Oxygen helps you win in the body-shaping war

Press, 20 February 1986, Page 8

Oxygen helps you win in the body-shaping war

YOUR FOOD STYLE

JANICE BREMER

DIETITIAN

Diet clubs and diet doctors are now saying that overweight is not a function of eating too many calories or kilojoules but a dysfunction of not using up enough of them. Our metabolism is a legitimate scapegoat in our minds when we fail to keep to the rules of absurd diets. Metabolism is the process by which our bodies burn food to supply energy as kilojoules. The process requires oxygen. The more oxygen we breathe in, the more food kilojoules are used. Clearly, a sluggish metabolism, whether due to deliberately reducing food intake or to an inherited need for very little food, is not the only factor, in cases of overweight. Many people do eat more than even a regular metabolism can burn off. More vital to life than food, oxygen is the clue to beating a sluggish metabolism in the body shaping war. Training the body to take a greater load of oxygen is the answer to our kilojoule problems. Regular physical activity of an aerobic nature — that is, it requires quicker

breathing and a faster heart rate to deliver extra ' oxygen to the working , muscles — has a three- , fold effect in increasing the rate of matebolic ' activities:— , ® It builds muscle, which burns more kilojoules than fat. ® Kilojoules are used in the activity itself, as well as for some time after the activity. • Improved fitness increases the ability to take in oxygen and therefore to bum fat at a higher exercise intensity. (You need oxygen to bum fat and sustain exercise for a longer time. Energy derived without oxygen is only in short term sup- * Ply.) ’ Low intensity endur- < ance exercise therefore 1 uses more oxygen than 1

short, high Intensity exercise which has a high demand for the body’s carbohydrate stores, glycogen. This means that if you exercise so vigorously for say ten to fifteen minutes that you have to stop, all out of puff, to get your breathing in control glycogen has been used. Repeated doses of such activity in attempt to lose weight will cause hunger, and if this is ignored the body weight lost will include a considerable amount of muscle and water before fat is lost to any great extent. This is a similar effect to a low carbohydrate or very low kilojoule diet and like the diet cannot be kept up for long — hunger, fatigue and de-

pression eventually take over. Exercise of the right type increases metabolic rate as the body adjusts to • need more oxygen. Weight losing exercise Exercise that uses the large muscles of the body repeatedly in a steady rhythmical way, such as brisk walking, jogging, running, swimming or cycling are common aerobic activities. Certain types of dance classes that allow continuous exercise with reasonably even breathing are also popular. Exercise equipment at home can also be used if correctly executed. Walking and jogging can be started slowly without professional help if we are sensible about improving gradually. A fitness assessment and tailored exercise prescription is a good idea for those very overweight, unfit, or attempting the more adventurous types of activity. An exercise physiologist carries out such tests. For some years now trials studying the risk

factors for heart disease have been finding that those who eat fewest kilojoules (but are not lighter weight) are at greater risk than those eating at a more normal energy level. Inheritance and physical activity appear to be the differentiating factors. Only overweight people can put on several kilograms in a single week and then only after they have dieted. In my last column I gave the first clue to . beating a slow metabolism and body fat problem — control the rate of weight loss to no more than one kilgram per fortnight and do not crash diet. Clue two is: set aside time to undertake moderate and consistent exercise to control the rate of carbohydrate turnoverrather than using short extra-strenuous workouts. The chosen activity must be fun. It is time that “body watchers” and health seekers alike (in contrast to serious competitive athletes) let themselves play and enjoy rather than making exercise another obsession to replace dieting!