Effects of preloads of differing energy and macronutrient content on eating behavior in bulimia nervosa

Evidence suggests that bulimics demonstrate blunted satiety possibly due to repeated episodes of overeating. This suggestion was tested further by comparing responses to yogurt preloads differing in carbohydrate and fat relative to a lower energy control yogurt in 12 bulimics and 12 age- and weight-matched controls. Participants were tested on three occasions at lunchtime. On each occasion, appetite and mood were rated before and after receiving a lunch of raspberry yogurt (350 g). Covert manipulation of energy and nutrient content was achieved by matching the yogurts on sensory properties and formulating a control yogurt (161 kcal), a high-fat version (357 kcal: 65% calories from fat), and a high-carbohydrate version (357 kcal: 81% calories from carbohydrate). Although there were no differential effects of the preloads on intake of an ad libitum test meal given 5 hr later in either the control or bulimic groups, there were significant differences in test meal energy intake between groups. On average and with all conditions combined, bulimics ate significantly fewer calories (775 +/- 167 kcal) than controls (1182 +/- 94 kcal) and consumed a greater percentage of calories from carbohydrate than controls. Bulimics restricted their intake relative to controls, and chose foods low in fat. This study provides further evidence of restricted eating in bulimia nervosa when the opportunity to purge is not available. Furthermore, the present study suggests that intake by bulimics is not influenced by nutrient content per se but by consideration of the caloric value of foods and the consequences of eating certain foods for weight control.