Transforming food into fat seems all too easy for most of us. Losing fat is far more difficult, and to accomplish this we have only three alternatives:
1. Decrease food intake and keep activity constant, 2. Increase activity and keep food intake constant, or 3. Combine both approaches – diet and exercise.
Many of us become professional dieters. Year after year, we peel off pounds with the current fad diet – only to put the weight back on after reaching our goal and return to the habits that made us fat in the first place. But we can’t blame our fat on food. In one study of the causes of obesity, researchers found that only 3.2 percent of obese people became fat because of increased food intake. In 67.5 percent of the cases, inactivity was associated with the onset of obesity.
Physical activity can help reverse the results of inactivity. An hour of vigorous exercise burns up 300 to 600 calories. If you also cut 300 to 500 calories from your daily menu, you can lose weight at the rate of one to two pounds a week. Without exercise, you’d have to eat 500 to 1,000 fewer calories a day to lose the same number of pounds in a week. Exercise is not for everyone who’s overweight, however. The severely obese person should exercise only under medical supervision to prevent strain on the cardiovascular system and connective tissue. And no one should restrict food intake drastically without consulting a doctor.
How can you know if you need to lose fat? The best way is by finding out what percentage of your total body mass is fatty tissue. Be wary of the insurance tables that provide ideal weights for men and women of various heights. Rarely do these tables take body types or age into account. A six-foot man with a light skeletal frame could be thirty to forty pounds overweight at 200 pounds; a more muscular man with a heavy skeleton could be at his ideal weight. Weight tables sometimes allow slight increases with increasing age. This is misleading and wrong. Unless you’ve built up more lean muscle mass through exercise, you should weigh less, not more, as you get older.
When you think of fighting fat with exercise, you probably think of hours of hard, sweaty exertion. In man workout programs, participants never work at more than 60 percent of their capacity, and the exercise sessions lasts for only an hour. Yet the people not only lost fat during these workouts, but they kept losing fat for hours afterward – without moving a muscle or working up a sweat. How? During exercise they would raise their resting metabolism – one of the functions that burns up calories – by 7.5 to 28 percent. The higher rate persists for at least six hours after exercise. In the course of a year, this post-workout boost in caloric consumption could lead to a loss of four to five pounds – over and above the fat lost during exercise.
If exercise speeds up metabolism, doesn’t it also stimulate the appetite? Will you eat more as you exercise more, canceling out the benefits of your workouts? The answer is No! Appetite does not increase in proportion to moderate activity. Your hunger will increase only if you exercise for more than an hour a day, a period longer than is recommended for persons over 50. In laboratory studies, appetite decreased in previously sedentary animals when they were exercised for half an hour to an hour each day.
Studies also show that when you eat might be as important as what you eat. Rats trained to eat their entire daily ration in one to two hours gained more weight than rats who nibbled at their food whenever they were hungry. Eating just one giant meal increased the rate at which food is converted into fat by twenty-five times.
Some people are discouraged from exercising to lose fat because they think they have to work off 3,500 calories in one marathon effort. The metabolic equation of 3,500 calories per pound does not dictate the rate at which weight can be gained or lost. You’re far better off trying to lose fat a little at a time by adding pleasurable activities to your schedule. Just an extra half-hour of walking, for example, can burn off five pounds a year. Try to think in terms of the long haul and develop eating and exercise habits that can keep you in shape for months, years, and decades to come.