Eating less from bigger packs: Preventing the pack size effect with diet primes

Activation Versus Change as a Principle Underlying Intervention Strategies to Promote Health Behaviors

BACKGROUND AND PURPOSE

Interventions are effective in promoting health behavior change to the extent that (a) intervention strategies modify targets (i.e., mechanisms of action), and (b) modifying targets leads to changes in behavior. To complement taxonomies that characterize the variety of strategies used in behavioral interventions, we outline a new principle that specifies how strategies modify targets and thereby promote behavior change. We distinguish two dimensions of targets-value (positive vs. negative) and accessibility (activation level)-and show that intervention strategies operate either by altering the value of what people think, feel, or want (target change) or by heightening the accessibility of behavior-related thoughts, feelings, and goals (target activation).

METHODS AND RESULTS

We review strategies designed to promote target activation and find that nudges, cue-reminders, goal priming, the question-behavior effect, and if-then planning are each effective in generating health behavior change, and that their effectiveness accrues from heightened accessibility of relevant targets. We also identify several other strategies that may operate, at least in part, via target activation (e.g., self-monitoring, message framing, anticipated regret inductions, and habits).

CONCLUSIONS

The Activation Vs. Change Principle (AVCP) offers a theoretically grounded and parsimonious means of distinguishing among intervention strategies. By focusing on how strategies modify targets, the AVCP can aid interventionists in deciding which intervention strategies to deploy and how to combine different strategies in behavioral trials. We outline a research agenda that could serve to further enhance the design and delivery of interventions to promote target activation.

Snack Package Size and Variety Differentially Influence Energy Intake and Food Choices in Healthy Adults

BACKGROUND

While energy and nutritional content of snacks can contribute to overconsumption, other factors within the modern food environment may also influence the amount and types of snacks consumed.

OBJECTIVES

The aim was to examine whether snack package size and variety influence free-living snacking behavior in healthy adults. The impact of intuitive eating score on snacking behavior was also examined.

METHODS

Thirty adults [age: 23.6 ± 0.8 y; BMI (kg/m2): 22.8 ± 0.5] participated in a randomized crossover-design study. Participants were provided, in randomized order, with the following isocaloric snack exposures to consume for 3 d/exposure-1) CONTROL: highly appealing/appetizing snacks (e.g., dessert snacks, candy, savory snacks, fruits and vegetables, protein snacks); 2) LARGE-PACKAGE: similar snacks as CONTROL but in larger package sizes; and 3) VARIETY: larger variety of snacks. The primary outcomes included the 3-d average ad libitum snack energy, macronutrient content, and food choices for each snack exposure. The secondary outcome was the intuitive eating score and snacking behavior.

RESULTS

LARGE-PACKAGE increased snack intake by 11.9% (1150 ± 81 kcal) compared with CONTROL (1030 ± 71 kcal, P = 0.04), whereas VARIETY snack intake (1030 ± 69 kcal) was no different from CONTROL (P = 1.0). LARGE-PACKAGE increased consumption of desserts compared with CONTROL (P = 0.03) and VARIETY (P = 0.02). Alternately, VARIETY increased consumption of fruits and vegetables compared with LARGE-PACKAGE (P = 0.01) and CONTROL (P = 0.01). Intuitive eating score was not significantly associated with snack intake or snack choice (all, P > 0.05).

CONCLUSIONS

Snack package size and variety differentially influence energy intake and food choices in healthy adults. This trial was registered atclinicaltrials.gov (NCT03940105).

Examining the neural correlates of goal priming with the NeuroShop, a novel virtual reality fMRI paradigm

OBJECTIVE

Health goal priming has been shown to stimulate healthy food choices by activating an individual's weight-control goal. The present study combined fMRI with a novel virtual reality food choice task to elucidate the underlying neural mechanisms of health goal priming. Previous research has suggested that the ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC) play a role in the incorporation of health considerations into the food choice process. Responses may be more representative for those found in real life when assessed in an environment similar to the actual choice environment. Therefore, the first aim of the study was to explore if a novel virtual reality food choice task is sufficiently sensitive to detect basic valuation processes in food choice. The second aim was to examine whether increased activation in the dlPFC drives the effects of health goal priming.

METHODS

Fifty-six female participants performed an fMRI food choice task embedded in a virtual supermarket environment. They chose between perceived healthy and unhealthy products in a health prime, hedonic prime, and non-food control condition, while activation in brain areas involved in self-control and valuation (vmPFC, dlPFC) was assessed.

RESULTS

There were no differences in relative preference for perceived healthy products over unhealthy products between the conditions. There were also no main effects of prime condition on brain activation in the vmPFC and dPFC during food choice. Across conditions, activation in the vmPFC correlated with the tastiness of the chosen product during food choice.

CONCLUSIONS

Although the study does not provide support for health goal priming triggering neural self-control mechanisms, results did show that virtual reality has potential for a more realistic fMRI food choice paradigm.

