Comparative effects of dietary restriction of carbohydrate or fat on circulating adipokines

Abstract

We have shown in previous studies that a very low carbohydrate ketogenic diet (VLCKD) can ameliorate the metabolic disturbances of the insulin resistance syndrome (IRS) including adiposity, dyslipidemia, glucose and insulin control, inflammation, and vascular function. The favorable effects of a VLCKD on IRS may be modulated in part by altered adipokine secretion. We measured serum adipokines in 40 overweight men and women who consumed an ad libitum VLCKD (1504 kcal:%CHO:fat:protein=12:59:28) or a low fat diet (LFD) (1478 kcal: %CHO:fat:protein=56:24:20) for 12 wk. Compared to subjects in the LFD group, subjects consuming the VLCKD reduced body weight and adiposity. Serum leptin levels were reduced in subjects following the VLCKD compared to the LFD (−42 vs −18%). The significantly greater decrease in leptin in subjects following the VLCKD persisted after normalizing values to body mass and fat mass, indicating an increase in leptin sensitivity. Serum RBP4 levels are directly associated with insulin resistance, and were reduced more in subjects consuming the VLCKD compared to the LFD (−20 vs 5%). Plasminogen-activatorinhibitor-1 (PAI-1) has antifibrinolytic functions, and was also reduced more in subjects consuming the VLCKD compared to LFD (−34 vs −8%). Restriction of dietary carbohydrate is more effective than a low fat diet for reducing the adipokines leptin, RBP4, and PAI-1 and improving markers of IRS.