Pre-exposure to diet-congruent food reduces energy intake in restrained dieting women

The influence of supraliminal priming on energy density of food selection: a randomised control trial

Background

Many people exercise because they know it is good for their health. Although this is true, it can make us feel deserving of a reward and lead us to eat more indulgent, less healthy food than if we had not done any exercise. Generally, lower energy-dense (LED) foods are recognised as healthier choices than higher energy-dense (HED) options. Despite our intention to make healthy choices, seeing tempting higher-calorie foods on offer often side-tracks us. Priming is a psychological tool that makes specific changes to our environment that remind us of our motivation to be healthy. This makes it easier to choose a healthier option, by nudging us towards it without us even realising. However, it is currently unclear which method of priming achieves the best results.

Aims

Our study explores whether priming people to expect they will receive LED food leads them to make this healthier choice after exercise, even when also offered tempting less healthy HED foods at the moment of selection.

Methods

Our study observed the foods selected by university athletes after their sports matches. Before the match, half of the participants were primed by asking them to choose a LED snack from the options we offered, which they would receive after the match. The remaining half of participants were not asked this same question. To distract the athletes from our observation of their food choices, participants completed a task prior to choosing their snack, which was disguised as a ‘thank you’ for taking part.

Results

Overall, we found the priming group did not choose LED foods significantly more than the control group, hence priming did not increase LED food selection.

Conclusion

Importantly, our results indicate that priming must be more noticeable to achieve its goal. Additionally, we demonstrated that priming may be less successful for young athletic individuals, compared to older and more overweight adults recruited in other studies. This highlights the importance of studying a broader demographic range of individuals from the general population. We support future research into this area, which will help us to tweak priming to achieve the best outcomes.

Trial registration

ISRCTN Registry, ISRCTN74601698. Date registered: 02/10/2020 (retrospectively registered).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40359-021-00554-1.

Nudge interventions to reduce fish sauce consumption in Thailand

High sodium consumption is one of the four major risk factors contributing to non-communicable diseases around the world. Thailand has one of the highest rates of sodium consumption, with fish sauce being one of the main sources. The aim of this study was to examine whether changes in the micro-environment factors can affect fish sauce consumption behavior in a university setting in Thailand. We implemented four interventions (with one control) in five canteens across a Thai university. The study design was a Latin square, where the five canteens were randomized over five weeks to implement four interventions plus a control. Our interventions included behavior-oriented, cognitive-oriented, and affective-oriented nudges aimed to reduce the amount of fish sauce people add to their noodles during lunchtime at the university canteens. Results indicate that a simple change in how fish sauce was served can reduce fish sauce consumption. Serving fish sauce in a bowl with a spoon reduced the amount of fish sauce used per noodle bowl by 0.25 grams, compared to the normal condition where fish sauce is served in a bottle. Using a specially-designed spoon with a hole induced a larger reduction of 0.58 grams of fish sauce used per bowl. The other two interventions, cognitive- and affective- oriented nudges, also showed reductions of fish sauce usage, but the differences were not statistically significant. The findings can be used for policy implementation to advocate the use of a smaller sized spoon and a bowl to serve fish sauce instead of a bottle to reduce sodium consumption among Thai people.

Regulating food craving: From mechanisms to interventions

Craving, defined here as a strong desire to eat, is a common experience that drives behavior. Here we discuss the concept of craving from historical, physiological, and clinical perspectives, and review work investigating the effects of cue reactivity and cue-induced craving on eating and weight outcomes, as well as underlying neural mechanisms. We also highlight the significance of cue reactivity and craving in the context of our "toxic food environment" and the obesity epidemic. We then summarize our work developing the Regulation of Craving (ROC) task, used to test the causal effects of cognitive strategies on craving for food and drugs as well as the underlying neural mechanisms of such regulation. Next, we review our recent development of a novel ROC-based intervention that trains individuals to use cognitive strategies to regulate craving, with promising effects on subsequent food choice and caloric consumption. We end by discussing future directions for this important line of work.

