Did you gain weight while marathon training? Read this to find out why. Training for half and full marathons is common in the spring, summer and fall. One of the side effects of this is weight gain which is often unexpected due to the amount of calories expended while training. Science is now beginning to understand how and what the body does to adapt to increased exercise according to a recent NY Times article. Apparently, regular high level exercise causes the body to become more efficient, and as a result, burn fewer calories when running. Check out the article below Pushing the Limits of Human Endurance When we work out rigorously on a regular basis, our bodies adjust to limit our ability to expend energy, a new study shows. By Gretchen Reynolds June 12, 2019 Our bodies seem to adjust to prolonged, repeated physical exertion and its energy demands by burning fewer — instead of more — calories over the course of the day, even if our exertions continue at the same level, according to a surprising new study of energy expenditure conducted during a 20-week running race across the United States. The study is among the first to quantify the upper limits of human daily energy expenditure and endurance, whether someone is running across the country, competing in the Tour de France or pregnant. The study’s counterintuitive findings have implications for athletes, our understanding of human evolution, and our hopes that training for a marathon or other endurance event will help us shed weight. Level training should in theory cause you to lose weight, however the body is quite adaptive and over many years, we have adapted to be able to become more efficient with increased activity. Read more