Large Portions Encourage the Selection of Palatable Rather Than Filling Foods

Healthy Eating in Population Models of Nutrition: Asian Diet Style Summary

The population of Japan and Okinawa is known for the longest life expectancy, which many researchers rightly associate with the nature of nutrition existing in these territories. The Japanese diet and Okinawan diet, along with other traditional diets, are real examples of historically established sustainable patterns of healthy eating. Asian eating styles have marked differences from European eating patterns, not only in differences in food sources, but also in eating habits. The article presents the historical, climatic and cultural features of these diets; the issues of food composition, energy and nutritional value of these models of nutrition are considered in detail with an analysis of the differences existing between them; highlights the benefits of products grown mainly in Japan, which are ration-forming for the population of this country; as well as the results of scientific studies on the protective effect of the Japanese and Okinawan diets on human health and disease prevention.

Portions selected to stave off hunger are reduced when food is presented in an 'unusual' food-to-mealtime context: An implication for implicit satiety drivers

Research suggests that the role of expected satiety in influencing portion-size selection is reduced when food is presented in unusual food-to-mealtime contexts; however, the underlying mechanism has not been explored. Other research has revealed that different implicit satiety drivers (e.g., to stop momentary hunger or obtain complete fullness) are associated with different perceived levels of stomach fullness, portion-size selections and can change on instruction. The current study explored whether changes in expected satiety and ideal portions in congruous vs incongruous contexts can be explained by changes in implicit satiety drivers. Another aim was to investigate a previous exploratory finding suggesting that portions selected to stave off hunger are reduced when foods are presented in unusual food-to-mealtime contexts. At two trials (breakfast/lunch), participants (n = 40) selected a portion of typical lunch (pasta) and breakfast (porridge) foods via a psychophysical computer-based method 1) to stave off hunger for 5 h, and 2) as an ideal portion. Participants also indicated their perceived level of stomach fullness associated with 1) each portion, and 2) five implicit satiety drivers. Results revealed that a smaller average portion was selected to stave off hunger in incongruous (vs congruous) food-to-mealtime contexts (531 ± 229 vs 575 ± 236 kcal) (p = 0.008). This suggests that expected satiety is influenced by momentary context; foods are perceived to be more satiating when consumed in unusual (vs usual) contexts. Results also showed that implicit satiety drivers are malleable in regard to the portion size associated with a perceived level of stomach fullness and that this can vary contextually. These findings provide initial evidence to explain the psychological mechanism underlying the contextual differences observed in portion-size selections. Future work should explore longer-term impacts of consuming foods in unusual contexts.

The physiological control of eating: signals, neurons, and networks

During the past 30 yr, investigating the physiology of eating behaviors has generated a truly vast literature. This is fueled in part by a dramatic increase in obesity and its comorbidities that has coincided with an ever increasing sophistication of genetically based manipulations. These techniques have produced results with a remarkable degree of cell specificity, particularly at the cell signaling level, and have played a lead role in advancing the field. However, putting these findings into a brain-wide context that connects physiological signals and neurons to behavior and somatic physiology requires a thorough consideration of neuronal connections: a field that has also seen an extraordinary technological revolution. Our goal is to present a comprehensive and balanced assessment of how physiological signals associated with energy homeostasis interact at many brain levels to control eating behaviors. A major theme is that these signals engage sets of interacting neural networks throughout the brain that are defined by specific neural connections. We begin by discussing some fundamental concepts, including ones that still engender vigorous debate, that provide the necessary frameworks for understanding how the brain controls meal initiation and termination. These include key word definitions, ATP availability as the pivotal regulated variable in energy homeostasis, neuropeptide signaling, homeostatic and hedonic eating, and meal structure. Within this context, we discuss network models of how key regions in the endbrain (or telencephalon), hypothalamus, hindbrain, medulla, vagus nerve, and spinal cord work together with the gastrointestinal tract to enable the complex motor events that permit animals to eat in diverse situations.

