The CDC reports over 2/3 of Americans are either overweight or obese with less than 1/3 reaching the recommended 150 minutes of exercise each week (21 minutes per day). Weight loss is a complicated, multifactorial process but many researchers recommend the combination of diet and exercise to reduce body mass. Diet has the greatest impact based on its’ relative ease compared with an equivalent caloric deficit from exercise, but prior research has shown better adherence and long term success when these cuts are combined with exercise.
Many exercise participants enjoy the early benefits, including weight loss, with exercise only to become frustrated at an eventual lack of progress. Our bodies have a remarkable ability to conserve energy and often will compensate for the increased energy expenditure of exercise by reducing activity the rest of the day or by increasing appetite. Researchers have shown these compensations are most impactful with lesser amounts of exercise and have less impact with greater intensity and longer durations of exercise. Thus, making longer and harder exercise sessions more effective for weight loss.
A recent randomized controlled trial added additional confirmation on the topic of weight loss and exercise (Flack et al. Am J Physiol Regul Comp Physiol. 2018). Authors randomized overweight to obese men and women to one of two exercise groups. The first group walked 150 minutes/week recommended by national guidelines, but the second group walked 300 minutes/week (42 minutes per day). Each participant exercised briskly 5 days a week for 12 weeks. Authors reported the 300 minute group lost an average of 6 lbs, but no weight loss was found in the 150 minute group due to greater amounts of energy compensation in the shorter duration group. Walkers are encouraged to work with their medical provider on nutrition and diet strategies, as well as, lengthening their duration of walks to optimize weight loss.