UNCOUPLING THE EFFECTS OF ENERGY-EXPENDITURE AND ENERGY-INTAKE - APPETITE RESPONSE TO SHORT-TERM ENERGY DEFICIT INDUCED BY MEAL OMISSION AND PHYSICAL-ACTIVITY

The effects of two methods of inducing an acute energy deficit (exerci se and a low-energy breakfast) on appetite were investigated in 11 hea lthy females, all of whom were regular exercisers and regular breakfas t eaters. There were four experimental days: with exercise and a high- energy (500 kcal) breakfast (EHB), exercise and a low-energy (64 kcal) breakfast (ELB), no exercise and a high-energy breakfast (NEHB) and n o exercise and a low-energy breakfast (NELB). Hunger and moods were mo nitored each hour from 8 a.m. until 5 p.m. Energy and macronutrient in take were measured during an ad libitum lunch test meal 4 h after the exercise and breakfast. Heart rate was continuously monitored using th e Polar sport tester. The low-energy breakfasts (ELB and NELB) led to increased hunger during the morning and an increase in energy intake a t lunch compared with the high-energy breakfasts. Subjects also experi enced significantly more food cravings after LBs than after HBs. Exerc ise failed to have any significant effect on these variables. Thus, tw o methods of inducing a short-term energy deficit had markedly differe nt effects on appetite. The low-energy breakfast presumably fails to g enerate the inhibitory satiety signals induced by the 500 kcal breakfa st, whereas the metabolic effects of an exercise session failed to gen erate excitatory signals to hunger and food intake. (C) 1998 Academic Press.