Exercise May Prevent the Inflammation That Comes with Overeating

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Worried about eating too much over the holidays? Exercise may protect against the inflammation that can come with overindulging for a week, a very small new study suggests.
In the study, researchers looked at four lean, active adults in their early 20s who consumed 30 percent more calories than usual for one week. The participants were instructed to eat normally, with the extra calories coming from Boost shakes. All participants exercised aerobically for at least 150 minutes over the course of the week.
After the week was up, the researchers measured the participants' "glucose tolerance," which is a test of how well the body can use and break down the sugar glucose. Previous studies have shown that even one week of overeating can impair people's glucose tolerance.However, none of the adults in the study developed impaired glucose tolerance. [7 Foods You Can Overdose On]

The researchers also collected fat samples from the participants' bellies, in what Alison C. Ludzki, a Ph.D. student at the University of Michigan and the first author on the paper, likened to a "mini liposuction."
The samples showed that the study participants did not have increases in important markers of fat tissue inflammation, which otherwise would have been expected in people who consumed 30 percent extra calories for a week, the researchers said. This finding also indicates that exercise may protect against the inflammatory effects of short-term overeating, the researchers wrote in a preliminary write-up of their results.
The researchers hope to collect more data, in a larger number of participants, and also to compare these results against those of participants who overeat but do not exercise, in order to measure the strength of these effects, Ludzki said.
Inflammation is an immune reaction that can be triggered by a variety of factors, including excess eating, Ludzki told Live Science. In people who overeat, inflammation coincides with both weight gain and insulin resistance (a reduced sensitivity to insulin, the hormone that keeps blood sugar in check), but scientists aren't yet sure whether it causes insulin resistance and problems with metabolism or if it's merely associated with them and some other factor is at play. But in people with obesity, inflammation becomes a "sort of chronic immune response" in fat tissue, Ludzki said.
The results are still preliminary; so far, the lab has been able to test only four active adults, though the scientists have plans to perform additional testing on more participants, Ludzki said. She also noted that the study relied on self-reporting; the researchers provided the calorie supplement drink Boost to the participants, and they used a popular diet-tracking app to monitor their caloric intake. [Thanksgiving: 10 Tips for Sticking to Healthy Portions]
Ludzki said it also would be beneficial to look at the effects of overeating over longer periods of time, such as two or four weeks, to see if the association between exercise and protection against inflammation held steady. Future research could also investigate the effects of gender, the types of exercise that people do (aerobic versus anaerobic) and different food types on the results.
"It's important to know that it's still preliminary," Ludzki said of their results. She told Live Science that the lab was mainly trying to determine whether they would see results in a very short-term overeating intervention.