Patricia Thompson - NUTRITION TALK DIET AND exercise go together like love and marriage. Yet, two people in love are not necessarily compatible nor does it guarantee a successful marriage. This takes a lot of work and adjustment. To become complacent and start taking each other for granted is the gateway to breakdown in any relationship. So it is with diet and exercise. The two must work together with frequent changes and adjustments according to differing circumstances.
FUELLING EXERCISE
Just as a car needs a regular supply of fuel to reach the engine, so the body muscles require a regular supply of energy from food to function optimally. Muscles store their own fuel primarily as the carbohydrate, glycogen along with a little fat. This store can support vigorous exercise for up to about two hours. If refuelling is not done properly the muscles will become fatigued. This means providing carbohydrate before and after exercise and even during prolonged exercise and competitive sports.
The common practice of exercising without having eaten for several hours may cause many persons to feel dizzy. Muscles with low carbohydrate stores will draw sugar from the blood, thus depriving the brain of its prime source of fuel since nervous tissue cannot utilise fat. Ideally, your last meal before exercise should be no longer than 4-5 hours. If more time than this has elapsed, you should have a fruit or two to provide enough carbohydrate to maintain your blood sugar levels for the exercise bout. Drinking water is also needed to avoid dehydration.
WEIGHT LOSS AND EXERCISE
Many persons undertake exercise in the expectation of losing weight. They expect to see immediate results and, if this does not happen, they will give up too soon. The preferred source of energy for the muscle is carbohydrate and it takes time for the body to shift to burning fat. It is a trained muscle that will burn fat preferentially.
In the initial stages of beginning to exercise, your fitness level would not be high enough for you to be a fat burner. You must allow enough time of say four to six weeks to build up your fitness level before you can expect to start burning fat through exercise. Also, an exercise bout must be continuous at a moderate pace over an extended period and not just short bursts of vigorous exercise which favour carbohydrate.
Moreover, weight loss will only occur if the total daily energy output exceeds the total energy intake and over a period of time. If you increase your caloric intake by taking a drink of 300 calories after exercise that has only expended say 250 calories, you will not lose weight. Rather, you will gain five pounds or more if this is done consistently for one year.
Energy deficit occurs most readily with a reduced intake of food and results in a faster rate of weight loss than from exercise alone. However, quick weight loss, causes a lowering of the basal metabolic rate so that weight is easily regained. This is where the marriage with exercise is beneficial. Exercise maintains muscle tissue and raises metabolic rate so that weight loss can be maintained.
To reap the benefits of exercise, proper eating habits are essential and vice versa. There is no single diet or single type of exercise programme to suit all persons. As you progress through the different stages of life or fitness levels, your exercise and dietary needs and desires will also change. A continual process of adjustment is required for both your dietary and exercise programme to maintain harmony.
Patricia Thompson M.Sc., Registered Nutritionist, The Nutrition Centre, Eden Gardens.
