The aim of this umbrella review was to summarise the evidence from existing systematic reviews on the association between different dietary patterns (DP) and overweight or obesity outcomes in adults.

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and searched the MEDLINE, EMBASE, CINAHL, Cochrane, Scopus, and Web of Science for systematic reviews reporting on DP and weight gain or overweight/obesity outcomes.

We identified 16 systematic reviews with 143 unique studies published between 2001 and 2019. Overall quality scores ranged from 4 to 10. Six reviews in 2/11 cohort and 6/19 cross-sectional studies reported (statistically significant) decreased OR for obesity (range: 0·53 to 0·73 and 0·35 to 0·88, respectively) associated with the Mediterranean diet. Five reviews in 5/15 cohort and 10/45 cross-sectional studies reported an inverse association between diet quality and weight gain or BMI (β range: –1·3 to –0·09). Two reviews in 1/3 cohort and 1/2 cross-sectional studies reported a decreased risk of obesity (OR = 0·76) and weight gain (OR = 0·26), respectively, with fruit and vegetable intake. Five reviews of mixed DP in 3/40 cross-sectional studies reported an increased prevalence of obesity (OR = 1·19) or abdominal obesity (OR range: 1·07 to 1·27) with the Korean diet pattern.

Our umbrella review confirms the hypothesis that Mediterranean-type DP reduce the risk of obesity in adults. Although population-specific evidence of effective interventions is needed, characteristics of Mediterranean-type DP are important considerations for national obesity prevention strategies.

To estimate the burden of excess weight in Brazilian adolescents.

Systematic review with meta-analysis.

We searched the literature in four databases (MEDLINE/PubMed, EMBASE, SciELO and LILACS). Studies were included if they had cross-sectional or cohort design and enrolled Brazilian adolescents. Studies based on self-reported measures were excluded. Random effect models were used to calculate prevalence estimates and their 95 % CI.

Brazilian adolescents (10 to 19 years old).

One hundred and fifty-one studies were included. Trend analyses showed a significant increase in the prevalence of excess weight in the last decades: 8·2 % (95 % CI 7·7, 8·7) until year 2000, 18·9 (95 % CI 14·7, 23·2) from 2000 to 2009, and 25·1 % (95 % CI 23·4, 26·8) in 2010 and after. A similar temporal pattern was observed in the prevalence of overweight and obesity separately. In sensitivity analyses, lower prevalence of excess weight was found in older adolescents and those defined using International Obesity Task Force cut-off points. The Southeast and South regions had the highest prevalence of excess weight, overweight and obesity. No significant difference in prevalence by sex was found, except for studies before the year 2000.

The prevalence of overweight and obesity in Brazilian adolescents is high and continues to rise. Public policies on an individual level and targeting modifications in the obesogenic environment are necessary.

The meta-analysis was conducted to test the link between pancreatic cancer (PC) risk and dietary inflammatory index (DII®) score.

Systematic review and meta-analysis.

We searched PubMed, Embase, Web of Science and the Cochrane Library up to 22 November 2020 to identify the relevant studies. Studies that reported the risk estimates and the corresponding 95 % CI for the DII category and PC risk were included. The effect sizes were pooled using the random-effects model. Dose–response analysis was conducted where possible.

Two prospective cohort studies of 634 705 participants (3152 incident cases), and four case–control studies of 2737 cases and 4861 controls.

Overall, the pooled risk ratio (RR) indicated that individuals in the highest category compared with the lowest category had an increased PC risk (RR = 1·45; 95 % CI 1·11, 1·90; P = 0·006). Meanwhile, significant heterogeneity was also revealed. The dose–response meta-analysis indicated that a 1-unit increase in the DII score was associated with the PC risk (RR = 1·08; 95 % CI 1·002, 1·166; P = 0·045; I2 = 94·1 %, P < 0·001). Nonlinear result showed an increased risk of moving from fewer to more inflammatory borders with increasing DII score (Pnonlinearity = 0·003; I2 = 76·5 %, P < 0·001). Subgroup analyses found that significant positive association between PC risk and DII score appeared to be in case–control studies (RR = 1·70; 95 % CI 1·16, 2·50; P = 0·007) and studies with ≤ 31 DII components (RR = 1·76; 95 % CI 1·14, 2·72; P = 0·011).

