Postprandial energy metabolism is modulated in response to a low-intensity walking exercise in fasted healthy individuals

Postprandial metabolism is a relevant indicator of overall metabolic health, which can be influenced by a single bout of exercise before food consumption. The present study examined the effects of an acute, fasted, low-intensity exercise on postprandial metabolism and appetite sensations. We hypothesized that exercise would induce an increase in postprandial fat oxidation, associated with better satiety responses. Twenty-two healthy adults (16 females) attended the laboratory twice separated by a minimum of 3 days to perform 2 conditions: (1) a control condition and (2) an exercise condition (EX) with a 30-minute low-intensity walking exercise performed before the breakfast (500-kcal fixed meal). Subjective appetite sensations were assessed before and up to 60 minutes after the meal in regular intervals. Energy expenditure and substrate oxidation were measured until 2 hours after the meal. Energy expenditure and carbohydrate oxidation were higher in the EX condition (condition effect: P < .01). There was no effect of exercise on appetite sensations and overall fat oxidation, but a higher increase in relative and absolute fat oxidation was observed from 15- to 45-minutes postmeal in EX compared with control (time × condition interaction effect: P < .05). In the EX condition only, postprandial satiety was associated positively with postprandial fat oxidation and negatively with carbohydrate oxidation. To conclude, a fasted low-intensity exercise induced an enhancement of postprandial metabolic flexibility through the modulation of fat oxidation. Substrate oxidation appeared to be related to satiety only after exercise, suggesting a specific regulation of appetite induced by exercise. This study explored the effects of low-intensity exercise in a fasted state on postprandial satiety and energy metabolism, compared to a control condition. The exercise impacted significantly the postprandial energy expenditure and substrate oxidation, and although it did not modify the appetite sensations, significant correlations between satiety and substrate oxidation were observed after exercise, but not after the control condition. ↗: increase, →: associated with, CHO: carbohydrate. [Display omitted]