Systematic Review and Meta-Analysis on the Effect of Portion Size and Ingestive Frequency on Energy Intake and Body Weight among Adults in Randomized Controlled Feeding Trials

Do nudges need a regulatory push? Comparing the effectiveness and implementation of exemplar nudge (size-based) and non-nudge (price-based) dietary interventions

Changing behaviour across populations is key to improving population health and achieving net zero by 2050, including changing diets. We examine the extent to which nudges, with the potential to contribute to such change, are being implemented alongside traditional approaches. We compare the effectiveness and extent of implementation into policy of two interventions to improve diets: size-based interventions that alter portion, package or tableware size, commonly considered a nudge; and, price-based interventions, including food-item taxes, not considered a nudge. We conducted four rapid reviews: two for systematic reviews with meta-analyses aimed to determine the effectiveness of size-based and price-based interventions, respectively; and two for reports to estimate the extent to which size-based and price-based interventions have been implemented in health or environment policies of governments, public authorities, or private sector organisations, at national or sub-national levels. Both sets of interventions were consistently found in research studies to be effective at reducing consumption and purchasing of unhealthy products, but price-based interventions have been implemented in policies far more often than size-based ones. At least 118 countries have implemented taxes on sugar sweetened beverages (SSBs), and 42 countries have implemented taxes on unhealthy foods. In contrast, we identified 20 reports of size-based interventions implemented at sub-national level, of which only one involved regulation. Explaining and reversing the lack of implementation of size-based interventions and other effective nudges merits prioritisation to help realise global ambitions to improve population health and achieve net zero by 2050.

Investigating eating architecture and the impact of the precision of recorded eating time: a cross-sectional study

BACKGROUND

The precision of recorded eating times directly affects the estimation of eating architecture, that is, size, timing, and frequency of eating. The impact of imprecise timing on estimates and associations of eating architecture with health remains unclear.

OBJECTIVES

We compared eating architecture variables derived from precise with those of broad timing methods and examined associations with anthropometric-related and diet-related outcomes.

METHODS

Cross-sectional data came from 3-d diet diaries of 7-y-old children in the Avon Longitudinal Study of Parents and Children. We derived mean size, timing, and frequency of eating, using exact times (precise, n = 4855) and midpoint meal slot times (broad, n = 7285). Intraclass correlation coefficients (ICCs) estimated agreement between methods. Bland-Altman analysis determined mean difference and limits of agreement (LOAs). Correlations (95% CIs) estimated associations between eating architecture variables and anthropometric-related or diet-related traits.

RESULTS

Agreement varied from moderate to excellent for size (ICC: 0.75), last or first time (ICC: 0.80 or 0.58), and frequency (ICC: 0.43) of eating occasions. Broad times underestimated eating frequency (2.2 times/d; LOA: -1, 5) and overestimated size (83 g; LOA: -179, 13), last time (50 min; LOA: -142, 42), intermeal intervals (68 min; LOA: -126, -11), and eating window (49 min; LOA: -161, 63). Directions of eating architecture intercorrelations were consistent regardless of time precision but varied in magnitude, for example, larger eating occasion size correlated with lower eating frequency but was stronger with precise time (rprecise = -0.54; 95% CI: -0.56, -0.52; rbroad = -0.24; 95% CI: -0.27, -0.22). Correlations with anthropometric-related and diet-related outcomes were also directionally consistent.

CONCLUSIONS

Precise timing improves the estimation of eating architecture. Differences in estimation will affect descriptions of children's eating habits and possibly dietary guidance. However, consistent directional associations across timing methods suggest that broad times could provide a pragmatic method for investigating eating architecture associations in large samples.

Evidence on the effectiveness and equity of population-based policies to reduce the burden of type 2 diabetes: a narrative review

