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In this paper, we explore the role of street vendors in enhancing access to sustainable food, using Mexico City as a case study. Through observational fieldwork, we quantify and spatialize the street food offer of two municipalities, which we compare to food offer in outlets (shops and restaurants). We use Mexican traditional food as a proxy for a sustainable diet. Street vendors represent 55% of the food retailers present in the study area. Over half of street vendors only sell traditional food (against 45% of food outlets), but most sell food to be consumed in moderation (e.g. tacos). A weak statistical correlation suggests that street vendors and food outlets tend to cluster in mixed‐use areas; as such, street vendors' role in the urban food system is mainly to provide an alternative food offer in well‐served areas, rather than providing a food offer in neighbourhoods where the formal offer is scarce. We conclude that street vending is a significant element of Mexico City's urban food environment and increases the availability of traditional food, thus enhancing food sovereignty and contributing to a sustainable food system. Street vending, as an unplanned, traditional daily practice that inadvertently contributes to a sustainable food system, is an example of ‘already existing sustainabilities’, which exploration can provide crucial insights to achieve sustainability transitions. Short This paper presents an empirical study of street vending in two municipalities of Mexico City. Through observational fieldwork, we quantified and spatialized the street food offer, which we compared to food outlets (shops and restaurants), focusing on traditional foods. Street vendors represent 55% of the food retailers present in the study area, and over half of street vendors only sell traditional food (against 45% of food outlets).

Background Regulatory actions are increasingly used to tackle issues such as excessive alcohol or sugar intake, but such actions to reduce sedentary behaviour remain scarce. World Health Organization (WHO) guidelines on sedentary behaviour call for system-wide policies. The Chinese government introduced the world’s first nation-wide multi-setting regulation on multiple types of sedentary behaviour in children and adolescents in July 2021. This regulation restricts when (and for how long) online gaming businesses can provide access to pupils; the amount of homework teachers can assign to pupils according to their year groups; and when tutoring businesses can provide lessons to pupils. We evaluated the effect of this regulation on sedentary behaviour safeguarding pupils. Methods With a natural experiment evaluation design, we used representative surveillance data from 9- to 18-year-old pupils before and after the introduction of the regulation, for longitudinal ( n  = 7,054, matched individuals, primary analysis) and repeated cross-sectional ( n  = 99,947, exploratory analysis) analyses. We analysed pre-post differences for self-reported sedentary behaviour outcomes (total sedentary behaviour time, screen viewing time, electronic device use time, homework time, and out-of-campus learning time) using multilevel models, and explored differences by sex, education stage, residency, and baseline weight status. Results Longitudinal analyses indicated that pupils had reduced their mean total daily sedentary behaviour time by 13.8% (95% confidence interval [CI]: -15.9 to -11.7%, approximately 46 min) and were 1.20 times as likely to meet international daily screen time recommendations (95% CI: 1.01 to 1.32) one month after the introduction of the regulation compared to the reference group (before its introduction). They were on average 2.79 times as likely to meet the regulatory requirement on homework time (95% CI: 2.47 to 3.14) than the reference group and reduced their daily total screen-viewing time by 6.4% (95% CI: -9.6 to -3.3%, approximately 10 min). The positive effects were more pronounced among high-risk groups (secondary school and urban pupils who generally spend more time in sedentary behaviour) than in low-risk groups (primary school and rural pupils who generally spend less time in sedentary behaviour). The exploratory analyses showed comparable findings. Conclusions This regulatory intervention has been effective in reducing total and specific types of sedentary behaviour among Chinese children and adolescents, with the potential to reduce health inequalities. International researchers and policy makers may explore the feasibility and acceptability of implementing regulatory interventions on sedentary behaviour elsewhere.

Promoting traditional diets could potentially reduce the current high rates of non-communicable diseases (NCDs) globally. While the traditional Mexican diet (TMexD) could be specifically promoted in Mexico, a concise definition of the TMexD and evidence of its association with NCDs are needed before its promotion. To evaluate what constitutes this diet pattern, we aimed to systematically review, for the first time, how the TMexD has been described in the literature to date. A secondary aim was to examine whether the TMexD, as described by available definitions, is associated with NCD outcomes. We searched for records describing a whole TMexD up to July 2019 in 12 electronic databases, reference lists, a relevant journal, and by contacting experts on the topic. We reported the results using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. We included 61 records for the definition of the diet and six for the association with NCD outcomes. The food groups characterising the TMexD that were consistently mentioned in all the study subgroups were grains and tubers, legumes, and vegetables; specific foods included maize, beans, chile, squash, tomato, and onion. Other groups also mentioned, although with lesser frequency, were maize products, fruits, beverages, fish and seafood, meats, sweets and sweeteners, and herbs and condiments. Only a few studies reported on the frequency of consumption or the amounts in which these foods were consumed in the TMexD. It was not possible to reach strong conclusions for the association between adherence to the TMexD and NCD outcomes. The TMexD was weakly associated with developing breast cancer, not associated with triglyceride levels, and inconsistently associated with obesity and diabetes outcomes. However, results were limited by the small number of studies (n = 6), of which most were of observational nature and evaluated diets using different TMexD definitions. These findings provide systematically identified evidence of the characteristics of the TMexD. More studies are needed to ascertain the exact quantities by which foods were consumed in the TMexD in order to establish whether this dietary pattern is associated with health and should be promoted within the Mexican population.

