Exercise & Weight Loss Analysis

The rate of obesity in the United States increased dramatically between 1989 and 2009, according to the Centers for Disease Control and Prevention. Permanent weight loss is an elusive goal for many people because of a lack of understanding of the relationship between exercise and weight loss. In order to build and maintain a healthy body, you must understand how the body burns calories, how much exercise you need, and what types of exercises are the most effective. Consult with your doctor before beginning any exercise regimen.

Calories

Every time you eat, you take calories into your body. The body uses calories to meet its daily energy needs. If any calories are left unused, they are stored as fat. Your body uses calories every time you perform any physical activity -- it takes calories just to beat your heart and expand your lungs during breathing, for example. You lose weight when your body needs more calories than you have supplied it, forcing it to dip into your fat or muscle reserves to make up the calorie deficit.

Calorie Expenditure

Exercise burns calories at a rate that is determined by your body weight and the intensity of the exercise. If you weigh 154 pounds, the U.S. Department of Health and Human Services estimates that you burn about 280 calories an hour walking. You burn more if you weigh more than 154 pounds. Running at five miles per hour, equal to a pace of 12 minutes per mile, increases your calorie expenditure to 590 calories. Since you must burn 3,500 calories to lose a pound of fat, losing weight solely through exercise is not an easy process.

Spot Reduction

Many people focus on exercising particular body parts, because they believe that they can localize fat loss in these areas. This cannot be done, says Michael Carrera, Professor Emeritus of Health Sciences at Hunter College of the City University of New York. The body loses weight according to a predetermined genetic pattern. Men typically lose weight from the stomach first, while women typically lose weight around the hips. Sit-ups do not burn fat around the stomach any faster than push-ups.

Body Composition

Your absolute body weight is not as important as your body composition -- the ratio of muscle to fat in your body. A bodybuilder, for example, might be fit at a weight that is considered obese for the average person of the same height and frame. If you lose weight using an extreme low-calorie diet without exercise, your body may make up much of the calorie deficit using muscle reserves instead of fat reserves, leaving you with more fat, even at a lower weight. On the other hand, a reasonable diet combined with weight training can build muscle mass while raising your body's resting metabolism so that it burns more calories even when you are at rest, asserts the Mayo Clinic.

Diet and Exercise

The most effective weight loss plan includes both diet and exercise, according to the U.S. Department of Health and Human Services. Exercise should ideally include at least some weight training, in order to build muscle and raise your metabolism. The result is a lean, toned body with a reasonable percentage of body fat. If you are only a few pounds overweight to begin with, you may even find that your body weight remains unchanged while your body composition changes dramatically,