These findings suggested dietary habits with high inflammatory features (high DII score) might increase PC risk.

To examine the literature and identify main themes, methods and results of studies concerning food and nutrition addressed in research on transgender populations.

A systematic review conducted through July 2020 in the MedLine/PubMed, Scopus and Web of Science databases.

Of the 778 studies identified in the databases, we selected thirty-seven. The studies were recent, most of them published after 2015, being produced in Global North countries. The most often used study design was cross-sectional; the least frequently used study design was ethnographic. Body image and weight control were predominant themes (n 25), followed by food and nutrition security (n 5), nutritional status (n 5), nutritional health assistance (n 1) and emic visions of healthy eating (n 1).

The transgender community presents body, food and nutritional relationships traversed by its unique gender experience, which challenges dietary and nutritional recommendations based on the traditional division by sex (male and female). We need to complete the lacking research and understand contexts in the Global South, strategically investing in exploratory-ethnographic research, to develop categories of analysis and recommendations that consider the transgender experience.

To estimate the prevalence of anaemia in Brazilian children up to 83·9 months old.

Systematic review and meta-analysis, using databases PubMed, Scopus, SciELO, Lilacs, Google Scholar, Periódicos Capes, Arca, Biblioteca Virtual em Saúde, Microsoft Academic Search and Cochrane Library using search terms: anaemia, prevalence, child and Brazil. PROSPERO Registration number: CRD42020208818.

Cross-sectional, cohort, case–control and intervention studies published between 2007 and 2020 were searched, excluding those who assessed children with an illness or chronic condition. The main outcome was anaemia prevalence. Random effects models based on the inverse variance method were used to estimate pooled prevalence measures. Sensitivity analyses removed studies with high contribution to overall heterogeneity.

From 6790 first screened, 134 eligible studies were included, totalling 46 978 children aged zero to 83·9 months analysed, with adequate regions representativeness.

Pooled prevalence of anaemia was 33 % (95 % CI 30, 35). Sensitivity analyses showed that withdrawal of studies that contributed to high heterogeneity did not influence national average prevalence.

Childhood anaemia is still a serious public health problem in Brazil, exposing 33 % of Brazilian children to the anaemia repercussions. The main limitation of the study is the estimation of national prevalence based on local surveys, but a large number of studies were included, with representation in all regions of the country, giving strength to the results. In Brazil, more public policies are needed to promote supplementation, fortification and access to healthy eating to reduce the high level of anaemia among children.

Vitamin A (VA) deficiency, more common in low- and middle-income countries (LMIC) secondary to malnutrition, is associated with increased morbidity and mortality. The prevalence and impact of VA deficiency in high-income countries (HIC) where chronic conditions may predispose is less well understood.

Interpretation of serum retinol may be affected by inflammation, so C-reactive protein (CRP) levels were sought. Binary logistic regression and generalised estimating equations were performed to review the relationship between CRP and VA.

We examined the scale of low and deficient VA status in our tertiary University Teaching Hospital (HIC).

Patients undergoing serum retinol concentrations 2012–2016 were identified from laboratory records, and records examined.

Totally, 628 assays were requested, with eighty-two patients VA low (0·7–0·99 Umol/l) or deficient (<0·7 Umol/l). Sixteen patients were symptomatic (fifteen deficient), predominantly visual. Only one symptomatic patient’s VA deficiency was secondary to poor intake. Other symptomatic patients had chronic illnesses resulting in malabsorption. The incidence of a low VA level increases significantly with a raised CRP.

The majority of patients tested either were replete or likely to have abnormal VA levels due to concomitant inflammation. A minority of patients had signs and symptoms of VA deficiency and was a cause of significant morbidity, but aetiology differs from LMIC, overwhelmingly malabsorption, most commonly secondary to surgery or hepatobiliary disease. A correlation between inflammation and low VA levels exists, which raises the possibility that requesting a VA level in an asymptomatic patient with active inflammation may be of questionable benefit.

