Exercise can make an important contribution to preventing or reversing obesity. In fact, it's essential in controlling or reducing body weight. Here are the 10 major reasons why exercise helps you lose weight:
Direct energy expenditure
Exercise helps with weight maintenance through direct energy expenditure (burning extra energy derived from body fat) and also improves aerobic fitness.
Mobilisation of body fat
Exercise mobilises body fat and increases fat oxidation. This means that when you exercise, the sluggish energy stores in body fat get put into use and burnt to release energy, thus reducing the amount of fat stored in the body.
Greater benefit for overweight people
Studies have shown that overweight people lose more body fat when they exercise than lean individuals. Thus exercise, especially of the aerobic type like cycling, jogging and brisk walking, has a more pronounced effect on those people who are obese and want to lose weight, than on people who are already thin.
Increases lean muscle tissue
Resistance exercise, such as gym workouts using apparatus and weight-lifting, increases lean body mass or muscle tissue, which has a higher energy turnover than fat tissue. By increasing the amount of lean muscle tissue in the body, the amount of energy you require to keep you body ticking over is also increased - a condition that promotes weight loss.
Counteracts energy-conserving measures
Exercise counteracts some of the self-protecting physiological responses to weight-reduction diets. When the human body is exposed to a reduced food intake on a low-calorie/kilojoule diet, a number of protective functions get activated to preserve the energy supply, for example processes that use up energy are reduced or switched off to conserve energy. If a low-calorie/kilojoule diet is combined with exercise, the body cannot go into the "switch-off mode", thus leading to weight loss.
Raises resting metabolic rate
Exercise stimulates the sympathetic part of the nervous system and raises the so-called resting metabolic rate (RMR). The RMR is the amount of energy your body needs to keep physiological progresses going (breathing, heart beat, digestion) when you're completely at rest. If the RMR is boosted, you use up more energy - even when you're resting - and start to lose weight.
Improves well-being and diet adherence
Exercise increases physiological well-being and improves adherence to diets. Studies have found that people on weight-reduction diets who combined their dieting with regular exercise felt healthier and stuck to their diets more easily than dieters who didn't do any exercise. So, if you're one of those people who have tried every type of diet known to mankind and failed to lose weight, the chances are that you didn't combine your dieting with an exercise programme.
Spontaneously increases general activity
Doing exercise on a regular basis results in a spontaneous increase in physical activity outside training hours, especially in men. This means that people who do regular exercise sessions actually start participating in more physically active pastimes in-between their sessions. It's logical that if you're more physically active all the time, you'll lose more weight.
Improves psychological well-being
Regular exercise also improves psychological well-being and prevents depression, which often goes hand in hand with weight loss. So to feel on top of the world even when you're dieting, do your exercise and beat the diet blues.
Promotes loss of centimetres
Finally, exercise helps you to lose centimetres, even if you don’t lose kilos. People who don’t diet to lose weight, but engage in strenuous exercise, often complain that they're not losing weight. The reason for this is that they are actually developing muscle tissue, which weighs more than fat tissue. If you embark on such an exercise-only programme of weight loss, then do take all your essential measurements before you start and check them once a week. You'll be surprised how many centimetres you'll lose, even if your weight does not initially decrease.
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Dr Ingrid van Heerden is a registered dietician and holds a doctoral degree in Nutrition and Biochemistry. She believes that "we are what we eat" and offers free nutrition and weight loss advice via her DietDoc service on Health24.com. Read more of her articles.