The effects of lisdexamfetamine dimesylate on eating behaviour and homeostatic, reward and cognitive processes in women with binge-eating symptoms: an experimental medicine study

Lisdexamfetamine dimesylate (LDX) is the only drug currently approved by the FDA for the treatment of Binge-Eating Disorder (BED), but little is known about the behavioural mechanisms that underpin the efficacy of LDX in treating BED. We examined the behavioural and neural effects of an acute dose of LDX (50 mg) in 22 women with binge-eating symptomatology using a randomised, crossover, double-blind, placebo-controlled experimental medicine design. LDX reduced self-reported appetite ratings and intake of both a pasta meal and a palatable cookie snack. LDX also decreased the eating rate of pasta but not of cookies and reduced self-reported liking ratings for pasta at the end of the meal. When viewing food pictures during an fMRI scan, LDX reduced activity bilaterally in the thalamus. LDX enhanced sustained attention and reduced impulsive responding in a continuous performance task but had no effect on emotional bias or working memory. These results suggest the observed effects of LDX on food intake (and by implication the efficacy of LDX in treating BED) may be related to the actions of the drug to enhance satiety, reduce food-related reward responding when full and/or increase cognitive control. Novel pharmacotherapies for BED might be most effective if they have a broad spectrum of effects on appetite, reward and cognition.

Emotional Responses to Food Pictures according to Caloric Value in Women with an Eating Disorder

Objective: The aim of the current study was to improve the understanding of emotions evoked by food pictures in women with an eating disorder (ED), by distinguishing anorexia nervosa (AN) and bulimia nervosa (BN) diagnoses, while taking into account the caloric content of food and the influence of participants’ nutritional knowledge. Methods: Thirteen AN, 9 BN and 22 healthy controls (HC) women participated in the study. In a laboratory setting, participants first completed self-report questionnaires regarding their affective state. Then, an emotional rating task of food and non-food pictures was performed in order to examine participants’ emotional reactions to these pictures, depending on the caloric value of the food depicted and controlling for internal state. Finally, an energy density ranking task of food pictures was completed to investigate participants’ nutritional knowledge and its influence on their reactions to food. Results: Compared to HC, ED participants experienced more fear towards food, which was neither due to their internal state nor to their nutritional knowledge. In AN, fear occurred towards all food, whereas in BN, fear was observed for high-calorie products only. Conclusion: The key role of food-induced fear in ED was highlighted, particularly in AN.

Food-Related Brain Activation Measured by fMRI in Adults with Prader–Willi Syndrome

(1) Background: Prader–Willi syndrome (PWS) is characterized by hyperphagia, resulting in morbid obesity if not controlled. The primary aim of this study was to investigate whether PWS patients show altered activation of brain areas involved in hunger. As a secondary objective, we assessed whether there is an association between these brain areas and several endocrine and metabolic factors in the fasting state. (2) Methods: 12 PWS adults and 14 healthy controls (siblings) performed a food-related experimental task after an overnight fast while brain activation in regions of interest was measured by functional MRI. (3) Results: In controls, significantly more activation was found in the left insula (p = 0.004) and the bilateral fusiform gyrus (p = 0.003 and 0.013) when the individuals were watching food as compared to non-food pictures, which was absent in PWS patients. Moreover, in PWS adults watching food versus non-food pictures a significant negative correlation for glucose and right amygdala activation (p_fwe = 0.007) as well as a positive correlation for leptin and right anterior hippocampus/amygdala activation (p_fwe = 0.028) was demonstrated. No significant associations for the other hormonal and metabolic factors were found. (4) Conclusions: PWS individuals show aberrant food-related brain activation in the fasting state. Leptin is associated with activation within the neural motivation/reward circuitry, while the opposite is true for glucose.

Food on the Move: The Impact of Implied Motion in Pictures on Food Perceptions through Anticipated Pleasure of Consumption

To tackle obesity, upgrading the image of healthy food is increasingly relevant. Rather than focusing on long-term benefits, an effective way to promote healthy food consumption through visual advertising is to increase its pleasure perception. We investigate whether implied motion, a popular trend in food pictures, affects food perceptions through anticipated consumption pleasure. Prior research shows that motion affects food perceptions, but these studies focused on limited food categories, using experiments with a single food stimulus, and mainly showing unhealthy food effects. Therefore, we aim to (1) replicate prior findings on the effects of food in motion on appeal, tastiness, healthiness, and freshness perceptions; (2) examine whether these effects differ for healthy and unhealthy food; and (3) investigate whether anticipated pleasure of consumption drives the effects of implied motion on food perceptions. Three between-subjects experiments (N = 626) reveal no evidence for the effectiveness of motion (vs. no motion) across a large variety of food products. We further show no differential effects for healthy versus unhealthy foods. Moreover, implied motion does not increase appeal or taste perceptions through anticipated pleasure. Considering the current replication crisis, these findings provide more nuanced insights into the effectiveness of motion in visual food advertising.