Snack Portion Sizes for Preschool Children Are Predicted by Caregiver Portion Size, Caregiver Feeding Practices and Children's Eating Traits

Caregivers are mostly responsible for the foods young children consume; however, it is unknown how caregivers determine what portion sizes to serve. This study examined factors which predict smaller or larger than recommended snack portion sizes in an online survey. Caregivers of children aged 2 to 4 years were presented with 10 snack images, each photographed in six portion sizes. Caregivers (n = 659) selected the portion they would usually serve themselves and their child for an afternoon snack. Information on child eating traits, parental feeding practices and demographics were provided by caregivers. Most caregivers selected portions in line with recommended amounts for preschool children, demonstrating their ability to match portion sizes to their child′s energy requirements. However, 16% of caregivers selected smaller than recommended low energy-dense (LED, e.g., fruits and vegetables) snacks for their child which was associated with smaller caregiver′s own portion size, reduced child food liking and increased satiety responsiveness. In contrast, 28% of caregivers selected larger than recommended amounts of high energy-dense (HED, e.g., cookies, crisps) snacks for their child which were associated with larger caregiver′s own portion size, greater frequency of consumption, higher child body mass index (BMI), greater pressure to eat and lower child food liking. These findings suggest that most caregivers in this study select portions adjusted to suit their child′s age and stage of development. Future interventions could provide support to caregivers regarding the energy and nutrient density of foods given the relatively small portion sizes of LED and large portions of HED snacks offered to some children.

The effect of the spatial positioning of a healthy food cue on food choice from a pictorial-style menu

The present study aimed to investigate the effect of the spatial positioning of a healthy food cue in the context of unhealthy food cues on subsequent food choice. Undergraduate women (N = 143) were asked to choose a food from a pictorial-style menu that presented a salad and three unhealthier food options in a horizontal line. The position of the salad was manipulated to be presented either (a) in the middle, (b) at the end, or (c) separated by 5 cm to the right of the line of unhealthier food options. Participants also completed a questionnaire measure of dietary restraint. Participants were significantly more likely to choose the salad when it was presented separately rather than in the middle of the unhealthier food options. This effect was not moderated by dietary restraint. The findings point to the possibility of designing pictorial menus in fast-food outlets in such a way as to subtly nudge people towards making healthier food choices.

It's all in the timing: The effect of a healthy food cue on food choices from a pictorial menu

The contemporary food-rich environment has been consistently linked to unhealthy eating. Emerging research suggests that changing the presentation context of unhealthy foods by introducing a subtle nudge in the form of a healthy food cue may promote healthier dietary choices. This study investigated the effect of the timing of a healthy food cue (before or simultaneously with food options) on food choices. Participants (n = 210) were presented with a pictorial café-style menu displaying a healthy food cue (basket of fruit and vegetables) either on the menu cover or inside the menu, or they received a control menu. Participants were asked to make one choice from each of three menu sections (meals, beverages, afters), and then completed a measure of dietary restraint. As predicted, participants chose a greater proportion of healthy food from the healthy-cue-before menu compared to both the healthy-cue-simultaneous and control menus. Furthermore, this effect was stronger for restrained eaters. The findings demonstrate that the timing of presentation of a healthy food cue is critical, and could be used to inform the design of menus in real-world environments, such as cafés and fast-food outlets, to promote healthier dietary choices.

Do low-calorie sweetened beverages help to control food cravings? Two experimental studies

Low-calorie sweetened (LCS) beverages may help consumers to satisfy hedonic food cravings without violating dieting goals, however this remains unexplored. The present research investigated the effect of priming hedonic eating motivations on ad libitum energy intake in frequent and non-consumers of LCS beverages. It was hypothesised that energy intake would be greater after the hedonic eating prime relative to a control prime in non-consumers, but that frequent LCS beverage consumers would be protected from this effect. In Study 1 (N = 120), frequent and non-consumers were exposed to either chocolate or neutral cues (craving vs. control condition) and then completed a beverage-related visual probe task with concurrent eye-tracking. Ad libitum energy intake from sweet and savoury snacks and beverages (including LCS) was then assessed. Study 2 followed a similar protocol, but included only frequent consumers (N = 172) and manipulated the availability of LCS beverages in the ad libitum eating context (available vs. unavailable). Measures of guilt and perceived behavioural control were also included. In Study 1, as hypothesised, non-consumers showed greater energy intake in the craving condition relative to the control condition, but frequent consumers had similar energy intake in both conditions. Frequent consumers (but not non-consumers) also demonstrated an attentional bias for LCS beverage stimuli compared to both sugar and water stimuli. In contrast, in Study 2 frequent consumers showed greater energy intake in the craving condition relative to the control condition; however, overall energy intake was significantly greater when LCS beverages were unavailable compared to when they were available. Ratings of guilt were higher and perceived control was lower in the LCS-unavailable condition relative to the LCS-available condition. Conclusions: LCS beverages did not consistently protect consumers from craving-induced increases in energy intake. However, frequent consumers consumed fewer calories overall when LCS beverages were available (relative to unavailable), as well as perceiving more control over their food intake and feeling less guilty.

