Do Mass Gainers Make Your Metabolism Slower?

Mass gainers can help those struggling to add muscle mass.
i Siri Stafford/Lifesize/Getty Images

Mass gainers, also known as weight gainers, are high-calorie supplements that come in powdered form and are intended to help athletes outpace their metabolisms and gain muscle. While mass gainers typically help those with fast metabolisms by providing more calories than their bodies can burn quickly, the products do not actually slow metabolism. In fact, some ingredients in mass gainers may actually speed up your metabolism, or at least the speed at which your body metabolizes fat.

Typical Mass Gainer Profile

    While a mass gainer will provide an ample amount of protein -- perhaps 40 or 50 grams per serving -- these supplements differ greatly from simple protein powders. Mass gainers have added carbohydrates and fat, which help increase the calorie content dramatically. So while a protein powder might contain mostly protein and around 100 calories per serving, a mass gainer typically is mostly comprised of carbohydrates, and may offer 500, 800 or 1,000 calories per serving. Mass gainers may also contain added amino acids, creatine, or vitamins and minerals.


    Having a high protein content is one way in which mass gainers may actually speed up your metabolism rather than slow it down. As research from the May 2008 issue of "The American Journal of Clinical Nutrition" indicates, protein encourages more energy expenditure -- in other words, a more active metabolism -- than other nutrients. Because of this, high-protein diets may help promote an improved ratio of muscle to body fat.

Medium-Chain Trigylcerides

    Because fat is the most calorie-dense macronutrient, with 9 calories per gram, fats are a logical choice for high-calorie mass gainers. The supplements typically include mostly unsaturated fats, such as omega-3 fatty acids, which are considered beneficial for health. Mass gainers may also contain medium-chain triglycerides, a type of fat that may help boost your metabolic rate. Research from the November 2010 edition of "International Journal of Food Sciences and Nutrition" indicates these fats can help increase calorie burning and facilitate the burning of fat for energy.


    Carbohydrates are your body's primary source of energy, so mass gainers include plenty to fuel your workouts and to add calories. One type of carbohydrate mass gainers may include is fiber. Fiber helps provide feelings of fullness and assists in colon health. Additionally, research from the March 2008 issue of "The Journal of Nutrition" indicates fiber may help promote a healthy metabolism and promote a healthy body weight. Thus, fiber is another mass gainer ingredient that would not slow your metabolism and might actually do the opposite.

the nest