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Cognitive factors in eating behavior in bulimia
Appetite, 1991, 17, 241
Cognitive
EMILY FOX MacLean Hospital (Harvard Medical School) and NORI
Factors in Eating Behavior
KALES (Speaker), G EARY (Rapporteur),
in Bulimia.
Columbia University.
Dr Fox Kales hopes to develop improved cognitive models of bulimia. In this Seminar she emphasized some methodological and theoretical difficulties she has encountered in this effort. The first study Dr Fox Kales described tested whether bulimics display the abstinence violation effect (AVE) in the laboratory. The AVE is the excessive intake which follows abrogation of restraint in restrained eaters. Here restraint was assessed with the EAT scale. Exceptionally unrestrained control subjects (mean EAT score, 6.5) were compared to 21 bulimics who both binged and purged at least once a day. Subjects consumed a 300-kcal chef salad lunch 3 h before the test. During the test they consumed a preload and were then offered a plate of Yodels chocolate snack rolls (“rolls”; 150 kca1/28 g roll). A mood and appetite questionnaire was completed before and after the preload and after the subjects ate the rolls. In the first test, preloads were 207 kcal of a food bulimics rated “safe”, grapefruit and oranges, or “forbidden”, ice cream. Control subjects ate about two rolls after both preloads, whereas bulimics ate significantly more rolls after ice cream (5.6) than after citrus fruit (3.0). Thus, the cognitive category of the preload is sufficient to elicit the AVE in bulimics. In a second test, preloads were 625-kcal chocolate ice cream shakes that were labeled either high calorie (HC; “contains cream, milk chocolate, sugar. . .“) or low calorie (LC; “contains skim milk, aspartame.. .“). Bulimics ate about twice as many rolis in the HC condition as in the LC condition, but the effect was not statistically significant. However, a large effect occurred in a subset of eight bulimic subjects who ate 10 rolls in the HC condition vs. only one in the LC condition. Dr Fox Kales suggested that these subjects may have believed the labels more than the other subjects. To circumvent this problem she plans to provide preloads in a nonrecognizable food form. Dr Kissileff suggested that the contribution of the preload’s perceived caloric value to the subject’s intake could be assessed by correlating intake and estimates of preload caloric content. Dr Fox Kales reported that this correlation was not significant. Dr Sunday made the interesting suggestion that mere anticipation of a HC preload might elicit an AVE. Dr Fox Kales hypothesized that the category of the preload (i.e., a forbidden vs. a safe food) may determine whether AVEs occur independent of the perceived or anticipated caloric value of the preload. The validity and utility of the concept of safe and forbidden foods also needs further investigation. For example, about 30% of the binges described by Dr Fox Kales’ subjects contained no forbidden foods at all. Dr Fox Kales next discussed the contribution of purging to bulimics’ eating behavior. Purging was not forbidden by the experimenters, and the subjects were allowed access to lavatories during testing. Subjects who reported purging after the test meals (11 of 21) ate many more rolls (12) than those who did not purge (2). Dr Fox Kales again emphasized the design subtleties of this work, noting that a decision not to purge may have overridden the AVE in some subjects. This possibility is suggested by the observation that subjects who said during debriefing that they were not prepared to purge in the laboratory generally ate no Yodels at all. Thus, perhaps only subjects who felt sufficiently comfortable to purge showed an AVE. Dr Geliebter suggested that it might be possible to manipulate this perception by differentially instructing the subjects about the option of purging. Dr Sunday suggested investigating the possibility that subjects might purge their test meals after leaving the laboratory. Dr Fox Kales ended with five conclusions: (I) Cognitive disinhibition models from restraint theory may be useful in the study of bulimia. (2) Bulimics’ purging behavior responds to preload manipulations. (3) The intention to purge may potentiate the AVE. (4) The AVE cannot be quantified by foods’ caloric content alone. (5) There may be clinical value in exposing bulimics to foods in environments where purging is prevented. Kales, E. F. (1990) Macronutrient
analysis of binge eating episodes in bulimia nervosa.
