Conservative treatments for obesity1’2

There is a growing consensus as to the characteristics of conservative treatments for obesity. We will begin by describing these characteristics without attempting a precise definition. Conservative treatments can be characterized in a negative sense as treatments other than surgery or adjunctive instruments such as gastric balloons, very-low-calorie diets, or pharmacotherapy. They can be characterized in a positive sense by the rate of weight loss that they produce: 1% of total body weight per week. Kilograms of weight lost per week is a more conventional measure rate of weight loss but one with two disadvantages. First, it fails to take into account the different weight-loss requirements of patients of differing initial body weights. Heavier persons can, and probably should, lose more weight than lighterpersons. Second, the use of weight loss per week as a measure makes it difficult to compare the weight losses of persons with widely varying initial weights. Using instead the measure of percentage of body weight lost has the advantage of permitting such comparisons, which are of value in the assessment of programs that treat different patient populations. The use of a percentage of total body weight lost as a measure of the rate of weight loss is simple and readily understandable. Thus, the weight loss of a modestly overweight women of 70 kg would be 0.7 kg/wk while that of a severely obese person of 140 kg would be 1.4 kg/wk. Conservative treatments for obesity can be characterized also in terms of the caloric deficitsthat they prescribe. Instead of prescribing a fixed number of calories or a particular caloricdeficit,however, conservative treatments are perhaps best characterized in terms of the percentage of the energy required to maintain the body weight of the individual. This value is ‘-50% of maintenance energy requirements and rarely, if ever, < 40% of these requirements. Defining caloric intake in terms of baseline values permits the individualization of treatment by adjusting caloric deficit to the needs of particular persons. Thus, someone whose energy requirement to maintain body weight is 2000 kcal/d will be reduced to a caloric intake of 1000 kcal with a deficit of 1000 kca!. A person with a maintenance energy requirement of 4000 kca! will be reduced to a caloric intake of 2000 kca!/d, leaving a deficit of 2000 kcal.