Effect of aerobic training before and after a meal on serum acylated ghrelin level, daily energy intake and single exercise energy expenditure in overweight men

In this study the effects of a single training session of overweight men before and after a meal on serum acetylated ghrelin levels, daily energy intake and the exercise energy expenditure were compared.

In this  semi experimental study, 30 overweight men (Mean and SD age of 25.2±3.54 years, BMI 27.96±3.64 kg/m2, weight 83.2±5.8 kg) were randomized into three groups (n = 10) including before lunch training, post lunch training and control. Experimental groups performed eight weeks, three sessions/wk of aerobic training sessions, consisted of 25 to 40 min of treadmill running and/or cycling at maximal fat oxidation intensity, either an hour prior to or two hours after a meal. Exercise energy expenditure, daily caloric intake and fasting serum acylated ghrelin levels in response to a single exercise session were measured as data in both pre and post-test occasions.

A single training session either pre or post lunch meal increases serum acylated ghrelin level (P≤ 0/001), exercise energy expenditure (P≤ 0/001) and daily caloric intake (P≤ 0/001); indicating a compensatory energy intake which lowers the expected exercise-induced weight loss.However, pre meal exercise leads to more remarkable increases in exercise energy cost (P≤ 0/001) concomitant with an elevated fasting serum acylated ghrelin levels (P≤ 0/001).

If appetite suppression is the only goal for exercise, it seems that exercise training should be performed after meals, and if maximizing each session’s energy cost is the case, it is better to practice before meals.