Guide To Diets

Want To Lose Weight? Exercise!

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.

Exercise–Get Moving

The smart person today is not deciding whether to exercise, but is choosing an enjoyable activity and incorporating it into his or her life three to five times a week. The best news is that even moderate exercise can be an important part of a more fit lifestyle. The old idea, “No pain, no gain” is out. You can and do benefit from a sensible, painless, moderate exercise program. In fact, real pain is an indication to stop. The possibility of injury is much less with a moderate exercise plan than with very intense exercise. You also will experience fewer aching muscles and will be more likely to continue the activity over a long period of time.

One of the most common goals of an exercise program is weight control or weight loss. Moderate exercise can play an important role in a weight loss plan. The key in weight loss efforts is to move more, not necessarily faster or harder. Very intense exercise periods cannot last very long or occur very often. It is usually recommended that a person take a day off between such workouts.

Mild to moderate exercise, on the other hand, does not require the days off and can be performed more frequently. After a few weeks or months, those who exercise to lose weight can work up to an hour a day of exercise, five to six days a week.

Those over age 35 or who have a health condition should work with their physician or exercise physiologist before starting an exercise program. The physician or exercise physiologist may limit exercise to cause heart rate to be just 20 to 30 beats above resting heart rate. A few months later the person may work up to 60 to 70 percent of maximum heart rate.

The table below illustrates the calories used by performing intense exercise three times a week. It also illustrates the greater number of calories used by performing moderate exercise six times a week. The net result over time would be more weight lost with the moderate exercise plan.

Regular mild to moderate exercise can help minimize loss of muscle in a weight loss program. Those who lose weight and remain sedentary lose substantial muscle tissue, not just fat.

Regular physical exercise helps offset the declining metabolic rate normally associated with aging. This decline is 2 percent per decade after age 30, or about 100 fewer calories burned each day by age 50. If a person doesn’t eat less or exercise more, this could cause a yearly weight gain of 10 pounds. Another part of aging is a change in body composition-more fat and less muscle. Those people who exercise regularly have a more favorable body composition with less fat.

People who exercise regularly have a greater bone density than those who do not exercise. To be most helpful, regular exercise should be started early in life to help maintain bone density.

Moderate exercise performed regularly improves fitness. Overall fitness includes flexibility, as well as strength of cardiovascular system and muscles. Stretches before and after exercise can help prevent sore muscles and can increase body flexibility. An exercise which uses large muscle movement performed continuously and rhythmically–such as walking, swimming or cycling–can improve the heart’s function and strengthen muscles. Calisthenics can help with muscle strength.

Motivation

A 1985 Gallup poll found that 54 percent of the 1,019 adults surveyed said they exercised. With all of the excitement over exercise it seems that everyone should be fit.

However, few American adults and children exercise enough. Although many Americans are trying to become fit, 80 to 90 percent of Americans did not meet the minimum requirement for cardiovascular exercise in 1985. The Public Health Service defines the minimum as three or more times per week at 60 percent or more of target heart rate for 20 minutes.

Exercise, like most self-improvement programs, is not easy to incorporate into a lifestyle. Over half of those who start an exercise program drop out within a year. Overweight people may have even more difficulty staying with an exercise program. If you haven’t been able to stick to an exercise program, you may want to consider doing a few extra things to keep motivated.

Find someone to exercise with. Knowing someone is counting on you to show up can help on days you do not feel like exercising. Exercise is much more pleasant with a companion.
Set goals! Set attainable goals. Frequent success helps keep the motivation level up. Specify exactly what you wish to accomplish and how. Set some short-term goals. For example, after visiting with your physician you could set an exercise goal of 15 minutes each day for four days a week. The second week may be 20 minutes exercise for five days a week, A long-range goal may be 60 minutes, five to six days a week after three months of exercising. After you decide what you want to accomplish with exercise, write down your goals. Periodically take out your goals and look at them. While writing goals, write your goal for today. Writing things down helps us make them a commitment.
Reward yourself. Make the reward contingent upon reaching a goal. If weight loss is a goal, food is not the best reward.
Find your best time of day for exercise and then schedule it on your daily calendar. By setting aside a specific time, exercise will eventually become a habit. Try to make it part of your routine by exercising at the same time each day.
Think positively. Tell yourself that you enjoy exercise rather than that exercise is boring. The mind starts believing what it hears over and over. You may want to read books and magazines about exercise to keep your enthusiasm high.
Ask for support from your family and friends. If your family and friends do not support your efforts, it will be much more difficult to keep it up.
If you are thinking of quitting, think back to your first workout. Repeat it and see how easy that first workout is now. You should be able to see how far you have progressed.
Add a little variety. If you always run or cycle the same old route, it may get boring after a while. Trying new routes may help keep up your interest.
Last but not least, consider some of the health benefits you get from exercising: lower blood pressure, increased levels of high-density lipoprotein (HDL), a stronger heart, more efficient lungs, improved muscle tone, less chance of osteoporosis, weight control, more efficient gastrointestinal system, stress control and reduction of chronic tiredness.

Prepared by Michael H. Bradshaw , Extension Specialist, Health and Safety

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