketogenic diets and improved emotional functioning. The quality of evidence in the meta-analysis was moderate according to the Nutrigrade assessment.
... The effect of KD on metabolic parameters is variable depending on the composition of protein, fat, and carbohydrates as well as on the duration of its use. Some reports suggested that KD was shown to reduce fasting blood glucose and HbA1c levels in patients with diabetes [65][66][67][68], in normal subjects [69] and in rodents [70]. Interestingly, KD was also shown to reduce glucose metabolism in rodents and humans [71][72][73]. ...
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Background Breast cancer chemotherapy with high dose alkylating agents is severely limited by their collateral toxicity to crucial normal tissues such as immune and gut cells. Taking advantage of the selective dependence of cancer cells on high glucose and combining glucose deprivation with these agents could produce therapeutic synergy. Methods In this study we examined the effect of glucose as well as its deprivation, and antagonism using the non-metabolized analogue 2-deoxy glucose, on the proliferation of several breast cancer cell lines MCF7, MDA-MB-231, YS1.2 and pII and one normal breast cell line, using the MTT assay. Motility was quantitatively assessed using the wound healing assay. Lactate, as the end product of anaerobic glucose metabolism, secreted into culture medium was measured by a biochemical assay. The effect of paclitaxel and doxorubicin on cell proliferation was tested in the absence and presence of low concentrations of glucose using MTT assay. Results In all cell lines, glucose supplementation enhanced while glucose deprivation reduced both their proliferation and motility. Lactate added to the medium could substitute for glucose. The inhibitory effects of paclitaxel and doxorubicin were significantly enhanced when glucose concentration was decreased in the culture medium, requiring 1000-fold lesser concentration to achieve a similar degree of inhibition to that seen in glucose-containing medium. Conclusion Our data show that a synergy was obtained by combining paclitaxel and doxorubicin with glucose reduction to inhibit cancer cell growth, which in vivo , might be achieved by applying a carbohydrate-restricted diet during the limited phase of application of chemotherapy; this could permit a dose reduction of the cytotoxic agents, resulting in greater tolerance and lesser side effects.
... Moreover, the carbohydrate content decreased from 74.93% in control bread to 50.5% and 44.34% with the substitution of banana peel at 5% and 10%, respectively. Some studies provided evidence that carbohydrate restriction improved blood glucose control, insulin resistance and obesity (Yancy et al., 2005). Low-carbohydrate bread may be beneficial for some diabetic patients in optimising their blood glucose regulation or for patients who prefer to eat fewer carbohydrates. ...
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Background The use of agricultural by-products as a source of functional ingredients, particularly those from crop plants, has received great interest. Banana (Musa spp.) is a common food crop worldwide, but its peel, similar to other agricultural by-products, is often discarded. Banana peel has the potential to be transformed into functional foods because it is historically consumed as food and medicine in some regions of the world. Scope and approach: Current analysis recaps the nutritional characteristics, bioactive elements and potential health-promoting properties of banana peel and its utilisation in the food industry. Key Findings and Conclusion: The discoveries, particularly on the broad array of bioactive chemical constituents in peel and their related biological activities, seem to rationalise the proposed use of banana peel in several food industries. Banana peel is appreciated for its bioactive components, particularly the phenolic compounds. The major phenolic compounds found in the banana peel are grouped as flavonols, hydroxycinnamic acids, flavan-3-ols, and catecholamines. The incorporation of banana peel into food products enhanced the nutritional content, particularly the dietary fibre and phenolic content. It has been demonstrated that banana peel reduces lipid oxidation, particularly in meat-based products. Despite the nutrients offered by banana peels, this paper discusses the potential anti-nutrient content that must be addressed. From this review, banana peel shows great potential to be developed into beneficial functional foods and nutraceuticals. However, proper regulation and legalisation of bioactive enrichment of food products from the banana peel are required to ensure its safety for human consumption.