There is increasing evidence for the effectiveness of population-based policies to reduce the burden of type 2 diabetes. Yet, there are concerns about the equity effects of some policies, whereby socioeconomically disadvantaged populations are not reached or are adversely affected. There is a lack of knowledge on the effectiveness and equity of policies that are both population based (i.e. targeting both at-risk and low-risk populations) and low agency (i.e. not requiring personal resources to benefit from the policy). In this narrative review, we selected 16 policies that were both population based and low agency and reviewed the evidence on their effectiveness and equity. Substantial evidence suggests that fruit and vegetable subsidies, unhealthy food taxes, mass media campaigns, and school nutrition and physical activity education are effective in promoting healthier lifestyle behaviours. Less evidence was available for mandatory food reformulation, reduced portion sizes, marketing restrictions and restriction of availability and promotion of unhealthy products, although the available evidence suggested that these policies were effective in reducing unhealthy food choices. Effects could rarely be quantified across different studies due to substantial heterogeneity. There is an overall lack of evidence on equity effects of population-based policies, although available studies mostly concluded that the policies had favourable equity effects, with the exception of food-labelling policies. Each of the policies is likely to have a relatively modest effect on population-level diabetes risks, which emphasises the importance of combining different policy measures. Future research should consider the type of evidence needed to demonstrate the real-world effectiveness and equity of population-based diabetes prevention policies.

Associations between child eating behaviors with eating patterns and diet quality in preschool-aged children

Childhood eating behaviors are associated with weight status and laboratory assessments of dietary intake. However, little is known about how eating behaviors relate to the eating patterns and diet quality of children from marginalized populations when assessed in their natural environments. Therefore, we examined the association of food avoidant (e.g., food fussiness and satiety responsiveness) and food approach (e.g., food responsiveness and enjoyment of food) eating behaviors with children's meal size, eating frequency, and diet quality. We analyzed data from 61 predominately low-income Hispanic/Latinx preschool-aged children. Caregivers completed the Childhood Eating Behavior Questionnaire and two 24-h dietary recalls. From the recalls, we calculated meal size, eating frequency, and modified Diet Quality Index Scores (DQIS), and evaluated associations with eating behaviors using multivariable linear models. We also explored the relationship between eating behaviors and DQIS components. Food-avoidant subscales were associated with smaller meals and satiety responsiveness were associated with decreased snack frequency. Food approach subscales were not associated with meal size or eating frequency. Both food-avoidant and food-approach behaviors were associated with components of diet quality and caloric beverages outside of meal and snacks. These findings can inform future research on the relationship between child eating behaviors and dietary intake so that we can develop more tailored and effective interventions to promote healthy eating habits for low-income, Hispanic/Latinx preschool-aged children.

Interindividual variability in appetitive sensations and relationships between appetitive sensations and energy intake

BACKGROUND

Appetitive sensations (AS) are signals that guide eating behaviors. Marked short-term inter-individual variability in AS has been reported but the long-term stability of individual ratings and their dietary implications are not well characterized.

OBJECTIVES

This study explored the stability of inter-individual ratings of hunger, fullness and thirst for 17 weeks; determined the relationships between these sensations, eating patterns and energy intake (EI); as well as the associations between ratings and selected individual characteristics (age, gender, BMI).

METHODS

A 17-week observational study collected hourly appetitive ratings and dietary intake data from 97 (90 completers, 7 partial completers) healthy adults at weeks 1, 9, and 17.

RESULTS

There were marked and stable inter-individual differences over the 17 weeks for hunger (week 1 vs. week 9, r = 0.72 (p < 0.001); week 1 vs. week 17, r = 0.67 (p < 0.001); week 9 vs. week 17, r = 0.77 (p < 0.001)); fullness (week 1 vs. week 9 r = 0.74 (p < 0.001); week 1 vs. week 17, r = 0.71 (p < 0.001); week 9 vs. week 17, r = 0.81 (p < 0.001)); and thirst (week 1 vs. week 9 r = 0.82 (p < 0.001); week 1 vs. week 17, r = 0.81 (p < 0.001); week 9 vs. week 17, r = 0.88 (p < 0.001)). Cross-correlation functions revealed EI and eating pattern exerted stronger effects on AS than the reverse. However, the absolute effect sizes were small. Path analyses also indicated that there were weak relationships between AS and EI. No robust effects of the studied individual characteristics were observed.

CONCLUSION

This study found that acute and chronic sensations of hunger, fullness and thirst are relatively stable within individuals but vary markedly between individuals. In addition, the present data indicate AS are poorly associated with dietary patterns or with EI under conditions of relatively stable energy balance.

