Eight healthy males of age 22.9+/-4.2 years (mean+/-SD) and body weight 73.26+/-11.50 kg, with BMI of 23.11+/-2.84 kg/m(2)underwent two different eating meal frequency patterns on 2 separate days. On both days they were fed approximately 33.3% of their average daily energy requirements as a breakfast pre-load meal: served either as a single meal (SINGLE) or divided into five equal portions (served hourly) (MULTI). Five and a half hours after the initial meal, an ad libitum meal was served. Venous blood was tested to determine plasma glucose and serum insulin concentrations every hour until the ad libitum lunch, and at 15-, 45- and 75-min after lunch. Visual analogue scales (VAS) were completed every hour until the ad libitum lunch, and at 15-, 45- and 75-min after lunch as a measure to determine hunger, appetite and satiety indices. Although both groups were fed isocaloric and identical macronutrient "breakfast pre-loads" (3450+/-466 kJ), the SINGLE group consumed 26.6% more (p<0.02) energy in the ad libitum lunch (5111+/-1502 kJ vs. 3752+/-893 kJ) than the MULTI group did. The pre-load feeding pattern had no effect on blood glucose responses throughout the trial. Following the larger SINGLE pre-load, serum insulin concentration rose to a higher (p<0.01) level compared to the first of the MULTI pre-load meals (123.04+/-61.51 microIU/ml vs. 37. 30+/-26.65 microIU/ml SINGLE vs. MULTI, respectively). Serum insulin rose to a higher (p<0.01) level following the fifth and final of the MULTI pre-load meals compared to the serum insulin levels in the SINGLE group at the same time into the trial (74. 21+/-51.64 microIU/ml vs. 24.98+/-13.46 microIU/ml MULTI vs. SINGLE, respectively). Despite consuming more energy in the ad libitum lunch, the SINGLE group showed no difference in serum insulin concentration following the ad libitum lunch compared to the insulin response of the MULTI group. These data suggest that when the nutrient load was spread into equal amounts and consumed evenly through the day in lean healthy males, there was an enhanced control of appetite. This greater control of satiety when consuming smaller multiple meals may possibly be linked to an attenuation in insulin response although clearly both other physical (gastric stretch) and physiological (release of gastric hormones) factors may also be affected by the periodicity of eating.
Copyright 1999 Academic Press.