3.8: Summary

Our total energy need is the number of calories we take in when we aren’t gaining or losing weight. Since this number is elusive, we estimate our basal caloric need based on our body weight, gender, age, shape, and fatness. We add to this an estimated number of calories for physical activity, based on how active we are.

Obesity is defined in terms of Body Mass Index (BMI), calculated from height and weight. Obesity raises the risk of several diseases, as does excess abdominal fat in those who aren’t obese.

Anorexia Nervosa

Bulimia

False body perception—thinking "I'm too fat," even when emaciated; relentless pursuit of thinness Rigid dieting causing dramatic weight loss Rituals involving food, excessive exercise, and other aspects of life Maintenance of rigid control in lifestyle; security found in control and order Feeling of panic after a small weight gain; intense fear of gaining weight Feelings of purity, power, and superiority through maintenance of strict discipline and self-denial Preoccupation with food, its preparation, and observing another person eating Helplessness in the presence of food Lack of menses after the normal age of puberty

Secretive binge eating; never overeating in front of others Eating when depressed Binging followed by fasting, laxative abuse, self-induced vomiting, or excessive exercise Shame, embarrassment, deceit, and depression; low self-esteem and guilt (especially after a binge) Fluctuating weight resulting from alternate binging and fasting Loss of control; fear of not being able to stop eating Perfectionism, "people pleaser"; food as comfort/escape in carefully controlled and regulated life Erosion of teeth, swollen glands

Table 3-4: Anorexia Nervosa and Bulimia. Having some of these characteristics doesn’t diagnose the disease but should cause a person to reflect on their eating habits and related concerns.

Fatness clearly has a genetic component, but environmental influences also are a determining factor. Obese people are particularly responsive to outside signals that remind one of food or eating (e.g., finding it hard to walk by a bakery without stopping to get a tidbit). An important part of weight control can be to minimize exposure to those cues.

To lose fat, we have to eat less or burn more calories to tip the energy balance towards that goal. This, of course, isn’t so simple. There are deep-seated emotional reasons for eating, and the powerful pull of appetite makes it hard to tip the energy balance. For example, when we exercise more, we are usually hungrier. An important exception to this rule seems to be that the appetite of those who are sedentary and overweight doesn’t seem to fully compensate for a moderate increase in physical activity.

Other advantages of increased physical activity for weight control include increased lean body mass, which increases basic calorie needs, and possibly a lower “set-point” weight. Also, added exercise may be a way of dealing with stresses that might otherwise lead to over-eating. Increased physical activity can make a crucial difference in one’s ability to achieve significant and long-term weight loss.

The best reducing plan is one that includes at least moderate physical activity, a reduced-calorie diet that is nutritionally adequate, and behavior modification techniques to change eating and exercise habits so that long-term weight control is possible.

Anorexia Nervosa and Bulimia are eating disorders that take weight control to such extremes that health—and even life itself—can be in danger. Anorexics typically exercise compulsively and hardly eat, because they falsely see themselves as fat, even when they are dangerously emaciated. In contrast, bulimics mostly maintain their weight by inducing vomiting after eating huge amounts of food. These disorders should be diagnosed and treated as early as possible.