Re: The Heartbreakin' Rockstars #36, It is all about PROGRESS NOT Perfection
Why Not "Just Diet"?
One of the worst assaults on our bodies has been the self-imposed low-calorie diet. This has never seemed to be a very good idea, and recent research supports the notion that such diets can be harmful as well as ineffective.
The body’s survival response to low-calorie diets is to lower metabolic rate in order to burn fewer calories and minimize weight loss. One study of over-weight women on low-calorie diets found these women burned 350 fewer calories per day than when they were eating more normal amounts of food.
The slowed metabolic rate seen on very- low-calorie diets does not stop when a person begins to eat more normally. In fact, metabolism remains lower so weight maybe regained quickly. This, too, is a survival mechanism allowing rapid weight gain following starvation.
Unfortunately, all too many of us repeat this cycle of weight loss and weight gain. The long-term health effects are unknown, but animal studies suggest this yo-yo pattern makes each attempt to lose weight more difficult. With each diet cycle, weight is lost more slowly and regained more quickly.
Another problem with very-low-calorie diets is that weight loss is not all fat, but includes a substantial loss in lean mass, which includes muscle tissue. Exercise helps reduce this lean tissue loss. The combination of exercise and moderate calorie reduction is best for minimizing lean tissue loss during weight loss.
There are other health reasons to shy away from low-calorie diets if you are trying to lose weight. Recent research has linked very-low-calorie diets and the resulting overall low daily nutrient in-takes to the development of both coronary heart disease and osteoporosis in women. The reasons for this relationship are not known, but at this point it seems sensible to take a more moderate approach to cutting back on calories to lose weight.
Current recommendations for safe and effective weight loss from the American Dietetic Association suggest adults go no lower than 10 calories per pound of present body weight. For example, a 150-pound person should not eat fewer than 1,500 calories per day on a weight loss program; a 125-pound person no fewer than 1,250 calories per day. This is a change from the 1,200-calorie diet which is traditionally given to women wanting to lose weight. Using the 10-calories-per-pound guide will produce a gradual weight loss. Weight lost gradually is less likely to be gained back.
Why Exercise?
The reason we exercise is not just to burn those 100-plus calories for every mile we walk. Exercise does much more–it helps to increase our metabolic rate so we burn calories faster, Also, studies show that for a few hours following exercise, we continue to burn calories at a faster rate.
Exercise helps to prevent the body from moving towards the starvation or hibernation response. Many persons who go on a low-calorie diet cause their metabolism to be lowered and their body starts to conserve energy. Exercise will resist the body’s attempt to move into this condition.
Those who exercise usually gain muscle mass instead of losing it. Up to 20 percent of the weight lost by those who diet without exercise can be lean tissue. Those who increase exercise and while cutting calories usually gain a few pounds of lean tissue as they lose body fat. Lean tissue is needed to help metabolize fat. Those who diet without exercise lose lean tissue and therefore have less muscle tissue to metabolize fat.
Regular exercise has a positive effect on body chemistry. Studies show that muscle tissue from trained athletes contains more fat-burning enzymes than muscle from untrained individuals. Untrained subjects who participate in endurance-type exercise for several months develop an increased amount of fat-burning enzymes.
Most fat people have excessive insulin in their body tissues. An excess of insulin in body tissues, which is not used by the cells, can actually cause an increased storage of fat. Exercise helps the body’s cells to better utilize insulin, thereby reducing the need for more insulin.
All of the evidence is not in on exercise as a means of appetite control for humans. Some studies show obese people seem to experience an appetite suppression following moderate exercise, while other studies seem to contradict the findings. Appetite suppression following exercise may be psychological, but it certainly works for many.
Grant Gwinup, a researcher from the University of California campus in lrvine, studied obese men and women to see if exercise alone was effective in helping people lose weight.
Gwinup worked with a group of 34 obese men and women who were de-moralized after years of trying to lose weight. He told them to start a daily walking program and gradually work to increase their time and distance. The group accomplished nothing until they worked up to half an hour a day. Then they started losing weight and, at the end of the year, every one of the 11 patients who stuck with the program lost a significant amount of weight. The average weight loss was 22 pounds. The most successful lost 38 pounds, the least successful 10 pounds.
The ‘Hibernation’ Response
Scientists are discovering that people have the same ability to cope with a shortage of food as do small mammals. When there is a scarcity of food, some mammals conserve energy by slowing down their metabolism.
People, too, can adjust to less food, and chronic dieters seem best able to adjust to shortages. When the body is deprived of food, it adapts by causing the individual to conserve energy, store fat, and become tired. A person deprived of food usually becomes hungry, irritable, and even lethargic.
The process of severe calorie restriction runs counter to the dieter’s attempt to lose weight. Studies have shown that people on very-low-calorie diets do not reduce their ability to store fat. It now appears that extreme calorie restriction may even increase a dieter’s ability to store fat. Many persons who go on low-calorie diets stop losing weight after a few months. They stop dieting, return to normal food intake and quickly regain fat.
Richard Keesey, a psychologist at the University of Wisconsin, and his colleagues put rats on starvation diets until they reached 81 percent of their normal weight. The rats were then allowed to eat the same amount of food they and the control group ate prior to the diet. During a week of eating, the “starved” rats gained almost 20 times more weight than the control rats on a similar diet. The starvation diet had reset their metabolism rate so they burned fewer calories and stored a higher proportion of food as fat.
This may help to explain what happens to many dieters when they resume normal eating. Their body metabolism, which has changed to conserve energy, stores the excess calories as fat so it will be ready for future periods of starvation.
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10-31-2009, 09:12 PM
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