Effect of orosensory stimulation on postprandial thermogenesis in humans

This study assessed the effects of orosensory stimulation by equipalatable stimuli that differed in macronutrient content (lipid and carbohydrate) on postprandial thermogenesis. Sixteen healthy, normal-weight adults (eight males, eight females) participated in six test sessions conducted weekly. The test sessions were administered randomly after overnight fasts and included: ingestion of 50 g of butter in capsules (to avoid oral stimulation with lipids) and 500 ml of water in 15 min followed by no oral stimulation or oral stimulation with a cracker or one of the following foods on a cracker-butter, unsaturated fatty acid (UFA) margarine, jelly, UFA margarine+jelly. Sensory stimulation entailed masticating and expectorating approximately 5.0 g samples of each stimulus every 3 min for 110 min. Blood was drawn immediately after preload ingestion and at minutes 35, 85, 200, 320, and 440 postloading and was analyzed for insulin, glucagon, and glucose. No significant treatment differences were observed for thermogenesis or oxidation of carbohydrate or lipid. Insulin, glucagon, and glucose concentrations were not different between treatments. These data suggest that orosensory stimulation with stimuli differing in lipid and carbohydrate content, but rated similarly in palatability, does not elicit an increased or differential diet-induced thermogenic response.