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Medicine LibreTexts

7: Energy Balance and Healthy Weight

Here, we take a look at the obesity epidemic and eating disorders—the extremes of energy imbalance—and we look at evidence-based recommendations for maintaining a healthy weight. You will learn how to assess body weight and fatness and learn that it is not only society and environment that play a role in body weight and fatness, but also physiology, genetics, and behavior—and that all of them interact. We will also discuss the health risks of being underweight and overweight, learn evidence-based solutions to maintain body weight at the individual level, and assess the current state of affairs of combating the obesity epidemic in the United States.

  • 9.1: Prelude to Energy Balance and Body Weight
    In this chapter you will learn how to assess body weight and fatness. You will also learn that it is not only society and environment that play a role in body weight and fatness, but also physiology, genetics, and behavior—and that all of them interact. We will also discuss the health risks of being underweight and overweight, learn evidence-based solutions to maintain body weight at the individual level, and assess the current state of affairs of combating the obesity epidemic in the US.
  • 9.2: Indicators of Health: Body Mass Index, Body Fat Content, and Fat Distribution
    Most people who are overweight also have excessive body fat and therefore body weight is an indicator of obesity in much of the population. To standardize the “ideal” body weight and relate it to health, scientists have devised some computational measurements to better define a healthy ideal weight. Body weight in relation to height is called BMI and is correlated with disease risk. Total body fat mass is another predictor of disease risk; another is where the fat is distributed.
  • 9.3: Balancing Energy Input with Energy Output
    Energy balance is achieved when energy intake is equal to energy expended and is essential for maintaining weight. Knowing the number of calories you need each day is a useful reference point, but it is also important to obtain your calories from nutrient-dense foods and consume the macronutrients. The amount of energy you expend includes not only the calories you burn during physical activity, but also the calories you burn at rest (basal metabolism), and the calories when you digest food.
  • 9.4: Too Little or Too Much Weight?
    The number of overweight and obese people in the world has now surpassed the number that is starving. As BMIs increase over 25, the risks increase for heart disease, Type 2 diabetes, hypertension, endometrial cancer, breast cancer, colon cancer, stroke, osteoarthritis, liver disease, gallbladder disorders, and hormonal disorders. Being underweight is linked to nutritional deficiencies that cause iron-deficiency anemia and delayed wound healing, and hormonal abnormalities.
  • 9.5: Dietary, Behavioral, and Physical Activity Recommendations for Weight Management
    Successful weight loss is defined as when individuals intentionally lose at least 10 percent of their body weight and keep it off for at least one year. Although there is a great variety of approaches to achieve successful weight loss most report that it involves adhering to a low-calorie, low-fat diet and doing high levels of activity (about one hour of exercise per day). The 2010 Dietary Guidelines for Americans recommendations are based upon scientific evidence.
  • 9.E: Energy Balance and Body Weight (Exercises)