A new UC Riverside study demonstrates that calorie restriction doesn't deter mice from exercising, challenging the belief that dieting drains workout energy. The study, published in the journal Physiology & Behavior, shows that cutting calories by 20% did not significantly reduce the distance that mice voluntarily chose to run each day. The researchers set out to understand what happens to mice when the amount of food available to them is reduced.
The findings, they hoped, would be relevant to wild animals that do not always get as much food as they want on a given day, and also to humans, whose doctors often prescribe dieting. It is somewhat difficult to obtain accurate data on the amount of voluntary exercise that humans engage in. Though it is easy to categorize what people recognize as voluntary exercise, like a trip to the gym, there is much gray area that's hard to quantify, such as walking to a cafeteria to purchase lunch instead of eating a meal from a nearby lunch box.
Tracking what lab mice choose to do is much easier, and lab mice generally like to run on wheels for many hours per day. In this study, researchers saw the mice chose to run at similar levels, regardless of how much they ate. Voluntary exercise was remarkably resistant to reducing the amount of food by 20% and even by 40%.
They just kept running." Theodore Garland, Jr., UCR biologist and corresponding study author The researchers spent three weeks getting a baseline level of running activity for the mi.