144 Category 1 continuing medical education credits. MKSAP IX does not have a separate section on obesity. Fortunately, MKSAP X (1994) will contain a small section.
How much one eats (and, to some extent, what one eats) is a major determinant of body weight. Therefore, food intake should play a central role in all weight-management efforts. The overall goal in obesity treatment is to obtain a negative energy balance, because this is the only way to lose weight and body fat (see box titled ''Energy Balance"). Negative energy balance is established by reducing energy intake (i.e., eating less), increasing energy expenditure (i.e., performing more physical activity), or preferably both. All individuals need to alter their eating and activity patterns to lose weight. Programs that promise results without dieting and physical activity will surely be ineffective over the long term. This section focuses on diet, followed by a section on physical activity.
It is commonly believed that the obese overeat, but studies have not been able to make this connection consistently. Although obese subjects often underreport energy intake and overestimate physical activity (Lichtman et al., 1992), one cannot assume that all individuals with weight problems eat more than those of healthy weights. Energy requirements vary considerably among individuals, based on genetics, physiology, and metabolism, state of health, and, of course, factors such as level of physical activity, age, sex, body weight, and body composition. In experimental animals, genetically obese rodents have increased energy intake and decreased expenditure during development (Johnson et al., 1992). When obese rats (fafa) are pair-fed to their lean controls, weight gain is slower, but obese rats are still fatter than comparably fed lean rats (Cleary et al., 1980). At 6 months of age, obese rats (fafa) and lean rats have comparable energy intakes.
Although it is difficult to determine accurately an individual's food intake (from which the approximate energy and nutrient composition can be calculated), dietary assessment tools are available that can be self-administered or used by providers. These include diet histories, food records for varying lengths of time, repeated 24-hour recalls, food frequency questionnaires, and checklists. Many of these tools have been computerized for easy administration and more rapid interpretation. Appendix A discusses the major dietary assessment instruments used in obesity treatment.
A nutritionally adequate dietary pattern that provides all the essential nutrients and other important food constituents in the proper proportions and amounts is essential to good health. Today's dietary recommendations