关键词: 失败的限制性饮食者, 抑制控制训练, 不健康食物选择, 停止信号任务

Abstract:

Restrained eaters (REs) are highly focused on their weight and can be divided into successful and unsuccessful subgroups. The goal-conflict model proposes that restrained eaters have conflicting goals, enjoyment of food versus dietary restraint. When strength of the enjoyment goal surpasses that of the dietary restraint goal, people are viewed as unsuccessful restrained eaters. Unsuccessful REs are a high risk group for eating disorders and they have inhibitory control deficits compared to other people and are more likely to have eating behavior triggered when exposure to food environments and highly palatable food. Consequently, it is important to control their impulsive eating behaviors toward unhealthy foods. Previous studies have found that these impulsive behaviors can be controlled by the process of inhibition. In this research, unsuccessful REs were identified and engaged in a stop signal task to reduce their approach tendencies toward unhealthy food and change their explicit and implicit attitudes toward unhealthy food. From an initial sample of 310 Chinese undergraduate women, we recruited 66 unsuccessful restrained eaters based on scoring cut-offs from the Three Factor Eating Questionnaire and Dutch Eating Behavior Questionnaire. Unhealthy food frequency questionnaire, Food ratings (liking and attractiveness rate toward health and unhealthy food) and Single Category Implicit Association Test were used as baseline tests for all the participants. On the basis of random assignment, 33 women in the experimental condition engaged in inhibitory control training towards unhealthy food pictures) while 31 women in the control condition were provided with inhibitory control training towards non-food pictures). Each woman received seven 10-minute training sessions over one week. Finally, the participants completed a post-training assessment comprised of re-administered baseline measures and a food choice task. At baseline, self-reported weekly unhealthy food intake, food rating and implicit attitude towards unhealthy food did not differ between these two groups. Repeated MANOVA analyses, with group (intervention vs. control) and time (pre-training vs. post-training) as independent variables, were conducted to assess changes in self-reported weekly unhealthy food intake. The significant Group × Time interaction, (F(1,62) = 10.81, p < 0.01), indicated experimental group participants chose healthier food than control group in the food choice task. Experimental participants also had a reduction in reported liking and attractiveness of unhealthy foods between baseline and post-test compared with the control group. There were no changes in implicit attitudes towards unhealthy food in these two groups. As both groups showed an implicit preference for unhealthy foods both at baseline and post-intervention. In conclusion, these findings showed that inhibitory control training may be useful in addressing overt responses to unhealthy foods among unsuccessful REs though this intervention did not have a significant impact on implicit preferences for unhealthy food. In the future, researchers should further consider mechanisms underlying inhibitory control training.

Key words: unsuccessful restrained eaters, inhibitory control training, unhealthy food choice, stop signal task