Chantal Nederkoorn

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.

Resisting temptation: Decreasing alcohol-related affect and drinking behavior by training response inhibition

According to dual-process models, excessive alcohol use emerges when response inhibition ability is insufficient to inhibit automatic impulses to drink alcohol. This study examined whether strengthening response inhibition for alcohol-related cues decreases alcohol intake. Fifty-two heavy drinking students were randomly assigned to one of two conditions: In the beer/no-go condition, participants performed a go/no-go task that consistently paired alcohol-related stimuli with a stopping response, to increase response inhibition for alcohol-related stimuli. In the beer/go condition, in contrast, participants were always required to respond to alcohol-related stimuli during the go/no-go task. Before and after the go/no-go manipulation, we measured weekly alcohol intake and implicit attitudes toward alcohol. In addition, we measured alcohol consumption during a taste test immediately after the go/no-go manipulation. Following the manipulation, participants in the beer/no-go condition demonstrated significantly increased negative implicit attitudes toward alcohol, and a significant reduction in weekly alcohol intake, while participants in the beer/go condition showed a non-significant increase in implicit positive attitudes toward alcohol and a significant increase in weekly alcohol intake. This study demonstrates that repeatedly stopping prepotent responses toward alcohol-related stimuli can be an effective strategy to reduce excessive alcohol use.

Cephalic phase responses, craving and food intake in normal subjects

Cephalic phase responses (CPRs) are elicited during exposure to food cues. They gear up the body to optimize digestion or they compensate for unwanted changes during a meal. The cue reactivity model of binge eating predicts that CPRs are experienced as craving for food, thereby increasing food intake and playing a role in abnormal eating behaviour. The present experiment was designed to measure CPRs in normal women and to examine its relationship with craving, food intake and restraint. Results show that normal subjects do react to food exposure with changes in heart rate, heart rate variability (HRV), salivation, blood pressure, skin conductance and gastric activity. These CPRs presumably gear up the body and presumably do not reflect compensatory responses. Significant correlations between restraint and blood pressure, between blood pressure and craving, and between craving and food intake were also found. These results are in line with the cue reactivity model and suggest that research into physiological CPRs and craving in the field of eating disorders is valuable.

The interaction between impulsivity and a varied food environment: its influence on food intake and overweight.

Objective:The current study tests the influence of two factors, the obesogenic environment and impulsivity, on food intake in primary school children. Our current food environment offers a large variety of cheap and easily available sweet and fatty foods. This obesogenic environment is believed to be a cause of the recent obesity epidemic. Impulsive people are generally less successful at inhibiting prepotent responses and they are reward sensitive. We investigate whether the interaction between an obesogenic environment and an impulsive person leads to overeating.Design:A quasi-experimental 2 (reward sensitive versus not reward sensitive) by 2 (successful response inhibitors versus unsuccessful response inhibitors) by 2 (monotonous versus varied food environment) between-subjects design with caloric intake during a taste test as the main dependent variable. The link between impulsivity and overweight was also examined.Subjects:78 healthy primary school children (age: 8–10 years).Measurements:We measured two aspects of impulsivity: reward sensitivity and deficient response inhibition. Subsequently, one aspect of the obesogenic environment was manipulated; half of the participants received monotonous food during a bogus taste test whereas the other half tasted food that was varied in colour, form, taste and texture.Results:As expected, reward sensitivity interacted with variety. In the monotony group there was no difference in food intake between the less and more reward-sensitive children (183 kcal±23 s.d. versus 180 kcal±21 s.d.). However, in the variety group the more reward-sensitive children ingested significantly more calories than the less reward-sensitive children (237 kcal±30 s.d. versus 141 kcal±19 s.d.). Reward sensitivity was not linked to overweight. Deficient response inhibition did not interact with variety, but it was linked to overweight.Conclusion:It is suggested that reward sensitivity could be a causal mechanism for overeating in an obesogenic environment whereas prepotent response inhibition may be a maintaining factor of the problem of overeating.

Experimental research on the relation between food price changes and food-purchasing patterns: a targeted review

One way in which to modify food purchases is to change prices through tax policy, subsidy policy, or both. We reviewed the growing body of experimental research conducted in the laboratory and in the field that investigates the following: the extent to which price changes influence purchases of targeted and nontargeted foods, total energy, or macronutrients purchased; the interaction of price changes with adjunctive interventions; and moderators of sensitivity to price changes. After a brief overview of economic principles and observational research that addresses these issues, we present a targeted review of experimental research. Experimental research suggests that price changes modify purchases of targeted foods, but research on the overall nutritional quality of purchases is mixed because of substitution effects. There is mixed support for combining price changes with adjunctive interventions, and there are no replicated findings on moderators to price sensitivity in experiments. Additional focused research is needed to better inform food policy development with the aim of improving eating behavior and preventing obesity.

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.

High-restrained eaters only overeat when they are also impulsive

Recent work shows that the inability to inhibit basic motor responses (like pressing a button) is related to overeating, weight gain and overweight. In the present study it was tested whether this inability to inhibit motor responses--or impulsivity--can differentiate between successful and unsuccessful restrained eaters. A typical preload and food exposure paradigm was used and it was hypothesized that only the high-restrained eaters that are simultaneously inefficient inhibitors of prepotent motor responses would overeat when confronted with tempting foods. In line with the hypothesis, the data show that overeating follows from an interaction between restraint and impulsivity; high-restrained eaters only overate when they were also impulsive. It is concluded that being restrained per se is not a determinant of overeating. Being a restrained eater only bears the risk of overeating in case of coexisting impulsivity.

Beer à no-go: learning to stop responding to alcohol cues reduces alcohol intake via reduced affective associations rather than increased response inhibition

AIMS   Previous research has shown that consistently not responding to alcohol-related stimuli in a go/no-go training procedure reduces drinking behaviour. This study aimed to examine further the mechanisms underlying this go/no-go training effect. DESIGN, SETTING AND PARTICIPANTS   Fifty-seven heavy drinkers were assigned randomly to two training conditions: in the beer/no-go condition, alcohol-related stimuli were always paired with a stopping response, while in the beer/go condition participants always responded to alcohol-related stimuli. Participants were tested individually in a laboratory at Maastricht University. MEASUREMENTS   Weekly alcohol intake, implicit attitudes towards beer, approach-avoidance action tendencies towards beer and response inhibition were measured before and after the training. FINDINGS   Results showed a significant reduction in both implicit attitudes (P = 0.03) and alcohol intake (P = 0.02) in the beer/no-go condition, but not in the beer/go condition. There were no significant training effects on action tendencies or response inhibition. CONCLUSIONS   Repeatedly stopping pre-potent responses towards alcohol-related stimuli reduces excessive alcohol use via a devaluation of alcohol-related stimuli rather than via increased inhibitory control over alcohol-related responses.