Influence of glucose, medium- and long-chain triglyceride gastric loads and forced exercise on food intake and body weight in rats.

The purpose of this study was to examine the effect of oesophageal loads of glucose, medium (MCT)-and long-chain (LCT) triglycerides, plus treadmill exercise on food intake and body weight in rats. On test days, male rats were administered a gastric aqueous solution of glucose, MCT, LCT or water via an oesophageal tube. One hour later, the animals were forced to run on a treadmill for two hours at a speed of 20 m/min at 0% grade. At the beginning of the 12-hour dark cycle (at 7 p.m.) runners were returned to their cages. On control days, the same gastric loads were administered, but the animals remained in their cages. Food intake was continuously measured during both the dark and light periods. A reduction in body weight and total food intake was found after exercise. The food intake suppressing effect of exercise was seen in the first hours of the dark period. Following MCT and LCT oil stomach loads FI decrease was comparable but the latency of the effect varied. Stomach loads of MCT oil induced a reduction in FI within the 0-3 h of food availability whereas LCT oil suppressed intake during the 3-6-h dark period. This could be explained by their different metabolite fate.