title: A low-carbohydrate as compared with a low-fat diet in severe obesity.
abstract: BACKGROUND
  The effects of a carbohydrate-restricted diet on weight loss and risk factors for atherosclerosis have been incompletely assessed.
  
  
  METHODS
  We randomly assigned 132 severely obese subjects (including 77 blacks and 23 women) with a mean body-mass index of 43 and a high prevalence of diabetes (39 percent) or the metabolic syndrome (43 percent) to a carbohydrate-restricted (low-carbohydrate) diet or a calorie- and fat-restricted (low-fat) diet.
  
  
  RESULTS
  Seventy-nine subjects completed the six-month study. An analysis including all subjects, with the last observation carried forward for those who dropped out, showed that subjects on the low-carbohydrate diet lost more weight than those on the low-fat diet (mean [+/-SD], -5.8+/-8.6 kg vs. -1.9+/-4.2 kg; P=0.002) and had greater decreases in triglyceride levels (mean, -20+/-43 percent vs. -4+/-31 percent; P=0.001), irrespective of the use or nonuse of hypoglycemic or lipid-lowering medications. Insulin sensitivity, measured only in subjects without diabetes, also improved more among subjects on the low-carbohydrate diet (6+/-9 percent vs. -3+/-8 percent, P=0.01). The amount of weight lost (P<0.001) and assignment to the low-carbohydrate diet (P=0.01) were independent predictors of improvement in triglyceride levels and insulin sensitivity.
  
  
  CONCLUSIONS
  Severely obese subjects with a high prevalence of diabetes or the metabolic syndrome lost more weight during six months on a carbohydrate-restricted diet than on a calorie- and fat-restricted diet, with a relative improvement in insulin sensitivity and triglyceride levels, even after adjustment for the amount of weight lost. This finding should be interpreted with caution, given the small magnitude of overall and between-group differences in weight loss in these markedly obese subjects and the short duration of the study. Future studies evaluating long-term cardiovascular outcomes are needed before a carbohydrate-restricted diet can be endorsed.
authors.affiliation: Philadelphia Veterans Affairs Medical Center, University of Pennsylvania Medical Center, Philadelphia, USA. rick.samaha@med.va.gov
authors.forename: Frederick F
authors.initials: FF
authors.lastname: Samaha
authors.forename: Nayyar
authors.initials: N
authors.lastname: Iqbal
authors.forename: Prakash
authors.initials: P
authors.lastname: Seshadri
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Chicano
authors.forename: Denise A
authors.initials: DA
authors.lastname: Daily
authors.forename: Joyce
authors.initials: J
authors.lastname: McGrory
authors.forename: Terrence
authors.initials: T
authors.lastname: Williams
authors.forename: Monica
authors.initials: M
authors.lastname: Williams
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Gracely
authors.forename: Linda
authors.initials: L
authors.lastname: Stern
mesh_terms: D001161:Arteriosclerosis; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D003920:Diabetes Mellitus / Q000097:blood / Q000178:diet therapy; D018752:Diet, Fat-Restricted; D004038:Diet, Reducing / Q000379:methods*; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008055:Lipids / Q000097:blood; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000178:diet therapy; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000178:diet therapy*; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood; D015431:Weight Loss
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D008055:Lipids; D014280:Triglycerides