To Message or Browse? Exploring the Impact of Phone Use Patterns on Male Adolescents' Consumption of Palatable Snacks

Surveys of mobile phone usage suggest that adolescents habitually use their phones while eating. In this study, we explored whether the manner in which one uses a mobile phone – to engage in a social or non-social activity – can affect appetite regulation. Participants were fifty male adolescents randomly assigned to engage in one of the following phone-based activities: (1) sending and receiving messages (social activity), or (2) reading a neutral article (non-social activity). When given the opportunity to snack, participants in the messaging group consumed more snacks that those who read the article. Our findings correspond to a large literature emphasizing social influences on food intake, and suggest that phone use patterns may predispose an individual to overeating.

Frequency of Consuming Foods Predicts Changes in Cravings for Those Foods During Weight Loss: The POUNDS Lost Study

OBJECTIVE

Food cravings are thought to be the result of conditioning or pairing hunger with consumption of certain foods.

METHODS

In a 2-year weight loss trial, subjects were randomized to one of four diets that varied in macronutrient content. The Food Craving Inventory (FCI) was used to measure cravings at baseline and at 6 and 24 months. Food intake was also measured at those time points. To measure free-living consumption of food items measured in the FCI, items on the FCI were matched to the foods consumed from the food intake assessments. Secondarily, the amount of food consumed on food intake assessments from foods on the FCI was analyzed.

RESULTS

Three hundred and sixty-seven subjects with overweight and obesity were included. There was an association between change from baseline FCI item consumption and change in cravings at months 6 (P < 0.001) and 24 (P < 0.05). There was no association between change from baseline amount of energy consumed per FCI item and change in cravings.

CONCLUSIONS

Altering frequency of consuming craved foods is positively associated with cravings; however, changing the amount of foods consumed does not appear to alter cravings. These results support the conditioning model of food cravings and provide guidance on how to reduce food cravings.

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.

Insta-Grams: The Effect of Consumer Weight on Reactions to Healthy Food Posts

Each day, social networking sites become increasingly inundated with food imagery. Since many of these images are of fresh, vibrant, and healthy eats, photo sharing of food through social media should have a long-term positive effect on consumption habits. Yet, obesity rates in the United States continue to rise, suggesting that people are spending more time posting images of healthy foods and paying less attention to the actual foods they consume. This confounding relationship could be explained by consumer weight, in that overweight consumers desire to engage with social media maybe for the purpose of expressing, presenting, and identifying with a healthy lifestyle. In the context of food posts, individuals higher in body mass index may be more likely to engage in social media activity (e.g., likes, shares, comments) that validates healthy food choices to others in their online community. A between-subjects experimental design tested this proposed effect using a manipulated Instagram post of a healthy food item (i.e., black bean veggie burger). Results indicate that obese individuals are more likely to engage with healthy food posts compared with their normal weight and overweight counterparts. The effect is even more pronounced when posts are absent of prior social media activity. Based upon these results, obese individuals are encouraged to establish and maintain social network connections with others who routinely post images of healthy food in their social media feeds. Limitations and directions for future research are provided.

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.

Effects of olfactory sense on chocolate craving

In the present study, we assessed the effect of the olfactory sense on chocolate craving in college females. Building on previous research by Kemps and Tiggemann (2013), we hypothesized that a fresh scent would decrease one's craving level for chocolate food. While the precursor study only addressed the decrease of chocolate craving, we also hypothesized that a sweet scent would increase one's craving level for chocolate foods. In the present experiment, participants rated their craving levels after viewing images of chocolate foods and inhaling essential oils: one fresh (Slique™ essence), and one sweet (vanilla). Results supported both of the hypotheses: inhaling a fresh scent reduced females' craving levels; similarly, when a sweet scent was inhaled, the participants' craving levels for chocolate food increased. These findings are particularly beneficial for women seeking weight loss and the findings can be applied in contexts such as weight loss programs, therapy, and maintenance programs, even beyond college settings. The results are particularly useful for helping women regarding stimuli that might serve as triggers for chocolate cravings.