No evidence of flavour-nutrient learning in a two-week 'home exposure' study in humans

Flavour-nutrient learning is robust in animals but remains elusive in humans. Recent evidence suggests flavour-nutrient learning may be more likely to occur with beverages that contain relatively few calories (compared to no calories), while others show that learned associations can influence satiation, without an effect on preference. The objective of this research was to determine whether acquired liking for a caloric drink could be observed in a 'home learning' context over 2 weeks, and whether it is impacted by viscosity. In combination, we also explored changes in learning relating to fullness and expected satiety. In a double-blind study, participants (N = 83; BMI = 23.3 kg/m²) were randomly allocated to one of four groups differing in either calories (0 kcal vs. 112.5 kcal) or viscosity (low vs. high) and consumed a novel-flavoured drink over 15 days. Measures of flavour (10 ml sample) and beverage liking, grip force (a measure of beverage reward value), fullness, and expected satiety were taken at the start and the end of the study. While the high-viscous beverages were less liked (M = 40.3 mm, SD = 24.7) than the low viscous beverages (M = 64.4 mm, SD = 15.3; p = .022), there was no evidence that repeated exposure to a calorie-containing beverage impacted subsequent liking for the flavour (p = .115) or for the beverage (p = .448), grip force (ps > .26), fullness, and expected satiety (ps > .12). Accordingly, we conclude that we found no evidence of flavour-nutrient learning and flavour-satiety learning. This null finding accords with previous observations indicating that humans do not acquire flavour-nutrient associations as readily as some non-human animals.

A review of evidence supporting current strategies, challenges, and opportunities to reduce portion sizes

Although there is considerable evidence for the portion-size effect and its potential impact on health, much of this has not been successfully applied to help consumers reduce portion sizes. The objective of this review is to provide an update on the strength of evidence supporting strategies with potential to reduce portion sizes across individuals and eating contexts. Three levels of action are considered: food-level strategies (targeting commercial snack and meal portion sizes, packaging, food labels, tableware, and food sensory properties), individual-level strategies (targeting eating rate and bite size, portion norms, plate-cleaning tendencies, and cognitive processes), and population approaches (targeting the physical, social, and economic environment and health policy). Food- and individual-level strategies are associated with small to moderate effects; however, in isolation, none seem to have sufficient impact on food intake to reverse the portion-size effect and its consequences. Wider changes to the portion-size environment will be necessary to support individual- and food-level strategies leading to portion control.

Identifying Barriers to Reducing Portion Size: A Qualitative Focus Group Study of British Men and Women

Reducing portion size might reduce meal satisfaction, which could minimize adherence to portion size interventions. The present study sought to identify the perceived barriers for consumers to eat smaller portions. A secondary aim explored the relative contribution of enjoyment of taste and post-meal fullness as determinants of meal satisfaction. Focus groups (N = 42) evaluated consumers' feelings toward a small reduction in portion size. Thematic analysis of written free association tasks and open-ended group discussions revealed that most participants expected to feel hungry and unsatisfied, which motivated them to consume something else. However, others expected to feel comfortable, healthy, and virtuous. The acceptability of the reduced portion was also determined by meal characteristics (e.g., time and setting) and individual characteristics (e.g., predicted energy requirements). Compared to post-meal fullness, enjoyment of taste was perceived to be the more important determinant of meal satisfaction. In conclusion, interventions should present portion reduction as a marginal modification with little physiological consequence to energy reserves, while emphasizing the positive feelings (e.g., comfort, satisfaction, and self-worth) experienced after consuming a smaller portion. Additionally, focusing on taste enjoyment (rather than fullness) might be a useful strategy to maintain meal satisfaction despite a reduction in meal size.

