Everything you eat contains calories and everything you do uses calories, including breathing, sleeping, reading and digesting food. Controlling your body weight depends the balance between the number of calories you eat and use each day. When you eat more than you need to perform your daily activities, your body will store the extra calories and you gain weight. When you eat fewer calories than you use, your body uses the stored calories and you lose weight. When you eat the same number of calories as you use, your body weight stays the same.
Whether you are trying to lose weight or not, regular physical activity should be an integral part of your healthy lifestyle. In many ways, it doesn’t really matter what type of exercise you perform (providing that it is within your physical capability) – sports, gym sessions, household chores or work-based activities – all will burn calories.
There are basically SIX good reasons for incorporating exercise in a weight loss plan:
- Calorie Expenditure – a 30-min session of moderately intense aerobic exercise will burn around 300-400 calories. Even a brisk walk will burn around 200 calories. So exercising for just half an hour, every other day will help burn around an extra 1000 Calories a week. Since 1lb of fat contains 3,500 Calories then each month this type of exercise alone will help flight the flab!
- Increase in post-exercise metabolic rate – the longer the duration or the more intense the exercise, the longer your metabolic rate remains elevated after you’ve stopped and the more calories you burn. For example, after the 30-minute aerobic session, you probably burn another 100-150 calories during recovery.
- No loss of muscle tissue – the effect of a low-calorie diet without exercise is the loss of lean tissue, which is not good for your health and will result in a lowering of your metabolic rate. This is highly undesirable as it makes weight loss even harder! One study from the USA studied the contribution made by exercise in preserving muscle. This 8-week study on mildly obese adults showed that both the ‘diet only’ and the ‘diet + exercise’ (walk-jog/30mins/3xweek’) groups showed a similar total weight loss of around 9kg. However, the composition of the weight loss differed significantly. The ‘diet + exercise’ group lost virtually no lean muscle tissue, whilst the ‘diet only’ group lost on average around 3.5kgs of muscle. Also the ‘diet + exercise’ group lost far more fat (8.9kgs) than the ‘diet only’ group (5.5kgs). In other words, for the non-exercising subjects only around 60% of the total weight loss was fat loss compared to over 95% for the subjects who exercised.
The scientific explanation for this is that in response to regular exercise, the body produces more growth hormone, adrenaline and noradrenaline. These hormones activate an enzyme called ‘lipase’ which breaks down triglycerides (stored fat) into free fatty acids, which are then used as a fuel during aerobic exercise. Resistance exercises also stimulate the release of growth hormone, which can trigger protein synthesis and muscle growth. Hence exercise stimulates the fat burning processes and helps maintain healthy, well-toned muscles.
- Become a fat- burner instead of a fat-storer – a low-calorie diet without exercise will encourage your body to go into ‘fat-storing’ mode. If the brain senses that energy intake is too low, it stimulates the production of enzymes that will facilitate the storage of food energy more efficiently. This means that if you come off the diet, your weight will rapidly increase and may overshoot where you were before you started the diet. Regular exercise will stimulate the mitochondria in your muscles to develop fat-burning enzymes, so that you become better at burning fat calories.
- Exercise is a mild appetite suppressant – interestingly, rather than make you feel hungry, research shows that moderate aerobic exercise can actually make suppress your appetite – so a pre-lunch workout or walk can often be very helpful within your weight control plan.
- As you get fitter, you will be capable of burning more exercise calories – if you’re out-of-shape your tolerance to exercise will be low. For many, even a 30-minute brisk walk may be too far and a 30-minute aerobics class would be at a very easy level. For the unfit, the ability to burn calories is therefore very limited and a brisk walk may be at only 2mph. However, as you get fitter, your pace will increase and a brisk walk will now be at 4mph resulting in far more calories being burned every minute at the same moderate intensity of effort. You will also be able to exercise for longer. So getting in good shape not only makes you feel better but also enable your body to burn more calories during your work-out.
So, exercise not only helps control your weight but gives you more energy to carry out your daily lifestyle with vigour and alertness.