A Randomized Study Comparing the Effects of a Low‐Carbohydrate Diet and a Conventional Diet on Lipoprotein Subfractions and C‐reactive Protein Levels in Patients With Severe Obesity

Purpose: To compare the effects of a low‐carbohydrate diet and a conventional (fat‐ and calorie‐restricted) diet on lipoprotein subfractions and inflammation in severely obese subjects. Methods: We compared changes in lipoprotein subfractions and C‐reactive protein levels in 78 severely obese subjects, including 86% with either diabetes or metabolic syndrome, who were randomly assigned to either a low‐carbohydrate or conventional diet for 6 months. Results: Subjects on a low‐carbohydrate diet experienced a greater decrease in large very low‐density lipoprotein (VLDL) levels (difference =–0.26 mg/dL, p = .03) but more frequently developed detectable chylomicrons (44% vs 22%, p = .04). Both diet groups experienced similar decreases in the number of low‐density lipoprotein (LDL) particles (difference = –30 nmol/L, p = .74) and increases in large high‐density lipoprotein (HDL) concentrations (difference = 0.70 mg/dL, p = .63). Overall, C‐reactive protein levels decreased modestly in both diet groups. However, patients with a high‐risk baseline level (>3 mg/dL, n = 48) experienced a greater decrease in C‐reactive protein levels on a low‐carbohydrate diet (adjusted difference = –2 mg/dL, p = .005), independent of weight loss. Conclusions: In this 6‐month study involving severely obese subjects, we found an overall favorable effect of a low‐carbohydrate diet on lipoprotein subfractions and on inflammation in high‐risk subjects. Both diets had similar effects on LDL and HDL subfractions. ( Am J Med. 2004;117:398–405.)