Acute effects of oral preloads with increasing energy density on gastric emptying, gut hormone release, thermogenesis and energy intake, in overweight and obese men

This study investigated the effect of high-and low-energy density preloads on gastrointestinal and metabolic factors, which act to regulate acute energy intake. Sixteen overweight and obese men (BMI range: 27.2-36.5 kg/m^2) each received 3 oral preloads in randomised order: i) high-energy-density, high-fat (1.5 kcal/g), ii) low-energydensity, high-fat (1.1 kcal/g), and iii) low-energy-density, high-protein (1.1 kcal/g). Over 180 min, gastric emptying, plasma glucagon-like peptide-1 concentrations, and diet-induced thermogenesis were assessed, and subsequent energy intake was determined. Total energy intake did not differ between preloads (high-energy-density, high-fat, 2059±72 kilocalories (kcal); low-energy-density, high-fat, 1876±91 kcal; and low-energy-density, highprotein, 1867±63 kcal). Gastric emptying was slower following the high-energy-density, high-fat preload (158±8 min) compared with the low-energy-density, high-protein preload (130±9 min) (p=0.05), but did not differ between the high-energy-density, high-fat and low-energy-density, high-fat (147±8 min) preloads. Plasma glucagon-like peptide-1 did not differ substantially between preloads. Diet-induced thermogenesis was lower following high-energy-density, high-fat (10.4±0.7 %) than low-energy-density, high-fat (14.9±1.2 %) and low-energydensity, high-protein (18.1±1.1 %) preloads (p