Obesity Abstracts

Background: There is increasing evidence that exercise training may facilitate weight management via improvements in appetite control. However, the meaningfulness of inter-individual variability in exercise-induced changes has recently been challenged.

Methods: This study examined the individual variability in body weight and composition, and markers of appetite in response to a supervised 12-week exercise intervention (2500 kcal/week) in inactive individuals with overweight and obesity (n=46, 30 females/16 males; BMI=30.6±3.8 kg/m²; age=43.2±7.5 years) compared to non-exercising controls (n=15; 9 females/6 males; BMI=31.4±3.7 kg/m²; age=41.4±10.7 years). Body weight and composition, hunger, daily food intake, food reward and eating behaviour traits were assessed at baseline and post-intervention. SD of the true individual response to the intervention (SD_IR) was calculated for each outcome. The mean body weight change and the individual response variability (2xSD_IR) was interpreted against a minimum clinically important difference of 2.5 kg. For other outcomes, the magnitude of SD_IR (standardized effect size; ES) was interpreted.

Results: The intervention produced a body weight loss of 1.8±2.9 kg in Exercisers (P<0.001), compared to a gain of 1.3±1.6 kg in Controls (P=0.06). The mean group difference (Exercise-Controls) in body weight was −3.1 kg (95%CI=−4.3 to −1.9 kg), with an SD_IR of 2.4 kg (95%CI=1.4 to 3.1 kg), a clinically meaningful small-to-moderate effect (ES=0.17, 95%CI=0.10 to 0.22). In the Exercisers, there was also true exercise-induced individual variability in body fat percentage (ES=0.22, 95%CI=0.06 to 0.30), fat mass (ES=0.21, 95%CI=−0.07 to 0.31), restraint (ES=0.74, 95%CI=0.45 to 0.95), susceptibility to hunger (ES=0.46, 95%CI=−0.17 to 0.68) and binge eating (ES=0.47, 95%CI=0.23 to 0.63). For fasting and daily hunger ratings, food intake, food reward and disinhibition, both groups had a high degree of variability relative to the SD_IR, which suggests individual variability independent of the exercise intervention. Outcomes need to be interpreted with caution as sample size was small and uncertainty high.

Conclusions: These data suggest existence of true inter-individual variability in exercise-induced weight loss and some markers of appetite that was small to large in magnitude.

Keywords: Exercise, inter-individual variability, weight loss, body composition, appetite

Disclosures: None.