Like Kuntzleman (below), a brief for weight control through increased activity, rather than through dieting--and somewhat the fuller of the two. Katahn, director of the Vanderbilt Univ. Weight Management Program, was spurred on by findings that thin people move more than fat people, even if they have the same lifestyle; so his aim is to change the sedentary lifestyle of the obese person into a more active one. Indeed, he points out, fat people can eat less than thin ones and still gain weight, because fat tissue is less active metabolically than other tissue: basically, the fatter the body, the fewer calories needed for maintenance. Katahn's solution is to increase the daily energy expenditure by 200 calories (about 45 minutes of walking or equivalent activity); if more rapid weight loss is desired, then caloric restriction can be added in the form of a reasonable 1200-1500 calorie diet. He sets forth a sound, moderate activity program of warm-up and stretch followed by an aerobic component (with the emphasis on walking--which even the very obese can adapt to their needs); and explains how to upgrade the program as fitness improves. With staid but thorough nutrition advice, the customary tips on problem eating, and some interesting methods for figuring out metabolic rate, a well-conceived manual--more solidly grounded in the body's workings than Kuntzleman's faultless pep talk.