What kind of exercise is best for weight loss?
Over the years, there have been many exercise programs claiming to be superior to others for helping people get fit and lose weight. Examples of these include CrossFit, HYROX, Orange Theory, Peloton, F45, P90X, etc. It seems clear these fitness companies want to help you improve body composition (improve lean body mass). But, what exactly does research tell us about specific types of exercise and their benefits in terms of body composition and weight loss?
First, exercise does not help you lose weight! Have I shocked you enough? Then let’s back up a bit. SOME forms of exercise may help you lose weight, BUT weight loss is mostly determined by what you eat. As a favorite patient once said, “Doc, I can out eat any exercise program you put me on.” Well, that is true for most people if they are trying to lose weight through aerobic or prolonged HIIT exercise.
If you are trying to lose weight, you need to focus on what and how much you are eating, first and foremost. There is no weight loss without CHANGE. Why would your weight change if you don’t change either what you are eating, how much you are eating, or both?
A related question is, can exercise help you lose weight? Yes! Research suggests that resistance training is superior to aerobic exercise in terms of improving body composition. There are several reasons for this:
Increase in resting metabolic rate (RMR): As resistance training will overtime increase muscle mass, one’s resting metabolic rate (amount of calories burned over a 24 hour time period at rest) will increase as muscle burns roughly 4x the amount of calories per hour than the same amount of fat. It has been shown that a pound of muscle burns about 8 calories per day whereas a pound of fat burns only about 2 calories per day. When aerobic exercise does cause weight loss, it typically causes loss of both fat mass and muscle mass so it may paradoxically have a negative effect on RMR.
Excess Post-Exercise Oxygen Consumption (EPOC): Resistance training can have a pronounced effect on EPOC, otherwise known as the afterburn effect. The afterburn effect is the increased amount of Oxygen consumed post exercise. Due to the microtrauma of muscle fibers caused by a strength workout, oxygen and energy are required to repair this tissue. It’s been shown that there can be an increase in oxygen consumption up to 48 hours after an intense workout. With low intensity aerobic exercise this effect will only last minutes to hours. Of note, this same prolonged beneficial effect is noticed after high intensity interval training (HIIT workouts) as well.
Hormonal changes: Resistance training will likely cause an increase in one’s testosterone and growth hormone levels. Both of these hormones are key regulators of fat burning and muscle growth. Again, this is important because muscle burns 4x as many calories as fat. Aerobic exercise does not offer the same hormonal advantages that strength training does.
Increase in insulin sensitivity: Both strength training and aerobic exercise offer tremendous benefits in insulin sensitivity and are extremely important in combatting insulin resistance. Insulin resistance is the first step towards developing type II diabetes and can often be reversed if action is taken early.
Aerobic exercise and increased caloric intake: Have you ever noticed how hungry you are after a long bike ride, run, or hike? While aerobic exercise undoubtedly does cause an increase in calorie burn, this increase usually leads to increased eating and caloric intake following exercise. Have you ever noticed how you DON’T get that hungry after strength training? Strength training just does not generate the same feeling of hunger after working out. The reasons for this are clear. Aerobic exercise leads to increased levels of ghrelin, the “hunger hormone.” Strength training increases the concentration of peptide YY and the famous GLP-1, which are hunger suppressing hormones.
If you are already weight training and you are still having issues with body composition, common areas needing some work include eating a very nutrient dense diet, optimizing your sleep and gut health, and getting your hormone levels evaluated. It is difficult to lose body fat without getting these things in order first.
While this article focuses on strength training and its advantages for desired weight loss, I am by no means discouraging aerobic exercise. In fact, low intensity aerobic exercise and improvement in cardiovascular fitness is arguably the single most important aspect of a longevity and wellness program and metabolic health. VO2 max (a marker that we can measure by doing a test during exercise) has been shown to be one of the best predictors of all cause mortality. VO2 max can be increased at any age through a well planned exercise program.
If you’re interested in improving your fitness, body composition, or your health in general, we would love to work with you! Please schedule a free 30 minute consultation to further discuss our programs and see which one best suits your needs.
