The philosophy of weight loss or weight management programs is to control the energy balance in the body. Food intake (not withstanding quality) must be balanced in relation to calorie expenditure. A complex interplay exists between energy intake and expenditure that involves genetics, environment, sleep, stress and exercise.
Food quality and quantity are very important to weight management, but I want to focus on the best ways to promote calorie expenditure, which is thought to have three major components. Resting metabolic rate is the amount of energy consumed just to keep us alive. When we exercise we can get around 30 per cent of our calorie burning from the exercise itself and resting metabolism contributes about 60 per cent. The remaining 10 per cent is energy required to absorb, digest and burn our food. If we do no exercise all day long, the resting metabolism contributes about 90 per cent of our calorie burning. And of this 90 per cent resting metabolism calorie burning potential, the majority comes from keeping our muscles alive – and our muscles make up roughly half of our body weight. So if we were to add muscle density, does that increase our resting metabolism and burn more calories, even as we sleep?
A 2004 study done in the International Journal of Obesity showed that a diet-only regimen tended to suppress resting metabolism up to 20 per cent, whereas adding aerobic and resistance training counteracted this effect. The authors suggest that without exercise, atrophy occurs but when you exercise you maintain or even increase muscle mass.
Of course exercise itself burns calories and in general the higher the intensity, the more calories you burn. The added benefit though is that higher intensity will contribute to muscle density as well. Very mild intensity will maintain muscle mass but may not increase it. But of course mild exercise is better than none at all, especially if it leads to more exercise down the road. And even though higher intensity is better, you should build up to that level after a period of time especially if you’ve been sedentary, have a medical condition or injury.
Another strategy that seems to be borne out in more recent research is the idea of eating smaller portions, more frequently throughout the day. Once again, on a calorie restricted diet with little or no exercise there may be a tendency to skip meals altogether. Besides creating potential inadequate nutrient intake and low blood glucose concerns, this strategy may be interpreted as a threat by the brain, resulting in a series of physiological reactions to conserve fat reserves on the body. Since the thermic effect of digesting food is about 10 per cent of the daily calorie burning it is postulated that more frequent eating will maintain this metabolic contribution even in the face of decreased food intake. And as far as the extra calorie burning of different foods, a 2010 study in the International Journal of Obesity found that there may be a small, brief effect from green tea, spices and caffeine, but very little research has been done on this area. There are many supplements and beverages out on the market that make similar claims, but good quality, independent research is still lacking.
So if your goal is weight loss, go about things sensibly and add exercise to your routine. You’ll be more successful, and you’ll feel stronger and have more energy.
• Kerry Senchyna holds a bachelor of science degree in kinesiology and is owner of West Coast Kinesiology in Maple Ridge.