Tuesday, February 26, 2008

Muscle Inferno: How many Calories is your lean mass actually burning?

If your answer is 30-50 extra Calories per pound of added muscle, you are ... dead wrong! This muscle myth is a wide-spread and detrimental piece of misinformation; extra muscle mass will improve health, improve functional strength, and make you sizzle, but the amount of muscle gained through resistance training in the short term will not send the metabolism soaring.
A top notch article (1: Best Pract Res Clin Gastroenterol. 2004 Dec;18(6):1009-29) reviewed the impact of various kinds of exercise on weight loss and metabolism, which was compiled for the American College of Sports Medicine (ACSM). To write this kind of paper, the authors searched extensively for the relevant scientific research about a topic and then combine all the results statistically to draw a conclusion.

The article states that 1 kg of muscle mass burns an additional 25-50 calories; the high estimate would tranlate to an additional 11.4 Calories per pound of lean muscle mass added. Consequently, this value is very similar to a value of 13 Calories/pound that I determined by statistically analyzing the data from my lab at Baylor University. The most conservative estimate predicts that an extra pound of muscle burns only about 7 Calories/pound.

A value of 30-50 kcal/lb of lean muscle is unrealistic and untrue, though it is published a lot in popular media. Numbers this high do not make practical sense. For instance, suppose a typical male bobybuilder has 100 lbs of muscle mass (not including the bone, organs and other components of fat-free mass), the mythical numbers would suggest that his muscle alone is burning between 3000-5000 Calories a day. On top of that, organs burn far more Calories per pound than muscle, so based on popular dogma, the man above maybe about 6000 Calories/day. I've measure the metabolism of countless athetic men, and roughly 3000 total Calories per day would be high for an athletic man of this size.

When high values are provided in articles, they are not supported by scientific literature; however, articles that reference research always suggest lower number, which generally range between 5-15 Calories per pound of muscle. Another good article that addresses this topic is below:

Jean offers nutrition coaching for weight loss, muscle gain, or any of your personal goals at her office in the Alico building in downtown Waco, TX right in the heart of central Texas. She also offers personal training services at Ironhorse gym on the corner of Franklin and 17th, which is also very convenient to downtown Waco. Contact information can be found on her personal website.


JC said...

really good post. I think its important to address these common silly misconceptions. Most people get their info from a magazine, so its nice to see some good sources now and then!

Jenna Williams, Phoenix, AZ said...

Thanks so much for posting true information, sources, and for addressing myths. As a personal trainer, I have heard things from my clients that make me want to hit my head on a wall because they are so far-fetched, unresearched, or just ridiculous. I address each one professionally, but it amazes me how often people will believe anything they hear without ever considering looking into it themselves. Great post!

Sildenafil said...

Calculate it properly is almost impossible, I i just do my work out, that's all.

Jean Gutierrez, PhD, RD said...

Thanks for your comments everyone! It's true that it's very hard to calculate your energy expenditure. But from my recent work in the metabolic chambers, it seems that resistance trained people burn more kcal/kg lean muscle mass than those who are untrained. Training not only increase total muscle mass, but may also improve capacity of a lb of muscle to burn more kcal at rest. It is certainly not as high as a lot of fitness mags will say. Thanks for your comments!