EFFECTS OF CARBOHYDRATE AND LIPID ON RESTING ENERGY-EXPENDITURE, HEART-RATE, SLEEPINESS, AND MOOD

The effects of gastric infusions of fat and carbohydrate on physiologi cal and psychological measures were compared using a within subject de sign in 9 healthy subjects (6 males). Each subject received isovolaemi c rapid gastric infusions of sucrose solution (100% energy carbohydrat e), lipid emulsion (100% energy fat, 20% Intralipid), and a non-nutrie nt control (0.9% saline) in a randomised order. Nutrient infusions wer e isoenergetic, containing one-third of an individual subject's estima ted daily energy requirements (mean, 3227 kJ; range, 2479-3971 kJ). Me asures of heart rate (HR), energy expenditure (EE), mood, and sleepine ss were collected before the infusions and every 0.5 h for 3.5 h. Mean postingestive FIR, EE, and satiation were significantly greater after the nutrient infusions than after the control. Sucrose induced a rapi d increase in HR and EE, whereas lipid had a lesser and more delayed e ffect. Thirty minutes after the gastric infusions, HR and EE were sign ificantly higher after the sucrose than after the lipid and saline. He donic tone was greater and tension lower after the saline and sucrose infusions than after the lipid infusion. From 3 to 3.5 h after ingesti on, subjects felt significantly more sleepy after the lipid infusion t han they did at these times after the saline infusion, and significant ly more dreamy after the lipid infusion than they did after the sucros e infusion. In conclusion, the presence of lipid and sucrose in the in testine induces significant and differing physiological and psychologi cal effects, which are independent of cognitive and orosensory influen ces. (C) 1998 Elsevier Science Inc.