Chapter 9 – Weight Management
Chapter 9 Summary
The escalating epidemic of obesity results in thousands of preventable deaths each year. Many factors, including genetics, influence body weight, but excess energy intake and physical inactivity are the leading causes of overweight and obesity. Both underweight and overweight increase the risk of incurring various illnesses as well as various social and psychological stigmas.
A Closer Look at Obesity
The WHO considers obesity an epidemic with many contributing factors: genetics, large portion sizes, availability of energy-dense foods, sedentary lifestyles, and a built environment that fails to facilitate fitness.
Problems Associated with Weight
Underweight renders a person more vulnerable to physical stressors. Overweight increases risks of hypertension, heart disease and diabetes in those who are genetically predisposed, and has also been associated with gallbladder disease and breast cancer.
What Is a Healthful Weight?
To determine health risks associated with overweight and obesity, health professionals use three factors: body mass index, waist circumference and current health status. The latter may include heart disease, type 2 diabetes, high blood cholesterol, high blood pressure, cigarette smoking, osteoarthritis, gallstones, or sleep apnea. An initial goal for treatment of overweight and obese people with risk factors is to reduce body weight by about 10% at a rate of about 1 to 2 pounds per week. An overweight person who wants to lose weight needs to understand the concept of total energy needs as well as successful weight-loss strategies.
Energy Balance
Unhealthy weight results from an unbalanced energy budget (food energy in vs. energy expended on basal metabolism and activity). While the majority of energy used by the body fuels basal metabolism—accounting for 60%—the person’s physical activity level is important as well, and can help determine whether that person will have a healthy or unhealthy weight.
Causes of Obesity
In general, two schools of thought address the problem of obesity’s causes. One attributes it to inside-the-body causes (genetics, set-point theory, fat-cell theory); the other, to environmental factors (external cue theory). Eating behavior may be a response not only to hunger or appetite but also to complex human sensations such as yearning, craving, or compulsion. No doubt, the causes of obesity are complex and many causes may contribute to the problem in a single person. Given this complexity, it is obvious that there is no panacea for successful weight maintenance. The top priority should be prevention, but where prevention has failed, the treatment of obesity must involve a three-pronged approach, including adopting healthful eating habits, moderate levels of exercise, and behavior change.
Weight Gain and Loss
Weight change may be related to any of the body’s components, including fat and lean tissues, water and bone minerals. Excess energy is stored within the body as limited quantities of glycogen and virtually unlimited quantities of fat. During a fast, glycogen is soon exhausted, and then the body metabolizes fat plus muscle tissue, because the nervous system cannot use fat for fuel. If the fast continues, the body adapts by manufacturing ketone bodies, which the brain can use when glucose is unavailable.
Successful Weight-Loss Strategies
The problem with going on a rigid diet with a goal of, say, a 15-pound weight loss in 3 weeks is that it’s a quick fix—the dieter attempts to gain a temporary solution to what is typically a chronic problem. People are attracted to fad diets because of the dramatic weight loss that occurs within the first few days. Such people would be disillusioned if they realized that the major part of this weight loss is a loss of body protein, along with quantities of water and important minerals. A more healthful alternative is to develop habits gradually that you can live with permanently and that will help you shed pounds and keep them off over the long run. Instead of measuring your success by the needle on the scale, gauge your progress by the strides you make in adopting good eating and exercise habits as well as healthful attitudes about yourself and your body. Criteria for success are permanent changes in eating and exercise habits and maintenance of the goal weight over time.
Medications to assist obese persons with weight loss include, among others, Meridia, an appetite-suppressing drug, and Xenical, which reduces the body’s absorption of fat. Treatment of severe obesity includes medically supervised, very-low-calorie diets providing fewer than 800 calories or surgery on the stomach to reduce its volume.
Weight Gain Strategies
Healthful weight gain consist of building up muscle mass through weight training and increased calorie intake.
The Eating Disorders
The term eating disorder involves a wide spectrum of conditions, including anorexia nervosa, bulimia nervosa, and binge-eating disorder. Although the various conditions differ in their origin and consequences, they appear to have similarities among them—all of the conditions exhibit an excessive preoccupation with body weight, a fear of body fatness, and a distorted body image. Some researchers suspect that a complex interplay among environmental, social, and perhaps genetic factors triggers the development of eating disorders, mostly in women.