Appetite dysfunction in obese males : evidence for role of hyperinsulinaemia in passive overconsumption with a high fat diet

To test the hypothesis that caloric and fat intake in a pre-load meal have no subsequent effects upon blood glucose and insulin concentrations, perceived hunger, subsequent food intake and appetite control in lean and obese men. Lean and obese men reported to the laboratory in the morning in a fasted state where they were subject to an eating test based on the pre-load-test meal paradigm, using a double-blind protocol. The breakfast pre-load was either a reduced caloric low-fat (LF) meal or an overfeeding high-fat (HF) meal. LF was 20% of each individual's average daily energy requirement (ADER) and comprised 60% carbohydrate, 27% protein, and 13% fat, whilst HF was adjusted to yield 55% of the ADER, and comprised 45% carbohydrate, 22% protein and 43% fat. The pre-loads on both trials were administered as one single mean, and were given in a random order. After 5(1/2) h, an ad libitum test-lunch was given to determine how much energy was consumed. Between the two meals, blood samples were collected and subjective hunger ratings were assessed hourly. These variables were measured at 30-min intervals for 75 min after the ad libitum meal. Twelve healthy men, six of whom were lean (BMI 22. 50+/-1.08 kg.m2) and six of whom were obese (BMI 39.05+/-11.63 kg. m2) were recruited. When given 55% of their ADER in a HF pre-load meal, the obese group consumed more energy (5426+/-1126 kJ; F1,20=11.45, P