The Metabolic Syndrome, a Human Disease

This review focuses on the question of metabolic syndrome (MS) being a complex, but essentially monophyletic, galaxy of associated diseases/disorders, or just a syndrome of related but rather independent pathologies. The human nature of MS (its exceptionality in Nature and its close interdependence with human action and evolution) is presented and discussed. The text also describes the close interdependence of its components, with special emphasis on the description of their interrelations (including their syndromic development and recruitment), as well as their consequences upon energy handling and partition. The main theories on MS's origin and development are presented in relation to hepatic steatosis, type 2 diabetes, and obesity, but encompass most of the MS components described so far. The differential effects of sex and its biological consequences are considered under the light of human social needs and evolution, which are also directly related to MS epidemiology, severity, and relations with senescence. The triggering and maintenance factors of MS are discussed, with especial emphasis on inflammation, a complex process affecting different levels of organization and which is a critical element for MS development. Inflammation is also related to the operation of connective tissue (including the adipose organ) and the widely studied and acknowledged influence of diet. The role of diet composition, including the transcendence of the anaplerotic maintenance of the Krebs cycle from dietary amino acid supply (and its timing), is developed in the context of testosterone and β-estradiol control of the insulin-glycaemia hepatic core system of carbohydrate-triacylglycerol energy handling. The high probability of MS acting as a unique complex biological control system (essentially monophyletic) is presented, together with additional perspectives/considerations on the treatment of this 'very' human disease.

Food portion sizes: trends and drivers in an obesogenic environment

The prevalence of overweight and obesity in children and adults has increased worldwide. A strong environmental factor contributing to the obesity epidemic is food portion size (PS). This review evaluates the current evidence linking food PS to obesity, examines the effects of PS on energy intake (EI), and discusses the drivers of food PS selection. The leading causes of the rise in PS include globalisation, intensive farming methods, the impact of World War II, due to shortage of staple foods, and the notion of 'waste not, want not'. Large PS of energy-dense foods may stimulate overconsumption, leading to high EI levels. However, the studies have not shown a cause-and-effect relationship, due to confounding factors. Important mechanisms explaining the attractiveness of larger PS leading to higher EI levels are value for money, portion distortion, labels on food packaging, and tableware. Consumers depend on external rather than internal PS cues to guide consumption, irrespective of satiety levels. Further research is recommended on food consumption patterns to inform policymakers and provide information and insights about changes in diet.

The effects of eating frequency on changes in body composition and cardiometabolic health in adults: a systematic review with meta-analysis of randomized trials

BACKGROUND

Eating frequency may affect body weight and cardiometabolic health. Intervention trials and observational studies have both indicated that high- and low-frequency eating can be associated with better health outcomes. There are currently no guidelines to inform how to advise healthy adults about how frequently to consume food or beverages.

AIM

To establish whether restricted- (≤ three meals per day) frequency had a superior effect on markers of cardiometabolic health (primary outcome: weight change) compared to unrestricted-eating (≥ four meals per day) frequency in adults.

METHODS

We searched Medline (Ovid), Embase, CINAHL (EBSCO), Cochrane Central Register of Controlled Trials (CENTRAL), CAB Direct and Web of Science Core Collection electronic databases from inception to 7 June 2022 for clinical trials (randomised parallel or cross-over trials) reporting on the effect of high or low-frequency eating on cardiometabolic health (primary outcome: weight change). Trial interventions had to last for at least two weeks, and had to have been conducted in human adults. Bias was assessed using the Cochrane Risk of Bias tool 2.0. Standardized mean differences (SMD) and 95% confidence intervals were calculated for all outcomes. Certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

Seventeen reports covering 16 trials were included in the systematic review. Data from five trials were excluded from meta-analysis due to insufficient reporting. 15 of 16 trials were at high risk of bias. There was very low certainty evidence of no difference between high- and low-frequency eating for weight-change (MD: -0.62 kg, CI95: -2.76 to 1.52 kg, p = 0.57).

CONCLUSIONS

There was no discernible advantage to eating in a high- or low-frequency dietary pattern for cardiometabolic health. We cannot advocate for either restricted- or unrestricted eating frequency to change markers of cardiometabolic health in healthy young to middle-aged adults.

PROTOCOL REGISTRATION

CRD42019137938.