The Role of Odor-Evoked Memory in Psychological and Physiological Health

This article discusses the special features of odor-evoked memory and the current state-of-the-art in odor-evoked memory research to show how these unique experiences may be able to influence and benefit psychological and physiological health. A review of the literature leads to the conclusion that odors that evoke positive autobiographical memories have the potential to increase positive emotions, decrease negative mood states, disrupt cravings, and reduce physiological indices of stress, including systemic markers of inflammation. Olfactory perception factors and individual difference characteristics that would need to be considered in therapeutic applications of odor-evoked-memory are also discussed. This article illustrates how through the experimentally validated mechanisms of odor-associative learning and the privileged neuroanatomical relationship that exists between olfaction and the neural substrates of emotion, odors can be harnessed to induce emotional and physiological responses that can improve human health and wellbeing.

Impact of Perceived Healthiness of Food on Food Choices and Intake

Healthy eating is an important determinant of health, but adherence to dietary guidelines remains a public health concern. Identifying factors that impact dietary habits is therefore important to facilitate healthy eating. One widely used strategy to help consumers make healthier food choices is nutrition information, such as labeling and claims. Despite the intention of these strategies to improve decision making, they can also be misunderstood or misinterpreted by consumers. The aim of this review is to explore food perceptions by examining how cognitive factors influence perceived healthiness of food, and the impact of perceived healthiness of food on food choices and intake. Overall findings of this review suggest that cognitive factors, such as type of food and branding, significantly contribute to judgmental bias and have an impact on perceived healthiness while not consistently or systematically influencing choice and intake.

Food cue reactivity and craving predict eating and weight gain: a meta-analytic review

According to learning-based models of behavior, food cue reactivity and craving are conditioned responses that lead to increased eating and subsequent weight gain. However, evidence supporting this relationship has been mixed. We conducted a quantitative meta-analysis to assess the predictive effects of food cue reactivity and craving on eating and weight-related outcomes. Across 69 reported statistics from 45 published reports representing 3,292 participants, we found an overall medium effect of food cue reactivity and craving on outcomes (r = 0.33, p < 0.001; approximately 11% of variance), suggesting that cue exposure and the experience of craving significantly influence and contribute to eating behavior and weight gain. Follow-up tests revealed a medium effect size for the effect of both tonic and cue-induced craving on eating behavior (r = 0.33). We did not find significant differences in effect sizes based on body mass index, age, or dietary restraint. However, we did find that visual food cues (e.g. pictures and videos) were associated with a similar effect size to real food exposure and a stronger effect size than olfactory cues. Overall, the present findings suggest that food cue reactivity, cue-induced craving and tonic craving systematically and prospectively predict food-related outcomes. These results have theoretical, methodological, public health and clinical implications.

Priming healthy eating. You can't prime all the people all of the time

OBJECTIVE

In the context of a food purchasing environment filled with advertising and promotions, and an increased desire from policy makers to guide individuals toward choosing healthier foods, this study tests whether priming methods that use healthy food adverts to increase preference for healthier food generalize to a representative population.

METHODS

In two studies (Study 1 n = 143; Study 2 n = 764), participants were randomly allocated to a prime condition, where they viewed fruit and vegetable advertisements, or a control condition, with no advertisements. A subsequent forced choice task assessed preference between fruits and other sweet snacks. Additional measures included current hunger and thirst, dietary restraint, age, gender, education and self-reported weight and height.

RESULTS

In Study 1, hunger reduced preferences for fruits (OR (95% CI) = 0.38 (0.26-0.56), p <0.0001), an effect countered by the prime (OR (95% CI) = 2.29 (1.33-3.96), p = 0.003). In Study 2, the effect of the prime did not generalize to a representative population. More educated participants, as used in Study 1, chose more fruit when hungry and primed (OR (95% CI) = 1.42 (1.13-1.79), p = 0.003), while less educated participants' fruit choice was unaffected by hunger or the prime.

