Enhanced thermogenesis and diminished deposition of fat in response to overfeeding with diet containing medium chain triglyceride

Abstract

The mechanism whereby overfeeding with diet containing medium chain triglyceride (MCT) results in diminished body weight and fat was studied. Fifteen male Sprague-Dawley rats were fitted under anesthesia with gastrostomy tubes and divided into two groups. One group was fed MCT diet, the other an isocaloric diet containing long chain triglyceride (LCT) in excess (150%) of spontaneous calorie intake. Both diets, fed for 6 wk, derived 50% of calories from fat. Basal and norepinephrine (25 µg/100 g) stimulated 0₂ consumption and CO₂ production, as well as metabolic rate were measured. After the rats were killed, total dissectible fat and fat cell size and number were determined. MCT rats gained 15% less weight than LCT controls (p < 0.001). Total dissectible fat was significantly lower (p < 0.001) in MCT group, as was mean adipocyte size (p < 0.001). Resting and maximal norepinephrine-stimulated 0₂ consumptions were 39.7 and 22.1% higher in MCT than in LCT group, respectively. Resting and norepinephrine-stimulated metabolic rates were 38.8 and 22.2% higher in MCT than LCT fed rats, respectively. Overfeeding MCT diet results in decreased body fat related to increased metabolic rate and thermogenesis.