Can Exercise Protect from Short-term Overeating?

New study assesses protective effects of exercise on short-term overeating….

The study included 26 active men, mean age 25+/-7 years, who were either slated to eat 50% more energy than normal (50% overfed based on their resting metabolic rate (RMR)) for 7 days while restricting physical activity to <4,000 steps/day or to consume the same energy surplus based on RMR but while performing 45 minutes of vigorous treadmill running (daily exercise was defined as 5 min warm-up at 60% ˙VO2max then 45 min at 70% ˙VO2max). After a week of overeating +/- exercise, the group who was overfed but did not exercise had an increase in insulinaemic response to a 2 hour oral glucose tolerance test (OGTT) versus the overfed + exercise group. In fact, the 2 hour insulin AUC was two-fold greater than at baseline in the non-exercise group while insulin AUC was unaffected in the exercise group; similar results were demonstrated in the C-peptide response to the OGTT, the C-peptide response was significantly greater in the non-exercise group as compared to the exercise group.

Adipose tissue gene expression was also altered as a result of overfeeding/lack of exercise versus virtually no change in the exercise group. However, one should note that this study was very small with only 26 participants all of whom were young males (mean age 25 +/- 7 years) who were physically active (to be included in the study they had to be weight stable for previous 6 months and participate in vigorous-intensity exercise for 30 minutes or more, at least 3 times a week). While these inclusion criteria helped limit the timeline of the study, the "healthy" participants’ previous status could have impacted the outcomes.

Practice Pearls:

• Exercise helps people improve insulin resistance, glucose uptake, cardiovascular status and assist with weight loss.
• New research suggests that exercise, even in a time of short-term overeating, may have beneficial outcomes including improved glucose tolerance and decreases in adipose tissue gene changes as seen when over-eating is combined with lack of exercise
• The best way to stay healthy during the holiday season is to make smart food choices, limit caloric intake and continue (or start) exercising.

Walhin JP et al. Exercise counteracts the effects of short-term overfeeding and reduced physical activity independent of energy imbalance in healthy young men. J Physiol. 2013 Dec 15;591(Pt 24):6231-6243