Ketogenic diets reduce food intake, increase energy expenditure and cause weight loss in rodents Prior preclinical studies have been completed at room temperature, a condition which induces thermal stress and limits clinical translatability We demonstrate that ketogenic diet‐induced reductions in food intake, increases in energy expenditure, weight loss and improvements in glucose homeostasis are similar in mice housed at room temperature or thermal neutrality Ketogenic diet induced reductions in food intake appear to explain a large degree of weight loss. Similarly, switching mice from a ketogenic to an obesogenic diet leads to hyperphagia mediated weight gain Ketogenic diets (KDs) are a popular tool used for weight management. Studies in mice have demonstrated that KDs reduce food intake, increase energy expenditure and cause weight loss. These studies were completed at room temperature (RT), a condition below the animal's thermal neutral (TN) zone which induces thermal stress. As energy intake and expenditure are sensitive to environmental temperature it's not clear if a KD would exert the same beneficial effects under TN conditions. Adherence to restrictive diets is poor and consequently it is important to examine the effects, and underlying mechanisms, of cycling from a ketogenic to an obesogenic diet. The purpose of the current study was to determine if housing temperature impacted the effects of a KD in obese mice and to determine if the mechanisms driving KD‐induced weight loss reverse when mice are switched to an obesogenic high fat diet. We demonstrate that KD‐induced reductions in food intake, increases in energy expenditure, weight loss and improvements in glucose homeostasis are not dependent upon housing temperature. KD‐induced weight loss, seems to be largely explained by reductions in caloric intake while cycling mice back to an obesogenic diet following a period of KD feeding leads to hyperphagia‐induced weight gain. Collectively, our results suggest that prior findings with mice fed a KD at RT are likely not an artifact of how mice were housed and that initial changes in weight when transitioning from an obesogenic to a ketogenic diet or back, are largely dependent on food intake. Abstract figure legend The impact of housing temperature on ketogenic diet mediated changes in energy expenditure, food intake and weight gain. This article is protected by copyright. All rights reserved
Purpose of review: This review provides a rationale for implementing carbohydrate restriction as a dietary therapy to improve biomarkers of cardiovascular health and suggests that this will require a paradigm shift away from what is currently promulgated as a 'heart-healthy' diet. Recent findings: Type 2 diabetes mellitus (T2DM), metabolic syndrome, and related co-morbidities are major risk factors for cardiovascular disease (CVD). Ideally, then, a diet intended to support cardiovascular health should be one that improves or reverses these underlying risk factors. Carbohydrate restriction is effective for this purpose as well as for favorably impacting atherogenic dyslipidemia. Recent consensus reports from select national organizations have endorsed low-carbohydrate diets for improving glycemia and cardiovascular risk. Reluctance among public health organizations and some clinicians to more widely promote this therapeutic nutritional approach is driven primarily by the increase in serum low-density lipoprotein cholesterol (LDL-C) observed in a proportion of individuals who adopt a low-carbohydrate diet. Here we explore the rationale for using carbohydrate restriction to improve cardiovascular health by way of favorably impacting T2DM and insulin resistance, and why this salutary effect outweighs the potential adverse effects of an increase in serum LDL-C. Summary: Carbohydrate restriction is a logical foundation for a dietary intervention intended to reduce CVD risk, particularly among individuals with T2DM or metabolic syndrome.
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Over the past 50 years, many countries around the world have faced an unchecked pandemic of obesity and type 2 diabetes (T2DM). As best practice treatment of T2DM has done very little to check its growth, the pandemic of diabesity now threatens to make health-care systems economically more difficult for governments and individuals to manage within their budgets. The conventional view has been that T2DM is irreversible and progressive. However, in 2016, the World Health Organization (WHO) global report on diabetes added for the first time a section on diabetes reversal and acknowledged that it could be achieved through a number of therapeutic approaches. Many studies indicate that diabetes reversal, and possibly even long-term remission, is achievable, belying the conventional view. However, T2DM reversal is not yet a standardized area of practice and some questions remain about long-term outcomes. Diabetes reversal through diet is not articulated or discussed as a first-line target (or even goal) of treatment by any internationally recognized guidelines, which are mostly silent on the topic beyond encouraging lifestyle interventions in general. This review paper examines all the sustainable, practical, and scalable approaches to T2DM reversal, highlighting the evidence base, and serves as an interim update for practitioners looking to fill the practical knowledge gap on this topic in conventional diabetes guidelines.
