A low-carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia: a randomized, controlled trial.
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.


METHODS
Randomized, controlled trial.


METHODS
Outpatient research clinic.


METHODS
120 overweight, hyperlipidemic volunteers from the community.


METHODS
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.


METHODS
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.


CONCLUSIONS
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.
Yancy
William S
WS
Center for Health Services Research in Primary Care, Department of Veterans Affairs Medical Center, and Duke University Medical Center, Durham, North Carolina 27705, USA.
Olsen
Maren K
MK
Guyton
John R
JR
Bakst
Ronna P
RP
Westman
Eric C
EC
D000273:Adipose Tissue / Q000033:anatomy & histology; D000293:Adolescent; D000328:Adult; D000368:Aged; D001823:Body Composition; D018752:Diet, Fat-Restricted; D004038:Diet, Reducing; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D015444:Exercise; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000150:complications / Q000178:diet therapy* / Q000378:metabolism; D007659:Ketones / Q000652:urine; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000178:diet therapy* / Q000378:metabolism; D010349:Patient Compliance; D010352:Patient Dropouts; D015431:Weight Loss
D004040:Dietary Carbohydrates; D007659:Ketones; D008055:Lipids