Christmas cheer and excess aren’t necessarily accompanied by mid-January gloom and weight gain, according to a new study. Researchers from the University of Bath have found that even during periods of overeating, daily exercise helps offset nutritional imbalances and unhealthy metabolic changes. Aside from mitigating post-holiday anxiety, the findings also broaden the current understanding of physiological responses to exercise. 

Prevailing research and epidemiological data show that weight gain is not the only negative outcome of overeating. Excess energy consumption is also tied to a range of physiological disruptions, including poor blood sugar control and an elevated risk of cardiovascular disease. However, research also suggests that such imbalances can be partially offset by regular exercise. In theory, this means that seasonal changes to one’s exercise routine may allow for “healthy overeating.”

The new study, which is published in the Journal of Physiology, sought to determine whether this represents a sensible approach to holiday excess. According to co-author Jean-Philippe Walhin, the investigation has so far yielded promising results. "Our research demonstrates that a short period of overconsumption and reduced physical activity leads to very profound negative changes in a variety of physiological systems — but that a daily bout of exercise stops most of these negative changes from taking place,” he said in a press release

For the study, the researchers enrolled 26 healthy young men in a a week-long experiment. Thirteen subjects were asked to exercise on a treadmill for 45 minutes each day. The other half of the group was asked to refrain from exercise and restrict their physical activity to less than 4,000 steps each day.

During the experiment, all subjects were asked to overeat. Notably, while exercising treatment subjects were asked to increase their caloric intake by 75 percent, non-exercising control subjects were asked to increase their intake by 50 percent. This way, everyone’s net daily calorie surplus remained the same. "A critical feature of our experiment is that we matched the energy surplus between groups — so the exercise group consumed even more energy and were still better off at the end of the week," senior author Dylan Thompson told reporters.

Subsequent analysis showed that the treatment group was significantly less likely to display the unhealthy metabolic changes recorded in the control group. They also had stable blood sugar levels and fewer “undesirable” genetic responses. Thompson concluded, "If you are facing a period of overconsumption and inactivity, which is probably quite common around Christmas time, then our study shows that a daily bout of exercise will prevent many of the negative changes from taking place even though you are gaining weight."

Source: Jean-Philippe Walhin, Judith D. Richardson, James A. Betts, and Dylan Thompson. “Exercise counteracts the effects of short-term overfeeding and reduced physical activity independent of energy imbalance in healthy young men.” J Physiol December 15, 2013 591 (24) 6231-6243.