Anne Roefs

Impulsivity in obese women

In our obesogenic environment, self-control might be necessary in order to prevent overeating. Impulsivity is supposed to make it more difficult to resist the temptation to eat too much and can thereby contribute to overweight. In the present study, the hypotheses is tested that obese individuals are more impulsive. Thirty-one obese and 28 lean women, sampled from the normal population, are tested on a behavioural measure and three self-report measures of impulsivity. The obese women appeared more impulsive on the last part of the behavioural task, but not on the self-report measures. Implications of the results are discussed.

Overweight children overeat after exposure to food cues

Overweight is becoming more common in children, but we know nearly nothing about the eating behavior of overweight children. Learning theory predicts that overeating follows from learned associations between the smell and taste of palatable food on the one hand and intake on the other hand. It was tested whether overweight children overeat after confrontation to these cues. They indeed failed to regulate food intake after both the exposure to the intense smell of tasty food (without eating it) and after eating a small preload of appetizing food, whereas normal-weight children decreased their intake after both cues. Overweight children are thus more vulnerable to triggers of overeating. Their overeating was not related to psychological factors like mood, body esteem, and a restrained eating style, but it was related to cue-elicited salivation flow. Apart from supporting the cue reactivity model of overeating, the data point to an interesting satiety phenomenon in normal eaters after prolonged and intense smelling palatable food without eating it.

Control yourself or just eat what you like? Weight gain over a year is predicted by an interactive effect of response inhibition and implicit preference for snack foods.

OBJECTIVE Previous research showed a strong relation between response inhibition, overeating and overweight. It was shown that people with ineffective response inhibition are more susceptible to the temptations of palatable food, eat more and are more often overweight or obese. In addition the results of several studies suggest that what needs to be inhibited may be an affect-driven motivation for food. In the present longitudinal study, we therefore investigated the interplay of response inhibition and implicit preferences for snack foods in predicting weight gain. DESIGN In a sample of predominantly normal weight undergraduate female students, implicit preference for food, response inhibition, and body mass index (BMI) were measured. After 1 year, BMI was measured again. MAIN OUTCOME MEASURES Weight gain of the participants over a 1-year period. RESULTS AND CONCLUSIONS The results strongly confirmed our expectations: participants with strong implicit preferences for snack foods and low inhibitory capacity gained the most weight. These findings imply that ineffective response inhibition may render people vulnerable to excessive or impulsive behavior in general, but that the manifestation thereof is determined by domain-specific preferences or needs.

The interactive effect of hunger and impulsivity on food intake and purchase in a virtual supermarket

Objective:It has been shown repeatedly that impulsivity, obesity and food intake are related; obese people are more impulsive than lean people and impulsive people eat more than less impulsive people. The relation between impulsivity and food intake might be state dependent; hunger motivates food seeking behaviour and food consumption, especially of high caloric food. Difficulties to overrule automatic behavioural tendencies might make impulsive people more susceptible to the effects of hunger on food selection. Therefore, they are expected to increase their intake more than low impulsive people when feeling hungry.Study 1:Fifty-seven female participants were randomly assigned to a hunger or sated condition. Response inhibition (a measure of impulsivity) and food intake were measured. Results show that impulsive participants ate significantly more, but only when feeling hungry.Study 2:Ninety-four undergraduate students participated. Hunger, response inhibition and the purchase of food in a virtual supermarket were measured. The same interaction was found: impulsive participants bought most calories, especially from snack food, but only when feeling hungry.Conclusion:Hunger and impulsivity interact in their influence on consumption. These data suggest that reducing hunger during calorie restricting diets is important for successful weight loss, particularly for the impulsive dieters.

External eating, impulsivity and attentional bias to food cues

Cognitive and behavioural responses to food reward, such as attentional biases and overeating, have been associated with individual differences in reward-responsiveness and impulsivity. This study investigated relationships between external eating, impulsivity and attentional bias to food cues, assessed using the pictorial visual-probe task. As previously reported, attentional bias correlated positively with external eating. Additional novel findings were: (i) attentional bias for food cues was positively related to trait impulsivity, (ii) attentional bias remained related to attention impulsivity after controlling for external eating. Our findings highlight the relationship between the ability to control impulsive responding and selective attention to food cues.