Starch is an important dietary carbohydrate in the human diet and is greatly associated with human health. The health effects of starch are classically evaluated by postprandial glycemic response. However, glycemic response is the test result of blood glucose level and sometimes fails to perfectly describe the health effects exerted by starch. Therefore, other factors, besides glycemic response, merit consideration. Herein, we endeavor to provide some insights into the description of health effects exerted by starch. For this purpose, we summarize advances in recent studies to support the crucial roles of glucose kinetics, insulin response, and gut hormones release. A moderate postprandial insulin response and an enhanced release of several specific gut hormones are critical characteristics of a healthier starch, such as those slowly digested till the distal ileum. It is also hoped that further studies can develop feasible methods to produce tailor-made starches with individualized health effects.
Dietary restriction of carbohydrate has been demonstrated to be beneficial for nervous system dysfunction in animal models and may be beneficial for human chronic pain. The purpose of this review is to assess the impact of a low-carbohydrate/ketogenic diet on the adult nervous system function and inflammatory biomarkers to inform nutritional research for chronic pain. An electronic data base search was carried out in May 2021. Publications were screened for prospective research with dietary carbohydrate intake <130g/day and duration of ≥2 weeks. Studies were categorised into those reporting adult neurological outcomes to be extracted for analysis and those reporting other adult research outcomes Both groups were screened again for reported inflammatory biomarkers. From 1548 studies there were 847 studies included. Sixty-four reported neurological outcomes with 83% showing improvement. Five hundred and twenty-three studies had a different research focus (metabolic n=394, sport/performance n=51, cancer n=33, general n=30, neurological with non-neuro outcomes n=12, or gastrointestinal n=4). The second screen identified 63 studies reporting on inflammatory biomarkers with 71% reporting a reduction in inflammation. The overall results suggest a favourable outcome on the nervous system and inflammatory biomarkers from a reduction in dietary carbohydrates. Both nervous system sensitisation and inflammation occur in chronic pain and the results from this review indicate it may be improved by low-carbohydrate nutritional therapy. More clinical trials within this population are required to build on the few human trials that have been done.
Purpose To gain a better and more comprehensive understanding, this study aims to investigate the literature to explore the two popular diets’ health benefits and concerns. Google Scholar and PubMed were used to search for available and relevant nutrition and health articles that pertain to the benefits and concerns of plantogenic and ketogenic diets. Search terms like low carbohydrate, diet, ketogenic, vegetarian and chronic diseases were used. Information was obtained from review articles and original research articles and checked for accuracy. Ketogenic diets have been used for a long time for convulsion in children and now reappeared for weight loss purposes. Design/methodology/approach Ketogenic and plantogenic (plant-based) diets have been adopted today by many professionals and the public. Findings Ketogenic diets have been used for a long time for convulsion in children and now reappeared for weight loss purposes. Plantogenic diets also have been practiced for many years for religious, health and environmental reasons. Compared to plantogenic diets, ketogenic diets lack long-term evidence of its potential benefits and harm. Research limitations/implications Maybe Lacto-ovo vegetarian and pesco-vegetarian (eat fish but not meats) diets are OK. However, for strict plantogenic diets (total plantogenic/vegan diet), the risk of mineral or vitamin deficiency is present (Melina et al. , 2016). Of particular concern is dietary vitamin B12, which is obtained mostly from animal sources (Melina et al. , 2016). A long-term deficiency of vitamin B12 can lead to macrocytic anemia and cause neuro and psychological effects (Obeid et al. , 2019). Also, omega-3 fatty acids may be deficient in such a diet and probably need to be supplemented on those who follow the total plantogenic diet (Melina et al. , 2016). Other deficiencies of concern would be zinc, iron, calcium, vitamin D and iodine (Melina et al. , 2016). Another disadvantage is that many junk foods could be easily classified within the plantogenic diet, such as sugar, cakes, French fries, white bread and rice, sugar-sweetened beverages and sweets in general. These items are related to higher weight gain and, consequently, to a higher incidence of diabetes and other chronic diseases (Schulze et al. , 2004; Malik et al. , 2006; Fung et al. , 2009). Originality/value Plantogenic diets were concluded to have sustainable health benefits for humans and the environment over ketogenic diets, which could be used but under professional follow-up only.
