Acute appetite reduction associated with an increased frequency of eating in obese males

OBJECTIVE: To investigate the effects of altered feeding frequencies on the relationship between perceived hunger and subsequent food intake and appet ite control in obese men. DESIGN: Obese men reported in a fasted state in the morning to the laborato ry where an isoenergetic pre-load (4100 +/- 234 kJ, which was 33% average d aily energy requirement (ADER) of each subject) comprising 70% carbohydrate , 15% protein, and 15% fat was given. This was administered either as a SIN GLE meal, or divided evenly over 5 meals given hourly as a MULTI feeding pa ttern. Five hours after the first pre-load, an adlibitum test meal was give n to determine whether there was a difference in the amount of energy that was consumed between the two eating patterns. SUBJECTS: Seven non-diabetic, non-smoking, unrestrained obese men (age 37.4 +/- 18.5; BMI 40.02 +/- 10.93 kg/m(-2)) were recruited for this study. Sub jects were not told the precise reasons for this study but rather were info rmed that changes in blood glucose, insulin and free fatty acids with meal frequency were to be monitored. MEASUREMENTS: Blood glucose, serum insulin and free fatty acid (FFA) concen trations, and visual analogue scales (VAS) were measured prior to commencin g the feeding regime and thereafter hourly for 5 h. Thereafter an adlibitum meal was given. The weight (and energy content) of the food consumed, and the time taken to eat lunch were recorded. Following this adlibitum lunch, the same variables were determined again (15, 45, and 75 min post-test meal ). RESULTS: When given a SINGLE pre-load, 27% more (t = 2.651; P < 0.05) energ y was consumed in the ad libitum test meal (5261 +/- 1289 kJ) compared to t hat eaten after the MULTI pre-load (3763 +/- 1986 kJ). This increase in foo d intake occurred despite no significant change in subjective hunger rating s. Over the 315 min pre-load period, peak insulin concentrations were signi ficantly higher (F-6,F-72 = 7.95, P < 0.01) on the SINGLE treatment (171.2 +/- 129.8 mu U ml(-1)) than on the MULTI treatment (133.7 +/- 70.2 mu U ml( -1)). Serum insulin remained elevated for longer on the MULTI meal treatmen t, resulting in no difference in the area under the insulin curves between the two feeding treatments. There was a positive correlation (r = 0.87) bet ween the amount of energy consumed at lunch and insulin concentration befor e lunch in the SINGLE group. However, this relationship was not apparent wh en subjects were given the MULTI meal preload. CONCLUSION: Obese males fed an isoenergetic pre-load sub-divided into a mul ti-meal plan consumed 27% less at a subsequent adlibitum test meal than did the same men when given the pre-load as a single meal. Prolonged but atten uated increases in serum insulin concentration on the multi-meal programme may facilitate this acute reduction in appetite.