Effect of a low-carbohydrate diet versus a low-fat, calorie-restricted diet on adipokine levels in obese, diabetic participants

Abstract

The effect of dietary macronutrient composition on adipokine concentrations remains unclear. Greater reductions in leptin have been reported in participants who followed low-carbohydrate versus low-fat diets, although these studies did not adjust for the important effects of weight loss on adipokines. We investigated the effect of macronutrient composition on adipokine levels in 144 obese, diabetic participants who were randomly assigned to a low- carbohydrate (< 30 g/day) or low-fat diet (≤ 30% of calories from fat with a deficit of 500 kcal/day). Weight, adipokines, and dietary intake were assessed at baseline and 6 months. Complete data were available for 79 participants. At month 6, weight, leptin, adiponectin, and tumor necrosis factor-α concentrations did not differ significantly between groups (P > 0.05 for all variables). However, significant changes in leptin and adiponectin occurred over time (P < 0.001 and P < 0.012, respectively). Modest weight loss, rather than macronutrient composition, likely accounted for the favorable changes observed in leptin and adiponectin over time.

Keywords:

• diet
• adipokine
• obesity
• diabetes
• carbohydrate
• hormone

Acknowledgments

This study is dedicated to the memory of Frederick F Samaha, MD, in recognition of his many contributions to this research. We gratefully acknowledge the contributions of Rosa Kim, BS, and Sara Ali, MD, for their assistance with study management. We thank Heather Collins, PhD, from the Diabetes Endocrinology Research Center at the University of Pennsylvania, for performing the adipokine assays. We thank J Graham Thomas, PhD, for his assistance with the statistical analysis. Grant Support: VA Merit Review Entry Program.

Disclosure

The authors have no conflict of interest to disclose. Dr Iqbal is currently employed at Bristol-Myers Squibb, but remains an adjunct faculty member at the University of Pennsylvania School of Medicine. He was a full-time faculty member at the University of Pennsylvania and at the Philadelphia Veterans Affairs Medical Center during the period in which the study was conducted.