The effects of low-carbohydrate versus conventional weight loss diets in severely obese adults: one-year follow-up of a randomized trial.
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.


METHODS
Randomized trial.


METHODS
Philadelphia Veterans Affairs Medical Center.


METHODS
132 obese adults with a body mass index of 35 kg/m2 or greater; 83% had diabetes or the metabolic syndrome.


METHODS
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).


METHODS
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% CI, -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 A1c 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.


CONCLUSIONS
These findings are limited by a high dropout rate (34%) and by suboptimal dietary adherence of the enrolled persons.


CONCLUSIONS
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.
Stern
Linda
L
Philadelphia Veterans Affairs Medical Center, University of Pennsylvania Medical Center, and Drexel University College of Medicine, Philadelphia, Pennsylvania 19104, USA.
Iqbal
Nayyar
N
Seshadri
Prakash
P
Chicano
Kathryn L
KL
Daily
Denise A
DA
McGrory
Joyce
J
Williams
Monica
M
Gracely
Edward J
EJ
Samaha
Frederick F
FF
D000293:Adolescent; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D048909:Diabetes Complications; D003920:Diabetes Mellitus / Q000178:diet therapy; D018752:Diet, Fat-Restricted; D004038:Diet, Reducing; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007328:Insulin / Q000097:blood; D008055:Lipids / Q000097:blood; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications / Q000178:diet therapy; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications / Q000178:diet therapy* / Q000378:metabolism; D010349:Patient Compliance; D010352:Patient Dropouts; D015431:Weight Loss
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D007328:Insulin; D008055:Lipids