Physiology and Behavior, 48,837-840
Minutes for Columbia University Seminar on Appetitive Behavior, for 30 May 1991
Cognitive
EMILY FOX MacLean Hospital (Harvard Medical School) and NORI
Factors in Eating Behavior
KALES (Speaker), G EARY (Rapporteur),
in Bulimia.
Columbia University.
Dr Fox Kales hopes to develop improved cognitive models of bulimia. In this Seminar she emphasized some methodological and theoretical difficulties she has encountered in this effort. The first study Dr Fox Kales described tested whether bulimics display the abstinence violation effect (AVE) in the laboratory. The AVE is the excessive intake which follows abrogation of restraint in restrained eaters. Here restraint was assessed with the EAT scale. Exceptionally unrestrained control subjects (mean EAT score, 6.5) were compared to 21 bulimics who both binged and purged at least once a day. Subjects consumed a 300-kcal chef salad lunch 3 h before the test. During the test they consumed a preload and were then offered a plate of Yodels chocolate snack rolls (“rolls”; 150 kca1/28 g roll). A mood and appetite questionnaire was completed before and after the preload and after the subjects ate the rolls. In the first test, preloads were 207 kcal of a food bulimics rated “safe”, grapefruit and oranges, or “forbidden”, ice cream. Control subjects ate about two rolls after both preloads, whereas bulimics ate significantly more rolls after ice cream (5.6) than after citrus fruit (3.0). Thus, the cognitive category of the preload is sufficient to elicit the AVE in bulimics. In a second test, preloads were 625-kcal chocolate ice cream shakes that were labeled either high calorie (HC; “contains cream, milk chocolate, sugar. . .“) or low calorie (LC; “contains skim milk, aspartame.. .“). Bulimics ate about twice as many rolis in the HC condition as in the LC condition, but the effect was not statistically significant. However, a large effect occurred in a subset of eight bulimic subjects who ate 10 rolls in the HC condition vs. only one in the LC condition. Dr Fox Kales suggested that these subjects may have believed the labels more than the other subjects. To circumvent this problem she plans to provide preloads in a nonrecognizable food form. Dr Kissileff suggested that the contribution of the preload’s perceived caloric value to the subject’s intake could be assessed by correlating intake and estimates of preload caloric content. Dr Fox Kales reported that this correlation was not significant. Dr Sunday made the interesting suggestion that mere anticipation of a HC preload might elicit an AVE. Dr Fox Kales hypothesized that the category of the preload (i.e., a forbidden vs. a safe food) may determine whether AVEs occur independent of the perceived or anticipated caloric value of the preload. The validity and utility of the concept of safe and forbidden foods also needs further investigation. For example, about 30% of the binges described by Dr Fox Kales’ subjects contained no forbidden foods at all. Dr Fox Kales next discussed the contribution of purging to bulimics’ eating behavior. Purging was not forbidden by the experimenters, and the subjects were allowed access to lavatories during testing. Subjects who reported purging after the test meals (11 of 21) ate many more rolls (12) than those who did not purge (2). Dr Fox Kales again emphasized the design subtleties of this work, noting that a decision not to purge may have overridden the AVE in some subjects. This possibility is suggested by the observation that subjects who said during debriefing that they were not prepared to purge in the laboratory generally ate no Yodels at all. Thus, perhaps only subjects who felt sufficiently comfortable to purge showed an AVE. Dr Geliebter suggested that it might be possible to manipulate this perception by differentially instructing the subjects about the option of purging. Dr Sunday suggested investigating the possibility that subjects might purge their test meals after leaving the laboratory. Dr Fox Kales ended with five conclusions: (I) Cognitive disinhibition models from restraint theory may be useful in the study of bulimia. (2) Bulimics’ purging behavior responds to preload manipulations. (3) The intention to purge may potentiate the AVE. (4) The AVE cannot be quantified by foods’ caloric content alone. (5) There may be clinical value in exposing bulimics to foods in environments where purging is prevented. Kales, E. F. (1990) Macronutrient
analysis of binge eating episodes in bulimia nervosa.
Physiology and Behavior, 48,837-840
Minutes for Columbia University Seminar on Appetitive Behavior, for 30 May 1991