Food portion size influences accompanying beverage selection in adults

When trying to reduce food portion size, it is important that meal satisfaction is, as far as possible, preserved. Otherwise, individuals may select accompaniments to the meal (e.g., snacks, beverages) to achieve satisfaction and, in doing so, negate any benefit of the original portion size reduction. This study investigated whether varying portion sizes of food would influence choice of accompanying beverages. That is, when presented with a food portion size that is smaller or larger than their ideal, an individual may compensate by choosing a beverage based on its satiating and/or orosensory properties to balance the expected satiation and satisfaction of a meal. Data from an online interactive study (n = 93) was analysed using multilevel ordinal logistic regression models. Food portion size (100, 300, 500, 700, or 900 kcal) predicted beverage choice (water, low-energy sweetened beverage, high-energy sweetened beverage). For example, the sweetened beverages were more likely to be selected with small food portion sizes (p < .001). Participant ideal food portion size did not interact with this relationship. Participants appear to have recognised that sweetened beverages provide flavour and/or energy, and used them to compensate for a smaller meal. While switching to a low-energy beverage with an increased food portion size is advantageous for energy balance, choosing a high-energy beverage with a decreased food portion size is likely to be detrimental for those attempting to reduce energy intake and body weight.

Expectations About Satiety and Thirst Are Modified by Acute Motivational State

Prior research has shown that consumers have clear and measurable expectations about the likely effects of food and drink items on their appetite and thirst, which are acquired with experience and influenced by a product's taste and texture. What is unclear is whether expression of these expectations also varies with current appetitive state. It is possible that current appetite could increase or decrease the relevance of these expectations for future food choice and magnify a product's expected impact on appetite. To test this, we contrasted expectations about satiety and thirst for four products consumed 2 h after an appetite manipulation at breakfast, achieved through ad libitum access to low-energy drinks only (hunger condition), cereal only but no drinks (thirst condition) or both foods and drinks (sated condition). The test products were two soups and two drinks, with a thicker and thinner version of each product type to act as positive control to ensure sensitivity in detecting differences in expectations. For satiety, the predicted differences between products were seen: soups and thicker products were expected to be more filling and to suppress subsequent hunger more than drinks and thinner products, but these differences were more pronounced in the hunger than thirsty or sated conditions. Being thirsty also enhanced expectations of how much drinks would appease immediate thirst. Overall the data show that expectations were adjusted subtly by a person's current appetitive state, suggesting that we have mechanisms that highlight the most important features of a product at the time when it may be most beneficial to the consumer.

Breaking the fast: Meal patterns and beliefs about healthy eating style are associated with adherence to intermittent fasting diets

Many believe that eating three meals each day is healthy and that skipping meals can be detrimental. What remains unclear is whether this belief undermines attempts to restrict energy intake by skipping meals. In an online survey, participants (N = 312) with experience of intermittent fasting (IF) reported their beliefs about healthy meal and snack frequency, as well as their non-fasting-dasy and fasting-day eating patterns. They also reported their level of concern with fasting-day meal patterns and their concern to generate fullness when selecting foods. Individuals currently following an IF diet (Current-IF dieters) and those who had previously attempted an IF diet but were non-adherent (Former-IF dieters) took part. Former-IF dieters were more likely to believe that it is healthy to eat three meals a day, punctuated by several snacks. On fasting-days, Former-IF dieters were also more likely to eat breakfast, a mid-morning snack, lunch, and a mid-afternoon snack whereas Current-IF dieters tended to save their eating for dinner and a late evening snack. Former-IF dieters were also more likely to be concerned about the negative consequences of missing a meal, to eat in anticipation of future hunger, and to prioritise fullness over taste when selecting foods. These findings reveal how beliefs about a healthy eating style can play an important role in shaping dietary patterns. Interventions aimed at modifying beliefs about healthy meal patterns may promote IF diet adherence.

Protein for Life: Towards a focussed dietary framework for healthy ageing

'Ageing well' has been highlighted as an important research area by the World Health Organization. In the UK, healthy ageing has been identified as a priority research area by multiple Research Councils and is a key NHS priority. Sarcopaenia, the decline of muscle mass/strength and a key component of healthy ageing, can have a major impact on quality of life and is associated with premature mortality. Increasing protein intake at all stages of the life course may help to reduce the rate of muscle decline and the onset of associated health conditions. However, there is a lack of understanding of the social, demographic and psychological drivers of food choices surrounding protein intake. This report describes the multidisciplinary approach that has been adopted by the Protein for Life project to create a framework for the development of palatable, cost-effective higher-protein foods suitable for an ageing population.