“I Know What I Like” – Indecisiveness Is Unrelated to Behavioral Indicators of Evaluation Difficulties

Indecisiveness, the subjective inability to make satisfying decisions, is an individual difference trait that may impede effective actions. Mechanisms underlying indecisiveness are largely unknown. In four studies, we tested the prediction that indicators of evaluation difficulty were associated with indecisiveness in simple evaluations. Across studies, indecisiveness was measured via self-report while evaluation difficulties were derived behaviorally from three indicators: difficulty distinguishing between similar evaluation objects (i.e., standard deviation of evaluation ratings), evaluation duration (reaction times), and implicit evaluations (evaluative priming effect) using familiar everyday objects. Study 1 (N = 151) was based on attractiveness evaluations of portraits. Studies 2a (N = 201) and 2b (N = 211) used chocolate as evaluation objects and manipulated to what extent the evaluations were equivalent to a decision. In Study 3 (N = 80) evaluations were measured implicitly through evaluative priming using food pictures. Contrary to our predictions, indecisiveness showed no reliable association to any indicator of evaluation difficulty, regardless of type of evaluation object, equivalence of evaluation and decision, and whether evaluation difficulty was based on explicit or implicit evaluations. All null findings were supported by Bayes factors. These counterintuitive results are a first step toward investigating evaluation processes as potential mechanisms underlying indecisiveness, showing that for both explicit and implicit measurements, indecisiveness is not characterized by difficulties when evaluating familiar everyday objects.

Take a Bite! The Effect of Bitten Food in Pictures on Product Attitudes, Purchase Intentions, and Willingness to Pay

Food pictures in advertisements, on packages, and on social media often display food with a bite in it. We investigated the effect of pictures of food with a bite (vs. no bite) on product attitudes, purchase intentions, and willingness to pay. In two online experimental studies we tested this effect for both pictures without context, as well as pictures in an advertisement. We also investigated two theories that could lead to opposite effects: consumer contamination and embodied mental simulation. We found that a picture of food with a bite (vs. no bite) resulted in lower purchase intentions, and that this effect was mediated by disgust (i.e., consumer contamination). Furthermore, we found an interaction effect of picture type (i.e., bite vs. no bite) and context (i.e., no context vs. advertisement) on purchase intentions: the effect of picture type on purchase intentions was attenuated when the picture appeared in an advertisement (vs. when the picture is shown without context). We found similar effects on product attitudes and willingness to pay. Lastly, a picture of food with a bite (vs. no bite) had no effect on embodied mental simulation. Field practitioners are advised to take caution when using pictures of bitten food as this may lead to unfavorable consumer responses because of a feeling if disgust.

Viewing images of foods evokes taste quality-specific activity in gustatory insular cortex

Previous studies have shown that the conceptual representation of food involves brain regions associated with taste perception. The specificity of this response, however, is unknown. Does viewing pictures of food produce a general, nonspecific response in taste-sensitive regions of the brain? Or is the response specific for how a particular food tastes? Building on recent findings that specific tastes can be decoded from taste-sensitive regions of insular cortex, we asked whether viewing pictures of foods associated with a specific taste (e.g., sweet, salty, and sour) can also be decoded from these same regions, and if so, are the patterns of neural activity elicited by the pictures and their associated tastes similar? Using ultrahigh-resolution functional magnetic resonance imaging at high magnetic field strength (7-Tesla), we were able to decode specific tastes delivered during scanning, as well as the specific taste category associated with food pictures within the dorsal mid-insula, a primary taste responsive region of brain. Thus, merely viewing food pictures triggers an automatic retrieval of specific taste quality information associated with the depicted foods, within gustatory cortex. However, the patterns of activity elicited by pictures and their associated tastes were unrelated, thus suggesting a clear neural distinction between inferred and directly experienced sensory events. These data show how higher-order inferences derived from stimuli in one modality (i.e., vision) can be represented in brain regions typically thought to represent only low-level information about a different modality (i.e., taste).

Face the food: Food plating with facial patterns influences appetite and event-related brain potentials

The presentation of visual food cues (e.g., food plating) can affect our appetite and leads to characteristic changes of early as well as late positivity in the electroencephalogram. The present event-related potential (ERP) study attempted to change ERPs and affective ratings for food pictures by rearranging the components of a depicted meal (conventional presentation) as a smiley or frowny. The images were presented to 68 women (mean age = 24 years), who rated the wanting and liking of the meals. Compared to conventional food plating, smiley and frowny meals elicited enhanced amplitudes of the P200, P300, and late positive potential (LPP) in a large occipito-parietal cluster. Frowny meals were rated as less appetizing than conventional food presentations. The mentioned ERP components are concomitants of face configuration processing (P200), automatic attention/novelty detection (P300), and voluntary attention/assignment of emotional meaning (LPP). Thus, the combination of two affective cues (food, face) in one stimulus changed the activation in motivational circuits of the brain. Also, serving a meal as a frowny could help to regulate appetite.