CONCLUSION

This study provides preliminary evidence that the effects of adverts on healthy eating choices depend on key individual traits (education level) and states (hunger), do not generalize to a broader population and have the potential to increase health inequalities arising from food choice.

Sensory-specific appetite is affected by actively smelled food odors and remains stable over time in normal-weight women

Understanding overconsumption starts with knowledge of how separate factors influence our eating behavior. Food cues such as food odors are known for their effect on general appetite and sensory-specific appetite (SSA). Active sniffing rather than passive exposure may induce satiation over time. The objective of this study was to investigate how actively sniffing banana odors affects general appetite, SSA, and subsequent food intake. In a crossover study, 61 women actively smelled cups containing natural banana, artificial banana odor, or water (no odor) for 10 min. Treatment order was randomly assigned as much as possible. General appetite and SSA were monitored by using 100-mm visual analog scales during the 10 min of active sniffing, followed by ad libitum intake of banana milkshake. Results showed that SSA was consistently high (+12 mm) during actively sniffing natural or artificial banana odors, with no decrease in SSA over time. Sniffing both banana odors increased the appetite for banana (+11 mm) and other sweet products (+4 mm), whereas the appetite for savory products decreased by 7 mm (all P < 0.01) compared with no odor. Actively sniffing banana odor did not significantly influence food intake (P = 0.68) or general appetite scores (P = 0.06). In conclusion, SSA scores during active sniffing were identical to the SSA found in a similar study that used passive smelling, suggesting that SSA is independent of the manner of sniffing and exposure time. Moreover, sweet/savory categorization may suggest that food odors communicate information about the nutrient composition of their associated foods. These data clearly show the appetizing effects of food odors.

Association between mood and diet quality in subjects with metabolic syndrome participating in a behavioural weight-loss programme: a cross-sectional assessment

BACKGROUND/OBJECTIVE

The interplay between individual's mood fluctuations and nutrition has important health implications. However, little information is available on the relationship between dietary intake and mood state in a population with metabolic syndrome (MetS). The aim of the present study was to evaluate the association between dietary intake and mood state in subjects with MetS.

METHODS

This cross-sectional study was based on the baseline data of 84 volunteers (mean age 49 ± 1 years) recruited into the Metabolic Syndrome Reduction in Navarra-Spain (RESMENA-S) study. Mood state was determined using a mood thermometer visual analogue scale. The dietary intake was assessed with a 48-hours weighted food record, from which a Healthy Eating Index (HEI) score was obtained. Anthropometrical measurements and biochemical parameters were also analysed.

RESULTS

At baseline, a positive association between mood thermometer and HEI was observed. Among the 10 HEI components, vegetables, fruits, calories from lipids, saturated fatty acids, and dietary variety were related with higher mood. Moreover, those participants who consumed more water, fibre, vitamin B6, ascorbic acid, tryptophan, magnesium, and selenium have higher mood.

DISCUSSION

In conclusion, an association between both the overall dietary pattern and isolated nutrients with mood state was observed. The analyses of both dietary patterns and specific nutrients are important to determine the association between mental disorders and dietary intake.

Slimming starters. Intake of a diet-congruent food reduces meal intake in active dieters

Dietary restraint is known to break down in the face of tempting foods. Previous research suggests exposure to cues associated with slimming such as images or odours act as prompts to restrict intake of a tempting snack in dieters. The effects of consuming diet-congruent foods on subsequent intake of a meal have not yet been investigated. Thus, using a repeated measures design 26 female participants (dieters or non-dieters) consumed a diet-congruent (100 kcal salad), hedonic (100 kcal garlic bread) or neutral (0 kcal water) preload. A lexical decision task measured the salience of diet and hedonic thoughts and participants were then offered pizza as a main meal. Appetite sensations were measured throughout the study. Compared to the hedonic and neutral preload, a diet-congruent preload reduced dieters' entire meal intake by 21%. In contrast, non-dieters consumed 9% more in the hedonic preload condition compared to the neutral preload, yet showed no differences between the diet-congruent and other conditions. Salad lowered participants desire to eat and increased fullness compared to garlic bread and water preloads. Dieters were also less hungry after the salad compared to the garlic bread and water preloads. Consuming a diet-congruent first course may prompt lower intake at a meal, in part due to facilitating resolve to refrain from overeating a tempting second course.