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Background Improved blood-glucose control decreases the progression of diabetic microvascular disease, but the effect on macrovascular complications is unknown. There is concern that sulphonylureas may increase cardiovascular mortality in patients with type 2 diabetes and that high insulin concentrations may enhance atheroma formation. We compared the effects of intensive blood-glucose control with either sulphonylurea or insulin and conventional treatment on the risk of microvascular and macrovascular complications in patients with type 2 diabetes in a randomised controlled trial. Methods 3867 newly diagnosed patients with type 2 diabetes, median age 54 years (IQR 48-60 years), who after 3 months' diet treatment had a mean of two fasting plasma glucose (FPG) concentrations of 6.1-15.0 mmol/L were randomly assigned intensive policy with a sulphonylurea (chlorpropamide, glibenclamide, or. glipizide) or with insulin, or conventional policy with diet. The aim in the intensive group was FPG less than 6 mmol/L. in the conventional group, the aim was the best achievable FPG with diet atone; drugs were added only if there were hyperglycaemic symptoms or FPG greater than 15 mmol/L. Three aggregate endpoints were used to assess differences between conventional and intensive treatment: any diabetes-related endpoint (sudden death, death from hyperglycaemia or hypoglycaemia, fatal or non-fatal myocardial infarction, angina, heart failure, stroke, renal failure, amputation [of at least one digit], vitreous haemorrhage, retinopathy requiring photocoagulation, blindness in one eye,or cataract extraction); diabetes-related death (death from myocardial infarction, stroke, peripheral vascular disease, renal disease, hyperglycaemia or hypoglycaemia, and sudden death); all-cause mortality. Single clinical endpoints and surrogate subclinical endpoints were also assessed. All analyses were by intention to treat and frequency of hypoglycaemia was also analysed by actual therapy. Findings Over 10 years, haemoglobin A(1c) (HbA(1c)) was 7.0% (6.2-8.2) in the intensive group compared with 7.9% (6.9-8.8) in the conventional group-an 11% reduction. There was no difference in HbA(1c) among agents in the intensive group. Compared with the conventional group, the risk in the intensive group was 12% lower (95% CI 1-21, p=0.029) for any diabetes-related endpoint; 10% lower (-11 to 27, p=0.34) for any diabetes-related death; and 6% lower (-10 to 20, p=0.44) for all-cause mortality. Most of the risk reduction in the any diabetes-related aggregate endpoint was due to a 25% risk reduction (7-40, p=0.0099) in microvascular endpoints, including the need for retinal photocoagulation. There was no difference for any of the three aggregate endpoints the three intensive agents (chlorpropamide, glibenclamide, or insulin). Patients in the intensive group had more hypoglycaemic episodes than those in the conventional group on both types of analysis (both p<0.0001). The rates of major hypoglycaemic episodes per year were 0.7% with conventional treatment, 1.0% with chlorpropamide, 1.4% with glibenclamide, and 1.8% with insulin. Weight gain was significantly higher in the intensive group (mean 2.9 kg) than in the conventional group (p<0.001), and patients assigned insulin had a greater gain in weight (4.0 kg) than those assigned chlorpropamide (2.6 kg) or glibenclamide (1.7 kg). Interpretation Intensive blood-glucose control by either sulphonylureas or insulin substantially decreases the risk of microvascular complications, but not macrovascular disease, in patients with type 2 diabetes. None of the individual drugs had an adverse effect on cardiovascular outcomes. All intensive treatment increased the risk of hypoglycaemia.
