Physical activity is associated with accelerated gastric emptying and increased ghrelin in obesity

Background: Rapid gastric emptying, increased food intake, and alterations in gastrointestinal hormones are associated with obesity. The effect of regular physical activity (PA) on food intake, gastric emptying (GE), gastric accommodation, and gastrointestinal (GI) hormones in adults with obesity remains unclear. Our aim was to compare, at time of presentation, weight trends, eating behavior, GE, and GI hormone levels among individuals with obesity who engage in regular PA compared to those who do not. Methods: In 270 participants with obesity, we performed validated measurements of GI phenotypes: GE of solids and liquids, gastric volume (GV) during fasting and after consumption of 200 mL Ensure®, satiety by kcal intake (T-kcal) during a buffet meal, satiation (volume to fullness [VTF] and maximal tolerated volume [MTV]) of a liquid nutrient, and plasma levels of fasting and postprandial GLP-1, PYY, CCK, and ghrelin. Physical Activity Stages of Change Questionnaire was used to assess whether participants were regularly PA or not. Key results: PA was associated with lower BMI (Δ 2.01 kg/m², P =.001) and body weight (Δ 4.42 kg, P =.0278). GE of solids (T-50% Δ 7.54 min, P =.021) and liquids (T-50% Δ 2.99 min, P =.029%) was significantly more rapid in physically active participants. PA was also associated with relatively higher postprandial ghrelin AUC (Δ 10.4 pg/mL, P =.015). There was no significant difference in postprandial satiation, satiety, GV, or other GI hormones (CCK, PYY, or GLP-1) between groups. Conclusions & Inferences: Physical activity is associated with lower BMI, but faster GE and higher postprandial ghrelin levels, two factors that are also associated with obesity.