The Effect of Downsizing Packages of Energy-Dense, Nutrient-Poor Snacks and Drinks on Consumption, Intentions, and Perceptions-A Scoping Review

The single-serve packaging of discretionary foods is becoming increasingly popular, but evidence is limited on whether smaller package sizes can reduce food intake. The aim of this scoping review is to assess the effect of reducing the package size of energy-dense, nutrient-poor (EDNP) snacks and drinks on consumption, intentions, and perception, and to examine the effects of potential moderators or mediators. The search was conducted in six selected databases and grey literature sources, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for the scoping review process (PRISMA-ScR) guidelines. After screening 5562 articles, 30 articles comprising 47 intervention studies were included. Twelve of 15 studies found a significant effect in lowering the actual or intended consumption when a single smaller package was offered compared with a single larger package. When the total serving size was held constant between varying package conditions, such as a multipack, single package, or unpackaged, the results on the actual and intended consumption were inconsistent and varied according to the presence of moderators. Overall, these findings suggest that an overall reduction in the size of a single package is a more promising strategy than providing multipacks to reduce consumption. Changes to the current food environment to promote single smaller packages of EDNP snacks and drinks are necessary to support the better selection of appropriate portion sizes and reduce consumption.

The impact of food packaging on measured food intake: A systematic review of experimental, field and naturalistic studies

Chronic, excess energy intake contributes to overweight and obesity. Solutions are needed to guide consumers towards portion control, especially for high energy density (HED), palatable foods. Food packaging, a key element of the eating environment, offers a potential solution. To investigate whether packaging design influences measured food intake, a systematic search was undertaken in four electronic databases (Ovid Medline; Ovid PsycInfo; Ovid Embase and Web of Science) across the previous decade. This process yielded 1671 discrete papers, of which 23 articles containing 40 relevant studies were retrieved. Most (n = 36) of the manipulated packaging features influenced consumption quantity with the largest effect sizes observed for packaging which guided consumers either by on-pack cues or structural features. For example, images on the front of the pack, packaging size, as well as partitioning and resealability all helped to reduce food intake. However, individual differences and attentional focus mediate packaging effects. Overall, packaging features can help to limit intake of HED foods and increase intake of nutrient-dense foods (e.g., carrots). Future studies on packaging for portion control (downsizing) might benefit from long term, randomised control trials to test effects outside of the laboratory context and applied to everyday consumer usage.

The effects of salience of the sound of food on consumption

In order to promote their products, food marketers use labels (e.g., crunchy) to make salient the sound created by the food when it is eaten. Will merely making the sound of the food salient (without changing its actual sound) affect consumption? The extant literature is silent on this question. Addressing this gap, we propose that the mere salience of the food's sound can impact consumption. In three studies, we find that the salience of the food's sound increases consumption because it enhances consumers' auditory experience of the sound of food and increases taste evaluations. However, the salience of the food's sound decreases consumption when experience of the food's sound is impaired or when consumption monitoring is high. The paper's findings advance research on auditory perceptions of food, food labeling, and food consumption, and offer guidance on how to enhance enjoyment and prevent overeating of sound-salient food.

Lower socioeconomic status is associated with higher intended consumption from oversized portions of unhealthy food

Socioeconomic status is one of the strongest predictors of obesity, and of living in deprived neighbourhoods with unhealthy food environments. Little is known, however, about the psychological processes that translate features of such environments into socioeconomic differences in eating behaviour. One important feature of unhealthy food environments is the prevalence of oversized portions of unhealthy food. The present study tested whether individuals with lower socioeconomic status intend to consume more from large portions than those with higher socioeconomic status, and examined the psychological processes underlying this effect. A large-scale online experiment was conducted in which participants (N = 511) indicated how much they would eat from small and large portions of healthy and unhealthy snacks. The mediating effects of trait impulsivity and perceptions of how much was considered appropriate to eat were also assessed. Participants with lower socioeconomic status intended to eat more from the large portions than from the small portions of the unhealthy snacks, which would equate to a potential 15-22% increase in energy intake. These effects were partially mediated by trait impulsivity and perceptions of how much is appropriate to eat. These findings point to a significant health burden of low socioeconomic status: when exposed to unhealthy food environments, specific psychological processes might increase the amount of unhealthy food those with lower socioeconomic intend to consume. This study critically informs the emerging understanding of the psychology of socioeconomic status and eating behaviour.

Priming food intake with weight control cues: systematic review with a meta-analysis

BACKGROUND

A growing number of studies suggest that exposure to cues which are associated with weight control can prime or prompt controlled food intake in tempting food environments. However, findings are mixed and understanding which types of cues and for whom such cues may be most effective is needed to inform subsequent research and societal applications. A systematic review and meta-analysis were conducted to evaluate the effects of exposure to weight control cues compared with control cues on food intake.