Hispanic adults in the USA tend to have a disproportionate prevalence of metabolic syndrome (MetS) as compared to other races.

We examined whether the association between acculturation and MetS and its components are mediated by the intake of fruit in Hispanics.

Data from the National Health and Nutrition Examination Surveys 2009–2016 were used in this study.

A total of 2078 Hispanics aged ≥ 20 years were included in this analysis.

The mediating role of total fruit intake was assessed using multivariable-adjusted logistic structural equation models with the bootstrapping method by estimating indirect (IE) and direct (DE) effects from acculturation to MetS. High acculturation was associated with increased odds of MetS (adjusted OR = 1·20, 95 % CI 1·04, 1·39), central obesity (OR = 1·24, 95 % CI 1·07, 1·44) and high blood pressure (OR = 1·16, 95 % CI 1·02, 1·32) among Hispanic adults. Total fruits intake partially mediated the associations of acculturation with MetS (ORIE = 1·02, 95 % CI 1·00, 1·03) and central obesity (ORIE = 1·02, 95 % CI 1·00, 1·03), whereas fully mediated the association between acculturation and high blood pressure (ORIE = 1·03, 95 % CI 1·01, 1·06). Moreover, intake of total fruits fully mediated the acculturation–MetS association among Mexican Americans (ORIE = 1·02, 95 % CI 1·00, 1·05).

Our findings suggested that increasing fruit consumption may reduce the impact of high acculturation on MetS development in Hispanic adults. Further studies are needed to confirm these findings.

To characterise the food environment of public hospitals in a Brazilian metropolis.

A cross-sectional study involving the audit of mini-kitchens, non-commercial food services, commercial food services and vending machines within hospitals and interviews with workers and managers. Environmental dimensions assessed included: availability, accessibility, affordability, convenience, nutrition information, promotion and advertising, infrastructure for food and ambience, in addition to decisions-level aspects.

Rio de Janeiro, Brazil.

24 public hospitals in the municipal health network.

Of the hospitals assessed, 92·0 % had a non-commercial food service, 87·5 % had mini-kitchens (facilities to consume food taken from home), 37·5 % had commercial food services and 25·0 % had vending machines. Mini-kitchens were available in most but not all hospitals, a key facility given that few commercial or non-commercial food services were open 24 h a day. The food availability in the hospitals surveyed did not promote healthy eating. A wide variety of ultra-processed foods and drinks was found and advertising promoting their consumption, even in non-commercial food services with menus planned by nutritionists. Water filters/fountains were present in around 50 % of mini-kitchens and non-commercial food services but were unavailable in commercial food services. According to workers interviewed, the temperature of the environment was the worst-rated aspect of mini-kitchens, non-commercial food services and commercial food services. Nutrition service managers reported little involvement in producing biddings and proposals for hiring outside companies to run non-commercial food services or commercial food services.

The food environment of the hospitals studied did not promote healthy eating habits.

To understand the key mechanisms that support healthy dietary habits promoted by fruit and vegetable (F&V) box schemes, testing relevant behaviour change triggers identified under the COM-B model in an evaluation research study of a Portuguese F&V box scheme (PROVE).

Correlation study with a post-test-only non-equivalent group design based on survey data. The mechanisms underpinning the differences between subscribers and non-subscribers are operationalised as mediation effects. Data availability, theoretical relevance and empirical validation supported the selection and testing of four potential mediators for the effects of subscribing to the box scheme on F&V consumption. These estimations derive from the coefficients of a structural equation model combined with the product coefficient approach and Sobel test.

The study is part of a wider evaluation study on the impact of the PROVE box scheme on sustainability, health and equity.

A sample of PROVE box subscribers (n 294) was compared with a matched subsample of non-subscribers (n 571) in a nationally representative survey.

Subscribing to the PROVE box correlates with an increased probability of eating at least five portions of F&V, irrespective of differences in age, education and perceived economic difficulties. Diet quality perceptions, and more robustly, the strength of meal habits and household availability were identified as relevant mediators.

The subscription to an F&V box scheme is connected with proximal context that enables the consumption of F&V by ensuring more readily available F&V and better situational conditions associated with healthier meal habits.