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Context.— Intensive treatment of type 1 diabetes results in greater weight gain than conventional treatment.Objective.— To determine the effect of this weight gain on lipid levels and blood pressure.Design.— Randomized controlled trial; ancillary study of the Diabetes Control and Complications Trial (DCCT).Setting.— Twenty-one clinical centers.Participants.— The 1168 subjects enrolled in DCCT with type 1 diabetes who were aged 18 years or older at baseline.Intervention.— Randomized to receive either intensive (n=586) or conventional (n=582) diabetes treatment with a mean follow-up of 6.1 years.Main Outcome Measures.— Plasma lipid levels and blood pressure in each treatment group categorized by quartile of weight gain.Results. —With intensive treatment, subjects in the fourth quartile of weight gain had the highest body mass index (BMI) (a measure of weight adjusted for height), blood pressure, and levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol (LDL-C), and apolipoprotein B compared with the other weight gain quartiles with the greatest difference seen when compared with the first quartile (mean values for the highest and lowest quartiles: BMI, 31 vs 24 kg/m2; blood pressure, 120/77 mm Hg vs 113/73 mm Hg; triglyceride, 0.99 mmol/L vs 0.79 mmol/L [88 mg/dL vs 70 mg/dL]; LDL-C, 3.15 mmol/L vs 2.74 mmol/L [122 mg/dL vs 106 mg/dL]; and apolipoprotein B, 0.89 g/L vs 0.78 g/L; all P<.001). In addition, the fourth quartile group had a higher waist-to-hip ratio; more cholesterol in the very low density lipoprotein, intermediate dense lipoprotein, and dense LDL fractions; and lower high-density lipoprotein cholesterol and apolipoprotein A-I levels compared with the first quartile. Baseline characteristics were not different between the first and fourth quartiles of weight gain with intensive therapy except for a higher hemoglobin A1c in the fourth quartile. Weight gain with conventional therapy resulted in smaller increases in BMI, lipids, and systolic blood pressure.Conclusions.— The changes in lipid levels and blood pressure that occur with excessive weight gain with intensive therapy are similar to those seen in the insulin resistance syndrome and may increase the risk of coronary artery disease in this subset of subjects with time. Figures in this Article PATIENTS WITH type 1 diabetes characteristically gain weight with the institution of insulin therapy but may remain leaner than nondiabetic control subjects.1- 2 With intensification of diabetes therapy, continued weight gain correlates inversely with improvement in hemoglobin A1c levels.3- 4 After a mean follow-up of 6.5 years in the Diabetes Control and Complications Trial (DCCT), a study designed to determine the effect of intensive diabetes therapy on the microvascular complications of type 1 diabetes, the prevalence of obesity—which is determined when the body mass index (BMI), which was greater than 27.8 kg/m2for men and greater than 27.3 kg/m2for women—reached 33.1% in the intensively treated subjects compared with 19.1% in the conventionally treated subjects.5 Despite this weight gain, lipid levels for the intensively treated group as a whole improved, including lower levels of dense low-density lipoprotein (LDL) and lipoprotein(a) (Lp[a]) at follow-up, compared with the conventionally treated group.6- 7 Recent studies of adults with type 1 diabetes have highlighted, however, that a higher BMI or waist-to-hip ratio (WHR) is associated with adverse lipid levels similar to those of centrally obese subjects who do not have diabetes and those with type 2 diabetes, eg, higher triglyceride levels, normal or slightly higher low-density lipoprotein cholesterol (LDL-C) levels, and lower high-density lipoprotein cholesterol (HDL-C) levels.2,8- 9 Coronary artery disease (CAD) is a leading cause of mortality in adult patients with type 1 diabetes.10- 11 Because CAD prevalence in type 1 diabetes has recently been shown to be associated with a higher triglyceride level, lower HDL-C levels, a greater WHR in men, and a higher BMI in women,12 it is important to understand the effect of weight gain from intensive diabetes therapy on these risk factors.