Snacking Behaviours of Australian Young Adults: Secondary Analysis of the MYMeals Cross-Sectional Study

Snacking outside main meals may contribute to the high intakes of discretionary foods (i.e., unhealthful foods) among young adults. This study assessed the snacking behaviours of Australian young adults including the contribution of snacking to energy and nutrient intakes, the main foods consumed, and portion sizes. A secondary analysis of the MYMeals study of adults aged 18-30 years who consumed at least one snack food during the recording period (n = 889) was conducted. All food consumed over 3 consecutive days was recorded using a purpose-designed smartphone app. Snack foods contributed 13.2% of energy, 23.4% of total sugars, and 16.2% of saturated fat. Females consumed more energy (13.8% vs. 12.2%, p = 0.007) and total sugars (25.8% vs. 20.8%, p = 0.009), from snacking than males. Fruit (20.2%), chocolate (9.9%), cake-type desserts (8.4%), sweet biscuits (6.1%), and ice-cream-type desserts (5.6%) were the most frequently consumed snacks by young adults. The median portion sizes for the top five snack foods consumed were fruit-106 g (IQR: 73), chocolate-26 g (IQR: 36), cake-95 g (IQR: 88), sweet biscuits-26 g (IQR: 29), and ice cream-75 g (IQR: 42). The current findings may inform population-wide strategies to encourage healthful snacks such as fruit, inform portion control by individuals, and persuade the food industry to reduce the serving size of discretionary snack foods such as cake.

Role of Portion Size in the Context of a Healthy, Balanced Diet: A Case Study of European Countries

Over the past decades, a generalised increase in food portion sizes has probably contributed to the growing global obesity epidemic. Increasing awareness of appropriate portion sizes could contribute to reversing this trend through better control of calorie intake. In this study, a comparison of standard portion sizes in European countries for various food categories shows a wide variability of their importance for food, nutrient, and energy consumption according to government and institutional websites. On the other hand, the overall averages appear to be largely in line with the values indicated by the Italian Society of Human Nutrition, which is the most comprehensive and detailed document among those evaluated. The exceptions are milk and yoghurt, for which the reference portions in Europe are generally higher, and vegetables and legumes, for which portions are smaller than those reported in the Italian document. Moreover, the portion sizes of staple foods (e.g., pasta and potatoes) vary according to different food traditions. It is reasonable to consider that the creation of harmonised standard reference portions common to the European countries, based on international guidelines and scientific evidence, would significantly contribute to consumers' nutritional education and ability to make informed choices for a healthy diet.

Association between Meal Frequency and Type 2 Diabetes Mellitus in Rural Adults: A Large-Scale Cross-Sectional Study

Diet frequency may potentially influence metabolic health. However, general population-based evidence on the association between meal frequency and type 2 diabetes mellitus (T2DM) remains limited and inconclusive. Thus, this study aimed to investigate the association between meal frequency and T2DM in resource limited area. A total of 29,405 qualified participants were enrolled from the Henan rural cohort study. Data on meal frequency were collected through a validated face-to-face questionnaire survey. Logistic regression models were utilized to explore the association between meal frequency and T2DM. Compared with 21 times per week meal frequency group, the adjusted odds ratios (ORs) and 95% confidence intervals (95%CIs) were 0.75 (0.58, 0.95) and 0.70 (0.54, 0.90) for 16–20 times/week group and 14–15 times/week group, respectively. For the analysis of the three meals, significant associations were only found between dinner frequency and T2DM. Compared with seven times per week dinner group, the ORs (95%CIs) were 0.66 (0.42, 0.99) and 0.51 (0.29, 0.82) for the group with three to six times/week and zero to two times/week. Reduced meal frequency, especially dinner frequency, was associated with lower prevalence of T2DM, which suggests that an appropriate reduction in meal frequency per week may have a role in decreasing the risk of T2DM.

Multisectoral Strategies Needed to Establish Healthy Portion Size Norms That Disincentivize Hyperpalatable, Energy-Dense Foods and Sugary Beverages in Food Environments Linked to Obesity and Diet-Related Chronic Diseases in the United States

Over 40 y, Americans have consumed larger portions of hyperpalatable, energy-dense foods, sugary beverages, and meals prepared at home and away from home, which have contributed to obesity and diet-related chronic diseases in the United States (US). This perspective article explores synergies between the portion size and food matrix effects, and their associated biological, physiological, environmental, and cultural susceptibilities for populations. Thereafter, we describe evidence of US public- and private-sector initiatives to reduce, standardize, and incentivize portion size norms to align with recommended servings to promote a healthy weight for children, adolescents, and adults. Practitioners could use the Individual plus Policy, System, and Environment (I + PSE) Framework to implement multisectoral strategies for the US government, businesses, and civil society organizations to establish healthy portion size norms aligned with servings recommended by the Dietary Guidelines for Americans 2020-2025, and to disincentivize overconsumption of hyperpalatable products to reduce obesity and chronic disease risks.