Comportamento alimentar: efeito da privação no valor reforçador do alimento e as relações com o padrão alimentar de mulheres com diferentes índice de massa corporal

Abstract

Overweight has increased significantly in recent years. From a nutritional point of view, overweight treatment has as its central component deprivation and dietary restriction. Behavioral approaches have also been proposed offering strategies to aid weight loss. However, while these interventions have found short-term results, in the long term they do not appear to be effective. Previous studies have suggested that a better understanding of eating behavior is needed to propose long-term sustainable interventions. Considering eating as a multidetermined phenomenon, we proposed in Article 1 a definition of eating behavior and the effects of deprivation from the perspective of behavior analysis, based on Skinner's multi-causal model, composing a product of interactions between phylogenetic, ontogenetic and cultural factors. From this theoretical perspective, an empirical study was proposed that aimed to evaluate the effect of food deprivation on food choice and consumption. Sixty-two adult women with body mass index (BMI) between 18,6 and 43,7kg/m2 participated in this study. Participants were distributed in the condition of deprivation (Priv) or preload deprivation (PrivPL). Then a game was presented where participants could earn points for food or leisure and later were served a snack. Hunger perception was measured by the 100mm visual analog scale before being subjected to the experimental conditions (T0), after the condition and after the snack. All participants answered the Three Factor Eating Questionnaire (TFEQ-R21) and the Binge Eating Scale (BES) and were weighed and measured for BMI calculation. At the end the participants were asked about the diet practice (if they were dieting or if they were in the habit). All participants underwent all procedures and the results were analyzed in articles 2, 3 and 4. In article 2 the relationship between BMI, eating behavior and dietary practice was evaluated. This paper concluded that eating behavioral measures seem to change as a function of diet and/or BMI. Articles 3 and 4 have been proposed based on the literature that has suggested that food deprivation increases relative reinforcement value of food (RRVF), a measure of motivation for food choice, and that increased RRVF is also related to higher food intake. However, the literature suggests that RRVF should not be tested under conditions of deprivation and proposes the inclusion of a preload meal to evaluate it. Therefore, the objective of article 3 was to evaluate the effect of food deprivation (with and without preload) on RRVF, women's hunger reporting and food intake, and to evaluate the influence of BMI and diet practice on this relationship. As a result, in the Priv condition, food choice seems to be related to hunger perception, and BMI and diet also seem to influence hunger sensation. In article 4 it was evaluated whether the 9 dimensions of the TFEQ-R21 (uncontrolled eating, cognitive restriction and emotional eating) influence the effect of deprivation with and without preload on RRVF and women's food intake. The study points out that the dimensions of the TFEQ-R21 did not influence the RRVF for the PrivPC condition and the food intake was not influenced by either domain for either condition. This thesis was able to conclude that deprivation does not seem to be the best option to evaluate RRVF, however, this condition seemed to reflect the dietary condition. In addition, the variables BMI, diet practice and eating behavior should be taken into consideration in clinical practice as they influenced both the perception of hunger and the choice for food/leisure