The Effects of Low-Carbohydrate Versus Conventional Weight Loss Diets in Severely Obese Adults: One-Year Follow-Up of a Randomized Trial

Ann Intern Med. 2004 May 18;140(10):778-85. doi: 10.7326/0003-4819-140-10-200405180-00007.

Abstract

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/m2 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% 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.

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.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Blood Glucose / metabolism
  • Diabetes Complications
  • Diabetes Mellitus / diet therapy
  • Diet, Fat-Restricted*
  • Diet, Reducing*
  • Dietary Carbohydrates / administration & dosage*
  • Female
  • Follow-Up Studies
  • Humans
  • Insulin / blood
  • Lipids / blood
  • Male
  • Metabolic Syndrome / complications
  • Metabolic Syndrome / diet therapy
  • Middle Aged
  • Obesity, Morbid / complications
  • Obesity, Morbid / diet therapy*
  • Obesity, Morbid / metabolism
  • Patient Compliance
  • Patient Dropouts
  • Weight Loss

Substances

  • Blood Glucose
  • Dietary Carbohydrates
  • Insulin
  • Lipids