To assess the extent to which mandatory Guidelines to improve the school food environment were being implemented in Costa Rican high schools and to explore the perspectives of key policy actors towards the Guidelines.

Semi-structured interviews and site observations. Interviews were recorded, transcribed verbatim and imported to NVivo 12 for analysis. Inductive and deductive themes were identified, and elements of the RE-AIM framework and the social process framework were used when classifying these themes.

Sixteen public high schools in San José, Costa Rica.

High school principal and kiosk concessionaires

Products that did not adhere to the Guidelines were still widely available in schools, and amongst the most prevalent challenges to implementation that emerged from our interviews, were a lack of understanding of the policy content, a lack of monitoring and accountability, and competing values amongst actors which affected their views on the role that the school must have in offering a healthy food environment.

Most products offered in high schools did not meet the criteria required by the mandatory Guidelines, and several contextual factors were found to influence implementation. Strengthening the implementation of the Costa Rican Guidelines will require further actions at the governmental and school levels.

To assess the association between the consumption of school meals offered by the National School Feeding Program (PNAE, in the Portuguese acronym) and the diet quality of adolescents aged 11 to 19 years from Brazilian public schools.

Cross-sectional.

Public schools in Brazil.

A sample of 12 260 adolescents aged 11 to 19 years from 2015 National School Health Survey. High consumption of PNAE school meals were considered when the adolescents consumed school meals 5 d/week. Food consumption data were obtained from a 7-d FFQ and converted into three diet quality assessment scores, namely (1) consumption of healthy foods; (2) consumption of unhealthy foods and (3) overall diet quality. Crude and adjusted linear regression models were used to test the association between high consumption to school meals (daily consumption) and each diet quality score.

More than one-fifth of the adolescents (21·5 %) reported high consumption of school meals. High consumption of school meals was directly associated with the score of the overall diet quality (adjusted coefficient = 0·18; 95 % CI 0·07, 0·30) and healthy food consumption (adjusted coefficient = 0·42; 95 % CI 0·26, 0·57), and inversely associated with the unhealthy food consumption score (adjusted coefficient = −0·23; 95 % CI −0·35, −0·10).

Our results showed that the consumption of PNAE meals may contribute to healthy eating promotion in Brazil.

This study aimed to develop a conceptual framework of the process of food-based dietary guidelines (FBDG) implementation and analyse Brazil’s employed measures to implement dietary guidelines for the Brazilian population (2014).

Qualitative research.

Aiming to develop the conceptual framework, a literature review on FBDG implementation was carried out. Both documents scoped within the macropolitical sphere and scientific articles were reviewed. In the case study, measures took in Brazil were identified through a search on institutional websites and technical management reports of government sectors were responsible for FBDG implementation in the country.

This study does not involve humans.

The new conceptual framework frames FBDG implementation as a part of a larger set of intersectoral public policies to promote healthy eating and highlights two main implementation ways: educational materials and public policies. Brazil has a range of policies to promote healthy eating guided by the perspective of food as a right. Most of the implemented measures focussed on the concept of ‘FBDG as educational materials,’ although the recommendations have also been implemented in public policies.

The FBDG implementation should be carried out in an integrated manner with multi-sector involvement. The Brazilian’s case analysis can be helpful to decision makers in food policy across the globe be inspired by the Brazilian efforts, considering that the Brazilian FBDG was one of the firsts to have adopted a multidimensional paradigm of healthy eating, including diet sustainability.

To estimate the impact of opting into the community eligibility provision (CEP) on school meal participation among students in Texas.

A quasi-experimental design using a two-way fixed effects panel difference-in-difference model and the variation in adoption timing to estimate the impact of opting into CEP on student breakfast and lunch participation in eligible, ever-adopting schools.

All public and charter K-12 schools in Texas participating in national school meals (breakfast and/or lunch) from 2013 to 2019 who are eligible for the CEP program in at least 1 year and choose to opt into the program in at least 1 year (n 2797 unique schools and 16 103 school-years).

School-level administrative data from the Texas Department of Agriculture on meal counts, enrollment and summary characteristics of students merged with district-level educational and socio-demographic data from the Texas Education Authority.