Background: A previous paper reported the 6-month comparison of weight loss and metabolic changes in obese adults randomly assigned to either a low-carbohydrate diet or a conventional weight loss diet. Objective: To review the 1-year outcomes between these diets. Design: Randomized trial. Setting: Philadelphia Veterans Affairs Medical Center. Participants: 132 obese adults with a body mass index of 35 kg/m 2 or greater; 83% had diabetes or the metabolic syndrome. Intervention: Participants received counseling to either restrict carbohydrate intake to <30 g per day (low-carbohydrate diet) or to restrict caloric intake by 500 calories per day with <30% of calories from fat (conventional diet). Measurements: Changes in weight, lipid levels, glycemic control, and insulin sensitivity. Results: By 1 year, mean (±SD) weight change for persons on the low-carbohydrate diet was -5.1 ± 8.7 kg compared with -3.1 ± 8.4 kg for persons on the conventional diet. Differences between groups were not significant (-1.9 kg [95% Cl, -4.9 to 1.0 kg]; P = 0.20). For persons on the low-carbohydrate diet, triglyceride levels decreased more (P = 0.044) and high-density lipoprotein cholesterol levels decreased less (P = 0.025). As seen in the small group of persons with diabetes (n = 54) and after adjustment for covariates, hemoglobin A 1c levels improved more for persons on the low-carbohydrate diet These more favorable metabolic responses to a low-carbohydrate diet remained significant after adjustment for weight loss differences. Changes in other lipids or insulin sensitivity did not differ between groups. Limitations: These findings are limited by a high dropout rate (34%) and by suboptimal dietary adherence of the enrolled persons. Conclusion: Participants on a low-carbohydrate diet had more favorable overall outcomes at 1 year than did those on a conventional diet. Weight loss was similar between groups, but effects on atherogenic dyslipidemia and glycemic control were still more favorable with a low-carbohydrate diet after adjustment for differences in weight loss.
Background: Low-carbohydrate diets remain popular despite a paucity of scientific evidence on their effectiveness. Objective: To compare the effects of a low-carbohydrate, ketogenic diet program with those of a low-fat, low-cholesterol, reduced-calorie diet. Design: Randomized, controlled trial. Setting: Outpatient research clinic. Participants: 120 overweight, hyperlipidemic volunteers from the community. Intervention: Low-carbohydrate diet (initially, <20 g of carbohydrate daily) plus nutritional supplementation, exercise recommendation, and group meetings, or low-fat diet (<30% energy from fat, <300 mg of cholesterol daily, and deficit of 500 to 1000 kcal/d) plus exercise recommendation and group meetings. Measurements: Body weight, body composition, fasting serum lipid levels, and tolerability. Results: A greater proportion of the low-carbohydrate diet group than the low-fat diet group completed the study (76% vs. 57%; P = 0.02). At 24 weeks, weight loss was greater in the low-carbohydrate diet group than in the low-fat diet group (mean change, -12.9% vs. -6.7%; P < 0.001). Patients in both groups lost substantially more fat mass (change, -9.4 kg with the low-carbohydrate diet vs. -4.8 kg with the low-fat diet) than fat-free mass (change, -3.3 kg vs. -2.4 kg, respectively). Compared with recipients of the low-fat diet, recipients of the low-carbohydrate diet had greater decreases in serum triglyceride levels (change, -0.84 mmol/L vs. -0.31 mmol/L [-74.2 mg/dL vs. -27.9 mg/dL]; P = 0.004) and greater increases in high-density lipoprotein cholesterol levels (0.14 mmol/L vs. -0.04 mmol/L [5.5 mg/dL vs. -1.6 mg/dL]; P < 0.001). Changes in low-density lipoprotein cholesterol level did not differ statistically (0.04 mmol/L [1.6 mg/dL] with the low-carbohydrate diet and -0.19 mmol/L [-7.4 mg/dL] with the low-fat diet; P = 0.2). Minor adverse effects were more frequent in the low-carbohydrate diet group. Limitations: We could not definitively distinguish effects of the low-carbohydrate diet and those of the nutritional supplements provided only to that group. In addition, participants were healthy and were followed for only 24 weeks. These factors limit the generalizability of the study results. Conclusions: Compared with a low-fat diet, a low-carbohydrate diet program had better participant retention and greater weight loss. During active weight loss, serum triglyceride levels decreased more and high-density lipoprotein cholesterol level increased more with the low-carbohydrate diet than with the low-fat diet.