Appetite Control Is Improved by Acute Increases in Energy Turnover at Different Levels of Energy Balance

BACKGROUND:Weight control is hypothesized to be improved when physical activity and energy intake are both high (high energy turnover, ET).

OBJECTIVE:The impact of three levels of ET on short-term appetite control is therefore investigated at fixed levels of energy balance.

DESIGN:In a randomized cross-over trial, 16 healthy adults (25.1 ±3.9 y; BMI 24.0 ±3.2 kg/m2) spent 4 x 3 daylong protocols in a metabolic chamber. Four conditions of energy balance (ad libitum energy intake, zero energy balance, -25% caloric restriction and +25% overfeeding) were each performed at three levels of ET (PAL 1.3 low, 1.6 medium and 1.8 high ET; by walking on a treadmill). Levels of appetite hormones ghrelin, GLP-1 and insulin (tAUC) were measured over 14 hours. Subjective appetite ratings were assessed by Visual Analogue Scales.

RESULTS:Compared to high ET, low ET led to decreased GLP-1 (at all energy balance conditions: p<0.001) and increased ghrelin concentrations (caloric restriction and overfeeding: p<0.001) which was consistent with higher feelings of hunger (zero energy balance: p<0.001) and desire to eat (all energy balance conditions: p<0.05) and a positive energy balance during ad libitum intake (+17.5%; p<0.001).

CONCLUSION:Appetite is regulated more effectively at a high level of energy turnover, whereas overeating and consequently weight gain is likely to occur at low levels of energy turnover. In contrast to the prevailing concept of body weight control, the positive impact of physical activity is independent from burning up more calories and is explained by improved appetite sensations.