Macronutrient effects on satiety and binge eating in bulimia nervosa and binge eating disorder.

Women with bulimia nervosa (BN) and those with binge eating disorder (BED) have marked disturbances in satiety. For example, they consume greater food intake than controls throughout the day (Rossiter, Agras, Telch, & Bruce, 1992; Weltzin, Hsu, Pollice, & Kaye, 1991) and during binge eating episodes compared to controls asked to binge eat (Hadigan, Walsh, Devlin, LaChaussee, & 1992; Yanovski, Leet, Yanovski, Flood, Gold, Kissileff, & Walsh, 1992). In addition, women with BN report lower satiety after fixed meals than controls (Geracioti & Liddle, 1989). These findings are consistent with disturbances in physiological indices of satiety in these women, such as the blunted release of the satiety agent cholecystokinin following food intake (Geracioti & Liddle, 1989) and the increased gastric capacity (Geliebter, Melton, McCray, Gallagher, Gage, & Hash, 1992) found in women with BN. Another difference between women with BN or BED and controls is in their dietary selection. Women with these disorders have been found to consume lower proportions of protein during their binge episodes compared to controls asked to binge eat (Walsh, Kissileff, Cassidy, &, Dantzic, 1989; Yanovski et al., 1992). Women with BN also ingest lower proportions of protein during binges compared to their own non-binge episodes (Van der Ster Wallin, Noring, &, Holmgren, 1994), and in the overall diet compared to controls (Hetherington, Altemus, Nelson, Bernat, &, Gold, 1994). Women with BN begin binge episodes with dessert and snack foods, whereas controls begin binges with fish and meat (Hadigan, Kissileff, &, Walsh, 1989). These abnormalities in dietary selection may have particular significance in light of the different satiating effects of the macronutrients in normal individuals. Protein leads to greater suppression of food intake and greater reported fullness than other macronutrients (Latner & Schwartz, 1999). For example, 12 female college students without eating disorders were given three 450-kcal liquid lunches on non-consecutive days, high-protein (71%), highcarbohydrate (99%), and an equal mixture of these two liquid lunches, in counterbalanced order. Participants were asked to eat as much as they felt like at a buffet-style dinner 4 h later. They consumed 24% less at dinner after protein, and 17% less after the mixture, than after carbohydrate. Greater hunger and excitement about eating before dinner were reported in the carbohydrate lunch condition compared to the protein lunch condition. Greater enjoyment of dinner was reported in the carbohydrate condition compared to the mixture and protein conditions (Latner & Schwartz, 1999). Such short-term findings are consistent with reports that over the long-term, only dietary protein (as a proportion of total energy intake) is inversely correlated with later intake, unlike carbohydrate or fat (DeCastro, 1987). The satiety deficits in BN and BED might in part be corrected by inducing dietary patterns designed to increase satiety. It would be valuable to discover whether the different satiating effects of the three macronutrients also apply to individuals with eating disorders. The aim of the study was to compare the satiating effects of protein and carbohydrate in women with BN or BED. To examine this, 18 women (mean age 1⁄4 34.8) diagnosed with either BED (n 1⁄4 11; mean BMI 1⁄4 31.1) or BN (n 1⁄4 7; mean BMI 1⁄4 22.3) were given two 14-day periods of liquid supplements (280 kcal), high-protein (76%) or high-carbohydrate (96%) in a repeated-measures, counterbalanced design. Supplements were to be consumed three times each day, one hour prior to typical meal times. They were balanced