A Carbohydrate-Restricted Diet Alters Gut Peptides and Adiposity Signals in Men and Women with Metabolic Syndrome ,

Abstract

Carbohydrate-restricted diets have been shown to enhance satiation- and other homeostatic-signaling pathways controlling food intake and energy balance, which may serve to reduce the incidence of obesity and metabolic syndrome. This study was designed as a correlational, observational investigation of the effects of a carbohydrate-restricted diet on weight loss and body fat reduction and associated changes in circulating leptin, insulin, ghrelin, and cholecystokinin (CCK) concentrations in overweight/obese patients (4 men and 16 women) with metabolic syndrome. Subjects received clinical instruction on the initiation and maintenance of the commercial South Beach Diet, consisting of 2 phases: Phase I (initial 2 wk of the study) and Phase II (remaining 10 wk). Participants showed a decrease (P < 0.05) in body weight (93.5 α 3.6 kg vs. 88.3 α 3.4 kg), BMI (33.9 α 1.3 kg/m2 vs. 32.0 α 1.3 kg/m2), waist circumference (112.8 α 2.8 cm vs. 107.7 α 3.0 cm), and total percent body fat (40.2 α 1.5% vs. 39.2 α 1.5%) by study completion. Plasma fasting insulin and leptin concentrations decreased significantly from baseline concentrations (139.1 α 12.2 pmol/L and 44.1 α 4.5 μg/L, respectively) by the end of Phase I (98.6 α 2.6 pmol/L and 33.3 α 4.1 μg/L, respectively). Plasma fasting ghrelin concentrations significantly increased from baseline (836.7 α 66.7 ng/L) by Phase II (939.9 α 56.8 ng/L). The postprandial increase in plasma CCK concentrations (difference in plasma CCK concentrations from fasting to postprandial) after Phase I (2.4 α 0.3 pmol/L) and Phase II (2.5 α 0.4 pmol/L) was significantly greater than the postprandial increase at baseline (1.1 α 0.5 pmol/L). Collectively, these results suggest that in patients with metabolic syndrome, improved adiposity signaling and increased postprandial CCK concentrations may act together as a possible compensatory control mechanism to maintain low intakes and facilitate weight loss, despite an increase in fasting ghrelin concentrations and subjective measures of hunger.