title: Lack of suppression of circulating free fatty acids and hypercholesterolemia during weight loss on a high-fat, low-carbohydrate diet.
abstract: BACKGROUND
  Little is known about the comparative effect of weight-loss diets on metabolic profiles during dieting.
  
  
  OBJECTIVE
  The purpose of this study was to compare the effect of a low-carbohydrate diet (< or =20 g/d) with a high-carbohydrate diet (55% of total energy intake) on fasting and hourly metabolic variables during active weight loss.
  
  
  METHODS
  Healthy, obese adults (n = 32; 22 women, 10 men) were randomly assigned to receive either a carbohydrate-restricted diet [High Fat; mean +/- SD body mass index (BMI; in kg/m(2)): 35.8 +/- 2.9] or a calorie-restricted, low-fat diet (High Carb; BMI: 36.7 +/- 4.6) for 6 wk. A 24-h in-patient feeding study was performed at baseline and after 6 wk. Glucose, insulin, free fatty acids (FFAs), and triglycerides were measured hourly during meals, at regimented times. Remnant lipoprotein cholesterol was measured every 4 h.
  
  
  RESULTS
  Patients lost a similar amount of weight in both groups (P = 0.57). There was an absence of any diet treatment effect between groups on fasting triglycerides or on remnant lipoprotein cholesterol, which was the main outcome. Fasting insulin decreased (P = 0.03), and both fasting (P = 0.040) and 24-h FFAs (P < 0.0001) increased within the High Fat group. Twenty-four-hour insulin decreased (P < 0.05 for both groups). Fasting LDL cholesterol decreased in the High Carb group only (P = 0.003). In both groups, the differences in fasting and 24-h FFAs at 6 wk were significantly correlated with the change in LDL cholesterol (fasting FFA: r = 0.41, P = 0.02; 24-h FFA: r = 0.52, P = 0.002).
  
  
  CONCLUSIONS
  Weight loss was similar between diets, but only the high-fat diet increased LDL-cholesterol concentrations. This effect was related to the lack of suppression of both fasting and 24-h FFAs.
authors.affiliation: University of Colorado, Aurora, CO, USA. teri.hernandez@ucdenver.edu
authors.forename: Teri L
authors.initials: TL
authors.lastname: Hernandez
authors.forename: Julie P
authors.initials: JP
authors.lastname: Sutherland
authors.forename: Pamela
authors.initials: P
authors.lastname: Wolfe
authors.forename: Marybeth
authors.initials: M
authors.lastname: Allian-Sauer
authors.forename: Warren H
authors.initials: WH
authors.lastname: Capell
authors.forename: Natalie D
authors.initials: ND
authors.lastname: Talley
authors.forename: Holly R
authors.initials: HR
authors.lastname: Wyatt
authors.forename: Gary D
authors.initials: GD
authors.lastname: Foster
authors.forename: James O
authors.initials: JO
authors.lastname: Hill
authors.forename: Robert H
authors.initials: RH
authors.lastname: Eckel
mesh_terms: D000328:Adult; D008078:Cholesterol, LDL / Q000097:blood; D050528:Diet, Carbohydrate-Restricted; D018752:Diet, Fat-Restricted; D004038:Diet, Reducing; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage / Q000009:adverse effects*; D002149:Energy Intake; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood / Q000209:etiology*; D007328:Insulin / Q000097:blood; D008074:Lipoproteins / Q000097:blood; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000178:diet therapy*; D014280:Triglycerides / Q000097:blood; D015431:Weight Loss / Q000502:physiology*
chemical_list: D008078:Cholesterol, LDL; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D008074:Lipoproteins; D014280:Triglycerides