METHODS

PsycINFO, Medline, Embase and Web of Science were searched using key terms. Hedge's g was used to calculate effect sizes based on mean food intake, standard deviations and sample sizes extracted from relevant publications and, a random effects model was used for the meta-analysis.

RESULTS

Twenty-five articles consisting of 26 studies were eligible. Data from 25 studies (31 effect sizes) were available for the meta-analysis. Overall, weight control cues reduced food intake, albeit to a trivial effect (ES: -0.149, 95% CI: -0.271 to - 0.027). Subgroup analyses when studies which induced negative affect were removed showed that for individuals with strong weight control goals the effect was small-to-moderate (ES: -0.440, 95% CI: -0.718 to - 0.163), whereas for individuals with weak weight control goals this effect was trivial and non-significant (ES: 0.014, 95% CI: -0.249 to 0.278). Cue type and level of engagement did not significantly moderate the effect; however, specific cues (low-calorie foods and thin models) and attended engagement yielded significant effects. Caution is needed interpreting these findings as most studies were rated with high risk of bias and a number of studies could not be included in the subgroup analyses.

CONCLUSIONS

Based on the data available, weight control cues reduce food intake in individuals with strong weight control goals. Further research is needed to explore longer term effects of cue exposure and confirm underlying mechanisms. PROSPERO registry#CRD42016052396.

The Hunger Games: Using hunger to promote healthy choices in self-control conflicts

The majority of existing research and conventional wisdom would advise against shopping on an empty stomach as hunger is assumed to encourage impulsive choices that typically lead to self-control failure (i.e., favouring short-term gratifications at the expense of long-term goals). Nonetheless, through two studies the current research aims to demonstrate that hungry consumers would not always be disadvantaged when encountering a self-control conflict involving a trade-off choice between a healthy vs. a more palatable but unhealthy choice. Particularly we posit that the choice outcome of the self-control conflict is dependent on contextual cues, such that hungry consumers with the tendency to make fast decisions could benefit from following a social proof heuristic promoting the healthy options. In Study 1, we indeed observed participants' self-reported hunger to be negatively associated with state self-control, but as most participants generally experienced low levels of hunger we did not observe apparent effects of hunger on food choice (DV), and correspondingly the potential influence of the social proof heuristic in moderating the choice outcome. However, in Study 2 where hunger was manipulated, we found hungry participants making significantly less healthy choices than satiated participants, but a social proof heuristic mitigated this effect (i.e., in the presence of social proof heuristic hungry participants made just as many healthy food choices as satiated participants; and hungry participants made more healthy choices in the social proof condition than in the no heuristic condition). These findings support our approach of providing contextual cues in the environment in order to work with, rather than against, the impulsivity triggered by hunger to promote successful self-control behaviours.

Restrained Eating and Food Cues: Recent Findings and Conclusions

PURPOSE OF REVIEW

The purposes of the present review are to organize the recent literature on the effects of food cues on restrained and unrestrained eaters and to determine current directions in such work.

RECENT FINDINGS

Research over the last several years involves both replicating the work showing that restrained eaters respond to attractive food cues by eating more but unrestrained eaters show less responsiveness and extending this work to examine the mechanisms that might underlie this differential responsiveness. Labeling a food as healthy encourages more eating by restrained eaters, while diet-priming cues seem to curtail their consumption even in the face of attractive food cues. Work on cognitive responses indicates that restrained (but not unrestrained) eaters have both attention and memory biases toward food cues. Restrained eaters attend more strongly to food- and diet-related cues than do unrestrained eaters, as evidenced in both their eating behavior and their attention and memory responses to such cues. These effects interact with expectations and manner of presentation of such cues. What remains to be understood is the meaning and mechanism of the attention bias toward food cues in restrained eaters and the implications of such bias for overeating and overweight more broadly speaking.

Health goal priming as a situated intervention tool: how to benefit from nonconscious motivational routes to health behaviour

Recent research has shown the limited effects of intentions on behaviour, so that novel methods to facilitate behaviour change are needed that do not rely on conscious intentions. Here, it is argued that nonintentional effects on health behaviour, such as the effects of habits, impulses, and nonconscious goals, occur through the activation of cognitive structures by specific situations. Interventions should therefore be situated to change these effects, either by changing the critical cognitive structures (training interventions), or by changing which cognitive structures get activated (cueing interventions). The current article presents this framework for situated interventions, as well as examples of interventions of each type. Then, it introduces goal priming as a cueing intervention tool to activate health goals and thus facilitate healthier behaviour, even in tempting situations that typically activate short-term hedonic goals. Following a review of empirical evidence, five principles for the effective application of health goal primes are proposed, namely (1) to target individuals who value the primed goals, (2) by activating their specific motivation, (3) through effective cues (4) that attract attention at the right time. Finally, (5) an effective goal-directed behaviour needs to be known and accessible to the primed individual. These principles are illustrated with examples of different health behaviours in order to facilitate their application for successful behaviour change.