How Does Weight Loss Happen?

Eating

The body's energy source is the food you eat. The calories from foods in the form of carbohydrates, proteins and fat fuel the activities of the body. Food and calories are necessary for normal body functions and for regular physical activity.

Activity

Each person has a set amount of energy or calories necessary to stay alive. The Basal Metabolic Rate (BMR) denotes the number of calories your body needs for basic function. This includes things such as respiration and breathing. The Resting Metabolic Rate (RMR) is the amount of calories your body consumes when it is at rest; perhaps when you are lying in bed or relaxing after a long day. Calories are also used when food is digested by the body. This is referred to as the Thermic Effect of Food (TEF). In addition to these factors, regular physical activity and movement use even more calories.

The number of calories needed for each person on a daily basis varies. It is dependant upon age, gender, weight, activity level and muscle mass versus fat mass. There is little you can do to influence the factors that determine calorie burn, with the exception of physical activity. Exercise can greatly increase caloric need, while a sedentary lifestyle can greatly reduce it. In addition, muscle is more efficient than fat mass for using calories.

The Balance of Eating and Activity

Weight loss can be reduced to a pretty simple equation. It is all about manipulating the controllable factors when it comes to the calories consumed through food and the calories burned through activity.

When you match the amount of calories you eat with the amount of calories your body is using each day, weight is maintained. It may fluctuate slightly, but there is no significant increase or decrease. Things are in balance. This can happen whether you are overweight or at a healthy weight. If the body is getting the right amount of calories to maintain the current activity level, weight will remain steady.

When you consume fewer calories than the body needs on a daily basis, weight loss occurs. While consuming less energy can be an important component for weight loss success, you can also increase calorie burn through exercise for the same result. Either way, there is a negative balance. The body gets less than it needs and begins to use energy stores in the body for fuel, which results in weight loss.

The opposite is also true. Excess caloric intake or a drastic decrease in activity level can mean the body is getting too many calories than it needs. This will lead to weight gain over time.

Resources

• Weight-control Information Network
• American Dietetic Association
• American College of Sports Medicine