Fighting food temptations: The modulating effects of short-term cognitive reappraisal, suppression and up-regulation on mesocorticolimbic activity related to appetitive motivation

The premise of cognitive therapy is that one can overcome the irresistible temptation of highly palatable foods by actively restructuring the way one thinks about food. Testing this idea, participants in the present study were instructed to passively view foods, up-regulate food palatability thoughts, apply cognitive reappraisal (e.g., thinking about health consequences), or suppress food palatability thoughts and cravings. We examined whether these strategies affect self-reported food craving and mesocorticolimbic activity as assessed by functional magnetic resonance imaging. It was hypothesized that cognitive reappraisal would most effectively inhibit the mesocorticolimbic activity and associated food craving as compared to suppression. In addition, it was hypothesized that suppression would lead to more prefrontal cortex activity, reflecting the use of more control resources, as compared to cognitive reappraisal. Self-report results indicated that up-regulation increased food craving compared to the other two conditions, but that there was no difference in craving between the suppression and cognitive reappraisal strategy. Corroborating self-report results, the neuroimaging results showed that up-regulation increased activity in important regions of the mesocorticolimbic circuitry, including the ventral tegmental area, ventral striatum, operculum, posterior insular gyrus, medial orbitofrontal cortex and ventromedial prefrontal cortex. Contrary to our hypothesis, suppression more effectively decreased activity in the core of the mesocorticolimbic circuitry (i.e., ventral tegmental area and ventral striatum) compared to cognitive reappraisal. Overall, the results support the contention that appetitive motivation can be modulated by the application of short-term cognitive control strategies.

Food liking, food wanting, and sensory-specific satiety

Sensory-specific satiety refers to a temporary decline in pleasure derived from consuming a certain food in comparison to other unconsumed foods. It has been argued that such a reduction may not be limited to food liking but extends to food wanting as well. Animal research suggests that sensory-specific satiety reflects a reduction in both food liking and food wanting and in the present study it was investigated whether this also holds true for humans. Participants had to consume a certain amount of chocolate milk and afterwards approximately half of the participants played a game to obtain more chocolate milk, whereas the other half played a game to obtain crisps. Participants showed a decline in subjective liking of taste and smell of the chocolate milk in comparison to crisps. Furthermore, they showed less motivation (i.e. wanting) to obtain more chocolate milk. It is concluded that sensory-specific satiety in humans reflects a decrease in both food liking and food wanting.

At first sight: How do restrained eaters evaluate high-fat palatable foods?

Two experiments tested the hypothesis that restrained eaters display a greater liking for high-fat palatable foods, than do unrestrained eaters. This hypothesis was tested in the affective priming paradigm and in the extrinsic affective Simon task . Both paradigms were successful in uncovering food likes and dislikes, and both showed that participants were able to evaluate the palatability of foods relatively automatically. However, contrary to the hypothesis, food likes were not substantially affected by fat content, nor were they affected by restraint-status. Restrained and unrestrained eaters may like high-fat palatable foods to the same extent, but may differ in their craving for these foods.

Negative affect and cue-induced overeating in non-eating disordered obesity.

The recent separation of non-eating disordered obesity into a subtype that is high in negative affect and a subtype that is low in negative affect led to the hypothesis that the two subtypes would show opposite eating responses to typical triggers of overeating. Overweight/obese and normal weight participants, clustered into high and low negative affect subtypes, took part in an experiment using a control condition and two typically disinhibiting manipulations: negative mood induction and tasty food exposure. In accordance with the hypothesis, the negative mood induction and the food exposure elicited overeating in the overweight/obese high negative affect subtype. The overweight/obese low negative affect subtype did not eat more after negative mood induction and food exposure than without a trigger for overeating. Likewise, the normal weight participants did not show differential responses to the three manipulations. The increased vulnerability to overeating in this non-eating disordered overweight/obese subtype that is characterized by increased negative affect shows that individual differences play a crucial role in the way overweight/obese people handle temptations of the current environment. Being characterized by high negative affect makes it more difficult for the overweight/obese to resist temptations. Future studies into non-eating disordered obesity should consider the existence of these two subtypes.

Attentional bias for body and food in eating disorders: increased distraction, speeded detection, or both?

Previous research suggests that eating disorder patients show an attentional bias for body- and food-related information. However, so far little is known about the mechanisms that underlie the attentional favoring of this particular information in eating disorder patients. In the present study, we used both a body and a food visual search task to study speeded detection and increased distraction in eating disorder patients (n=67) and healthy controls (n=60). Compared with controls, eating disorder patients showed evidence of speeded detection of body-related information, and increased distraction by food information. These results suggest that the mechanism underlying the biased attentional allocation of eating disorder patients varies, and is dependent upon the type of information they are presented with.