Research into food portion size: methodological aspects and applications

Portion sizes for certain foods have been increasing dramatically in recent years alongside obesity rates, concurring with the phenomenon of the portion size effect (more is consumed when more is offered). Portion size may be defined based on different purposes such as for dietary assessment, or therapeutic advice or food labelling, resulting in a variety of measurement methods and specifications. This situation has resulted in disagreements on establishing portion size recommendations by manufacturers, food distributors, restaurants, health professionals and policy makers, contributing to confusion amongst consumers on the amounts of food to be consumed, and potentially increasing the likelihood of overeating and other obesity-related behaviours. Such variability is also reflected in the research field making comparison across studies on portion size difficult. The aim of this review is to provide an overview of definitions and methods used in research to evaluate portion-size related outcomes, including methods to estimate amounts consumed by individuals as part of dietary assessment; methods to analyse cognitive mechanisms related to portion size behaviour; and methods to evaluate the impact of portion size manipulations as well as individual plus environmental factors on portion size behaviour. Special attention has been paid to behavioural studies exploring portion size cognitive processes given the lack of previous methodological reviews in this area. This information may help researchers, clinicians and other stakeholders to establish clearer definitions of portion size in their respective areas of work and to standardise methods to analyse portion size effects.

The Role of the Japanese Traditional Diet in Healthy and Sustainable Dietary Patterns around the World

As incomes steadily increase globally, traditional diets have been displaced by diets that are usually animal-based with a high content of “empty calories” or refined sugars, refined fats, and alcohol. Dietary transition coupled with the expansion of urbanization and lower physical activity have been linked to the global growth in the prevalence of obesity, overweight and life style-related non-communicable diseases. The challenge is in how to reverse the trend of high consumption of less healthy food by more healthful and more environmentally sustainable diets. The increasing recognition that each individual has specific needs depending on age, metabolic condition, and genetic profile adds complexity to general nutritional considerations. If we were to promote the consumption of low-energy and low salt but nutritious diets, taste becomes a relevant food quality. The Japanese traditional diet (Washoku), which is characterized by high consumption of fish and soybean products and low consumption of animal fat and meat, relies on the effective use of umami taste to enhance palatability. There may be a link between Washoku and the longevity of the people in Japan. Thus Washoku and umami may be valuable tools to support healthy eating.

Individual variability in preference for energy-dense foods fails to predict child BMI percentile

Many studies show that higher dietary energy density is associated with greater body weight. Here we explored two propositions: i) that child BMI percentile is associated with individual differences in children's relative preference for energy-dense foods, ii) that child BMI percentile is associated with the same individual differences between their parents. Child-parent dyads were recruited from a local interactive science center in Bristol (UK). Using computerized tasks, participants ranked their preference and rated their liking for a range of snack foods that varied in energy density. Children (aged 3–14 years, N = 110) and parents completed the tasks for themselves. Parents also completed two further tasks in which they ranked the foods in the order that they would prioritize for their child, and again, in the order that they thought their child would choose. Children preferred (t(109) = 3.91, p < 0.001) and better liked the taste of (t(109) = 3.28, p = 0.001) higher energy-dense foods, and parents correctly estimated this outcome (t(109) = 7.18, p < 0.001). Conversely, lower energy-dense foods were preferred (t(109) = − 4.63, p < 0.001), better liked (t(109) = − 2.75, p = 0.007) and served (t(109) = − 15.06, p < 0.001) by parents. However, we found no evidence that child BMI percentile was associated with child or parent preference for, or liking of, energy-dense foods. Therefore, we suggest that the observed relationship between dietary energy density and body weight is not explained by individual differences in preference for energy density.

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Higher dietary energy density (ED) is associated with greater body weight.

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A novel, computerized task was implemented to assess preference for ED.

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Children's and parent's relative preferences for ED were measured.

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Variation in relative ED preference was not associated with child BMI percentile.

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Alternate explanations of the association between dietary ED and BMI are discussed.