Just about everybody seems to be interested in weight control. Some of us weigh just the right amount, others need to gain a few pounds. Most of us “battle the bulge” at some time in our life. Whatever our goals, we should understand and take advantage of the important role of exercise in keeping our weight under control. Carrying around too much body fat is a major nuisance. Yet excess body fat is common in modern-day living few of today’s occupations require vigorous physical activity, and much of our leisure time is spent in sedentary pursuits.
Recent estimates indicate that 34 million adults are considered obese (20 percent above desirable weight). Also, there has been an increase in body fat levels in children and youth over the past 20 years. After infancy and early childhood, the earlier the onset of obesity, the greater the likelihood of remaining obese. Excess body fat has been linked to such health problems as coronary heart disease, high blood pressure, osteoporosis, diabetes, arthritis and certain forms of cancer. Some evidence now exists showing that obesity has a negative effect on both health and longevity. Exercise is associated with the loss of body fat in both obese and normal weight persons. A regular program of exercise is an important component of any plan to help individuals lose, gain or maintain their weight.
Overweight or Overfat
Overweight and overfat do not always mean the same thing. Some people are quite muscular and weigh more than the average for their age and height. However, their body composition, the amount of fat versus lean body mass (muscle, bone, organs and tissue), is within a desirable range. This is true for many athletes. Others weigh an average amount yet carry around too much fat. In our society, however, overweight often implies overfat because excess weight is commonly distributed as excess fat. The addition of exercise to a weight control program helps control both body weight and body fat levels.
Concept of Energy Balance
Losing weight, gaining weight or maintaining your weight depends on the amount of calories you take in and use up during the day, otherwise referred to as energy balance. Learning how to balance energy intake (calories in food) with energy output (calories expended through physical activity) will help you achieve your desired weight although the underlying causes and the treatments of obesity are complex, the concept of energy balance is relatively simple. If you eat more calories than your body needs to perform your day’s activities, the extra calories are stored as fat. If you do not take in enough calories to meet your body’s energy needs, your body will go to the stored fat to make up the difference. (Exercise helps ensure that stored fat, rather than muscle tissue, is used to meet your energy needs.) If you eat just about the same amount of calories to meet your body’s energy needs, your weight will stay the same on the average, a person consumes between 800,000 and 900,000 calories each year! All too often, people who want to lose weight concentrate on counting calorie intake while neglecting calorie output. The most powerful formula is the combination of dietary modification with exercise. By increasing your daily physical activity and decreasing your caloric input you can lose excess weight in the most efficient and healthful way.
Each pound of fat your body stores represents 3,500 calories of unused energy. In order to lose one pound, you would have to create a calorie deficit of 3,500 calories by either taking in 3,500 less calories over a period of time than you need or doing 3,500 calories worth of exercise. It is recommended that no more than two pounds (7,000 calories) be lost per week for lasting weight loss. Adding 15 minutes of moderate exercise, say walking one mile, to your daily schedule will use up 100 extra calories per day. (Your body uses approximately 100 calories of energy to walk one mile, depending on your body weight.) Maintaining this schedule would result in an extra 700 calories per week used up, or a loss of about 10 pounds in one year, assuming your food intake stays the same. To look at energy balance another way, just one extra slice of bread or one extra soft drink a day or any other food that contains approximately 100 calories can add up to ten extra pounds in a year if the amount of physical activity you do does not increase.