We find opting into CEP increased school breakfast participation by 4·59 percentage points (P < 0·001) and lunch participation by 4·32 percentage points (P < 0·001), on average. The effect is slightly larger (4·64 and 4·61, respectively) and still statistically significant when excluding summer months.

Our findings suggest that opting into CEP modestly increases school meal participation in Texas, with a similar impact on breakfast and lunch.

This article examined whether participation in the Supplemental Nutrition Assistance Program (SNAP) produced changes to adult and child health and health care utilisation during a period of economic recession.

Instrumental variables analysis relying on variation in state SNAP policies to isolate exogenous variation in household SNAP participation.

Nationally representative data on child and adult health from the 2008 to 2013 National Health Interview Survey.

Participants were 92 237 adults and 45 469 children who were either eligible for SNAP based on household income and state eligibility rules or were low income but not eligible for SNAP benefits.

For adults, SNAP participation increased the probability of reporting very good or excellent health, and for both adults and children, reduced needing but having to go without dental care or eyeglasses. The size of these benefits was especially pronounced for children. However, SNAP participation increased the probability of needing but not being able to afford prescription medicine, and increased psychological distress for adults and behavioural problems for children under age 10.

SNAP’s benefits for adult health and improved access to dental and vision care for adults and children suggest benefits from the program’s expansions during the current COVID-induced crisis. Predicted negative effects of SNAP participation suggest the need for attention to program and benefit structure to avoid harm and the need for continued research to explore the causal effects of program participation.

The North Carolina Legislature appropriated funds in 2016–2019 for the Healthy Food Small Retailer Program (HFSRP), providing small retailers located in food deserts with equipment to stock nutrient-dense foods and beverages. The study aimed to: (1) examine factors facilitating and constraining implementation of, and participation in, the HFSRP from the perspective of storeowners and (2) measure and evaluate the impact and effectiveness of investment in the HFSRP.

The current analysis uses both qualitative and quantitative assessments of storeowner perceptions and store outcomes, as well as two innovative measures of policy investment effectiveness. Qualitative semi-structured interviews and descriptive quantitative approaches, including monthly financial reports and activity forms, and end-of-programme evaluations were collected from participating HFSRP storeowners.

Eight corner stores in North Carolina that participated in the two cohorts (2016–2018; 2017–2019) of the HFSRP.

Owners of corner stores participating in the HFSRP.

All storeowners reported that the HFSRP benefitted their stores. In addition, the HFSRP had a positive impact on sales across each category of healthy food products. Storeowners reported that benefits would be enhanced with adjustments to programme administration and support. Specific suggestions included additional information regarding which healthy foods and beverages to stock; inventory management; handling of perishable produce; product display; modified reporting requirements and a more efficient process of delivering and maintaining equipment.

All storeowners reported several benefits of the HFSRP and would recommend that other storeowners participate. The barriers and challenges they reported inform potential approaches to ensuring success and sustainability of the HFSRP and similar initiatives underway in other jurisdictions.

A sustainable diet is an affordable diet with low environmental impact, high food security and sufficient healthiness. The present study aimed to assess the correlation between the socio-economic status of households and a sustainable diet.

The food basket and socio-economic data of Iranian households were evaluated during 2016–2018. The households were classified based on the sustainability of their diet by determining the dietary carbon footprint, dietary water footprint, lower dietary costs of the household than the median and a higher dietary quality index than the median. Logistic regression was used with four models to calculate the OR of a more sustainable diet as the dependent variable regarding the different quartiles of socio-economic status (SES) as the independent variable.

Iran.

Iranian households (n 102 303), nationally representative, were studied.

Lower SES was associated with the higher OR of a sustainable diet (OR: 0·90; (95 % CI 0·87, 0·91)). Higher quartiles of SES compared with the lower SES group indicated the higher energy intake and consumption of more dairies, meat, poultry, fish, eggs, legumes, nuts and fruits, as well as the lower intake of bread, cereal, rice and pasta.

In countries such as Iran, where nutrition transition occurs rapidly, better economic and social levels in the populations with a higher SES are associated with increased energy intake and higher consumption of animal-based foods, which decreases sustainable diets compared with the groups with a lower SES.