New research published in the journal Physiology & Behavior suggests that calorie restriction does not discourage mice from getting their usual amount of exercise, challenging the common belief that cutting calories will hurt one’s workout.
The study included regular mice as well as mice that were selectively bred to enjoy running. In general, mice in a lab like to run on a wheel for several hours per day. Researchers spent three weeks collecting data on how much each group of mice ran every day as a baseline. Then, the two groups of mice were put on a 20% calorie-restricted diet for one week, followed by a 40% calorie restricted diet the next week. The goal of the study was to see how food restriction might change the desire or ability of the mice to perform physical activity.
The results showed that the regular mice did not decrease their baseline running distance on a 20% calorie deficit or a 40% calorie deficit. The mice who were bred to enjoy running did not decrease their running distance on a 20% calorie deficit, and they decreased it by only 11% while on a 40% calorie deficit. These mice were already running three times the distance of the normal mice every day, so this decrease was considered small. Interestingly, the body weight of both groups of mice was not significantly affected with a 20% calorie deficit and was affected fairly minimally by a 40% calorie deficit.
The authors of the study noted that the mice were likely still motivated to run because of the “runner’s high” of increased levels of dopamine and cannabinoids in the brain that are produced by running. The results of this study are encouraging for anyone on a diet; reducing your calorie intake won’t decrease your energy levels so much that you can’t complete your workout.
Sources: Physiology & Behavior, Science Daily