Weight Management: What is it?
Obesity and overweight are an epidemic in our country. According to the Dietary Guidelines for Americans, 2005, the prevalence of obesity in the United States has doubled in the past two decades1. Almost one third of adults are obese. And the prevalence of overweight children and adolescents has also increased substantially.
This high prevalence of obesity and overweight is a great public health concern. There are many specific health problems linked to overweight and obesity including type 2 diabetes, high blood pressure, high blood lipid levels, cardiovascular disease, stroke, gall bladder disease, gout, respiratory dysfunction, osteoarthritis and certain kinds of cancer. Obesity can lead to an inactive lifestyle because physical activity can be more difficult for an obese person. This inactivity can lead to additional weight gain. There are multiple factors that contribute to the complex health issues of overweight and obesity.
Overweight and obesity result from an energy imbalance that occurs over time. This is usually a result of the combination of consuming too many calories and too little physical activity. It’s really a matter of mathematics. Weight gain occurs when the number of calories consumed is greater than the number of calories expended. Weight is lost when the number of calories consumed is less than those expended. Weight is maintained when the calories consumed are balanced with the calories expended.
Calories measure the energy stored in foods and the energy used by the body. We need enough calories daily to support the functions in the body. Keeping the heart, brain and other organs functioning requires energy. It takes energy for the body to digest food and to absorb, transport and store nutrients from the food. Daily tasks and physical activity require energy. Age, body size and composition and gender affect calorie needs.
The calorie content of foods and beverages varies considerably. Calories in foods and beverages come from the nutrients protein, fat and carbohydrate. Protein and carbohydrate each contain about 4 calories per gram and fat contains about 9 calories per gram. Alcohol contains 7 calories per gram. Alcohol and sugar are called empty calories because they provide calories without other essential nutrients.
One pound of body fat gained represents approximately 3500 calories that were consumed but not expended. If a person took in 500 calories a day more than were expended that would result in a one pound gain of body fat in one week (500 calories times 7 days equals 3500 calories). To lose one pound of body fat one would expend or burn 3500 calories more than consumed.
This is a very simple equation but not always so easy to implement for a number of reasons. One is that people often develop habits that cause overeating and sedentary patterns. They simply regularly consume more calories than they expend and the result is weight gain. Habits are developed over time and aren’t usually quickly changed. But over time and with practice more healthful eating and exercise habits can be developed.
Achieving and maintaining a healthful weight is really about balancing the calories provided by the food and beverages consumed with the calories expended during the day.