This study evaluated the association between adherence to a traditional Mexican diet (TMexD) and obesity, diabetes and CVD-related outcomes in secondary data analysis of the cross-sectional Mexican National Health and Nutrition Survey 2018–2019. Data from 10 180 Mexican adults were included, collected via visits to randomly selected households by trained personnel. Adherence to the TMexD (characterised by mostly plant-based foods like maize, legumes and vegetables) was measured through an adapted version of a recently developed TMexD index, using FFQ data. Outcomes included obesity (anthropometric measurements), diabetes (biomarkers and diagnosis) and CVD (lipid biomarkers, blood pressure, hypertension diagnosis and CVD event diagnosis) variables. Percentage differences and OR for presenting non-communicable disease (NCD)-related outcomes (with 95 % CI) were measured using multiple linear and logistic regression, respectively, adjusted for relevant covariates. Sensitivity analyses were conducted according to sex, excluding people with an NCD diagnosis and using multiple imputation. In fully adjusted models, high, compared with low, TMexD adherence was associated with lower insulin (−9·8 %; 95 % CI (−16·0, −3·3)), LDL-cholesterol (−4·3 %; 95 % CI (−6·9, −1·5)), non-HDL-cholesterol (−3·9 %; 95 % CI (−6·1, −1·7)) and total cholesterol (−3·5 %; 95 % CI (−5·2, −1·8)) concentrations. Men and those with no NCD diagnosis had overall stronger associations. Effect sizes were smaller, and associations weakened in multiple imputation models. No other associations were observed. While results may have been limited due to the adaptation of a previously developed index, the results highlight the potential association between the TMexD and lower insulin and cholesterol concentrations in Mexican adults.

Promoting a traditional Mexican diet (TMexD) could potentially reduce high rates of non-communicable diseases (NCD) and support food sustainability in Mexico. This study aimed to develop an index to assess adherence to the TMexD. A three-round Delphi study was conducted to examine the food groups, specific foods and food-related habits that would constitute a TMexD index. Participants selected the TMexD items using Likert scales, lists of responses, and yes/no questions. Consensus was determined using percentages of agreement, mean values and/or coefficients of variation. Online Delphi study. Seventeen nutrition and food experts in Mexico completed all three rounds. The resulting index (ranging from 0 to 21 points) consisted of 15 food groups, containing 102 individual foods. Food groups included in higher quantities were maize, other grains, legumes, vegetables, fruits, herbs, nuts and seeds, and tubers. Animal foods, vegetable fats and oils, homemade beverages, maize-based dishes, and plain water were also included, but in lower quantities. The food-related habits included were consuming homemade meals, socialising at meals and buying food in local markets. Consensus was reached for all index items apart from quantities of consumption of six food groups (herbs, nuts, grains, tubers, dairy and eggs). Although future research could improve the measures for which consensus was not reached, the TMexD index proposed in this study potentially displays a healthy and sustainable dietary pattern and could be used to examine links between the TMexD and health outcomes in Mexican populations.

Background: Promoting the traditional Mexican diet (TMexD) could potentially reduce the current high rates of non-communicable diseases (NCDs) and support food sustainability in Mexico. However, a concise definition of the TMexD and evidence of its association with NCDs are needed before its promotion. Objective: The aim of this thesis was to: 1) define the association with obesity, diabetes, and cardiovascular diseases (CVDs). Methods: Sixty-one records describing a whole TMexD were systematically reviewed. Then, the systematic review results were used to reach consensus (via a three-round Delphi study with 17 food and nutrition experts) on the food groups, specific foods, and food-related habits constituting a TMexD index. Finally, the association between the developed TMexD index and NCD-related outcomes was evaluated in 10,180 adults from the Mexican National Health and Nutrition Survey 2018-19. Results: The TMexD represents mostly a plant-based diet, characterised by grains, legumes, and vegetables. Other foods recommended include fruits, herbs and condiments, grains, tubers, nuts and seeds, vegetable fats and oils, and plain water; the TMexD also contains moderate amounts of meats, eggs, dairy, calorific beverages, and maize-based dishes. The food-related habits mostly characterising the TMexD were consuming home-made meals, socialising at meals, and buying foods locally. In fully adjusted models, high, compared to low, TMexD adherence was associated (p<0.004) with lower insulin (-9.8%; 95% confidence interval [CI]: -16.0, -3.3), low-density lipoprotein cholesterol (-4.3%; 95% CI -6.9, -1.5), non-high-density lipoprotein cholesterol (-3.9%; 95% CI: -6.1, -1.7), and total cholesterol (-3.5%; 95% CI: -5.2, -1.8) concentrations. No other associations were observed. Conclusions: This thesis presents the first comprehensive index measuring adherence to the TMexD, and found that adhering to the TMexD is associated with reduced risk of some NCD-related outcomes in Mexican adults.