By Dr. Michael Colgan
Kristy came to my gym after spending a couple of years jogging with a local group, unsuccessfully trying to lose 15 pounds of stubborn fat off of her belly and butt. Her diet was very good; decent protein shakes, meat, fish, fresh veggies and fruit, good multi-vitamins/minerals, very little grains or dairy, low-glycemic, alkaline, and anti-inflammatory. She had read all our books. So the best I could give her was a resistance program, telling her she had to muscle up in order to slim down.
She wasn’t convinced, saying, “I don’t want muscle; where’s my cardio?” I told her if she wanted cardio as well she should take the dog for a walk, not waste her money paying me to jog uselessly on my treadmills. (Depending a bit on body type, percent body fat, age and effort, it takes 12 to 15 hours of treadmill jogging to remove one pound of fat.)
If you are trying to lose body fat, resistance exercise offers a huge advantage over aerobic exercise, such as jogging, even if you run 10-milers. Resistance exercise builds muscle. Aerobic exercise does not.
Just having more muscle increases your metabolic rate 24 hours a day, whether you are exercising or not. In science it’s called Resting Energy Expenditure. Your body uses more of its energy during the 4.7 hours per day that the average American watches TV, than during the hour or so you might spend at the gym.
How does it happen? Muscle and bone (and all other tissues) are constantly in a state of breakdown and renewal, replacing billions of cells every day. Removing each worn-out cell and replacing it with a new cell takes energy – lots of energy. Every year you replace about 15 percent of your entire body. The more muscle you have, the more you have to replace, and the more energy you use day and night, whether you move or not.
An average female athlete who comes to the Colgan Institute has about 33 kilograms (about 73 pounds) of muscle. Just to maintain itself, that muscle alone uses about 15 calories per kilogram per day, or 495 calories every day without moving at all. That’s twice the calories used in a one-hour jog.
We measured Kristy’s fat loss and muscle gain every month or so. She worked hard. In a year of three to four one-hour workouts per week she put on 3.4 kg (7.5 lbs.) of new muscle, a much higher than average muscle gain. She also lost 6 kg (13.2 lbs.) of fat, dropping to a lean 13 percent body fat.
Does not sound like a lot does it? But I have been doing exercise science for more than 50 years, and can tell you that most of the huge fat losses you see reported in the media are totally false. Sure, anyone can starve and dehydrate themselves for a few weeks and get big changes on the scale. But they are always temporary and unhealthy. We are in the health business, so the changes we get are at the pace the body replaces itself. It’s the only way that’s both healthy and permanent.
In terms of calories used per day, Kristy’s 3.4 kg of new muscle gives her a lean body insurance policy. Without moving it, the new muscle requires just over 52 calories every day simply to do its basic maintenance. That’s 365 calories each week, 19,000 calories every year.
That extra Resting Energy Expenditure effortlessly prevents a fat gain of 2.2 kg (approximately 5 lbs.) every year. In ten years it will prevent a fat gain of 22 kg (48.4 lbs.). Over the same 10 years, a girl of the same metabolic type as Kristy, who jogs for the same amount of exercise time will lose considerable muscle. The jogger’s Resting Energy Expenditure will fall, leaving her prey to the fat gain that’s always hiding around the corner just waiting for the chance to plump your pillows. Do the right resistance exercise and dodge the Plumper for life.
Reference: Wolfe RR. The underappreciated role of muscle in health and disease. Am J Clin Nutr. 2006 Sep;84(3):475-82.