Comparative effects of three popular diets on lipids, endothelial function, and C-reactive protein during weight maintenance

J Am Diet Assoc. 2009 Apr;109(4):713-7. doi: 10.1016/j.jada.2008.12.023.


Although popular diets focus on weight loss and their favorable biochemical and physiological effects, fewer investigations have evaluated the biological impact of these diets during weight maintenance. To study this issue, three popular diets-Atkins, South Beach, and Ornish-were tested in a randomized and counterbalanced crossover study between January and December 2006. Participants completed each of the three 4-week isocaloric dietary intervention phases followed by a 4-week washout period. They were weighed weekly and caloric adjustments made if weight change exceeded 1 kg. At the completion of each dietary phase, 3-day food records were analyzed, fasting blood sampled, and brachial artery reactivity testing performed. Eighteen adults completed all three isocaloric dietary phases. During the South Beach and Ornish maintenance phase, there were significant reductions in low-density lipoprotein cholesterol (11.8%; P=0.01, 16.6%; P=0.0006, respectively) compared to prediet baseline. In addition, in contrast to the Atkins maintenance phase, significant reductions in low-density lipoprotein cholesterol and apolipoprotein B levels were observed after the South Beach (P=0.003, P=0.05; repeated measures analyses of variance) and Ornish maintenance phases (P=0.0004, P=0.006, repeated measures analyses of variance). Brachial artery testing revealed an inverse correlation between flow-mediated vasodilatation and intake of saturated fat (r=-0.33; P=0.016). These data suggest that during weight maintenance, less favorable biological effects are observed during a simulated, high-fat Atkins diet when compared to the South Beach and Ornish diet. The findings support additional study in subjects with visceral obesity and the metabolic syndrome, in whom an increased risk of coronary disease at baseline may be accentuated with chronic consumption of a diet that exhibits unfavorable effects on lipids and endothelial function.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Analysis of Variance
  • Apolipoproteins B / blood
  • Brachial Artery / physiology
  • C-Reactive Protein / metabolism*
  • Cardiovascular Diseases / blood
  • Cardiovascular Diseases / epidemiology
  • Cardiovascular Diseases / prevention & control
  • Cholesterol, HDL / blood
  • Cholesterol, LDL / blood*
  • Cross-Over Studies
  • Diet Fads
  • Diet, Carbohydrate-Restricted*
  • Diet, Fat-Restricted*
  • Dietary Fats / administration & dosage
  • Dietary Fats / adverse effects
  • Dietary Fats / metabolism
  • Endothelium, Vascular / physiology*
  • Female
  • Humans
  • Male
  • Regional Blood Flow
  • Vasodilation / physiology


  • Apolipoproteins B
  • Cholesterol, HDL
  • Cholesterol, LDL
  • Dietary Fats
  • C-Reactive Protein