The Law of Metabolic Demand

The Law of Metabolic Demand, By Dr. Jade Teta — Your body likes to be either burning or building, not both. There are exceptions: beginners and those using steroids. This is the Law of Metabolic Demand. The body responds to what you subject it to. This is a major insight to the calorie argument. The idea that calorie excess always leads to fat gain and calorie reduction always leads to fat loss isn’t accurate. You can reduce calories and lose weight, but that weight may or may not be mostly body fat.
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The standard “eat less, exercise more” approach to dieting leads to about 20-50% loss of lean tissue (muscle). That’s important: metabolic rate accounts for over two-thirds of calories burned at rest and more than half of BMR is determined by your muscle mass. So you can be increasing calories and gaining weight, but that weight may or may not be fat. You could instead be gaining lean tissue – doing your metabolism a favor. The demands you place on your body will determine whether excess calories become fat or muscle and whether reductions in calories will result in fat or muscle loss. This is why weight training should be the dominant activity in fat loss plans. It’s the only type of movement that can funnel extra calories into muscle gain versus fat.
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One study looked at two groups of obese subjects put on identical very low calorie diets. One group was assigned an aerobic exercise protocol (walking, biking, or jogging 4 times per week). The other group was assigned resistance training 3 times per week and did no cardio. After 12 weeks, both groups lost weight. The cardio lost 37 pounds, 27 of which was fat and 10 of which was muscle. The resistance-training group lost 32 pounds, and 32 pounds were fat, 0 was muscle. When resting metabolic rate was calculated, the aerobic group was burning 210 fewer calories daily. In contrast, the weight-training group had increased their metabolism by 63 calories per day.