A sustainable diet that meets dietary requirements for health with lower GHGEs can be achieved without eliminating meat or dairy products or increasing the cost to the consumer.

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The concept of a healthy and environmentally sustainable diet is not new, but with increasing concern about future global food security and climate change there is a renewed interest in this topic. Dietary intakes in UK accounts for approximately 20-30 % of total annual greenhouse gas emissions (GHGE), with the greatest contributions coming from high intakes of meat and dairy products. Dietary proposals to help mitigate climate change (i.e. reduce GHGE) have focused on reducing consumption of meat and dairy products, but this must be considered in the context of the whole diet, alongside any possible nutritional consequences for health. Bringing together health and environmental impact of the diet raises the question of whether a healthy diet can also be an environmentally sustainable diet. While recent research showed that it is possible to achieve a realistic diet that meets dietary requirement for health and has lower GHGE, it cannot be assumed that a healthy diet will always have lower GHGE. With different combinations of food it is possible to consume a diet that meets dietary requirements for health, but has high GHGE. It is important to understand what constitutes a sustainable diet, but this then needs to be communicated effectively to try and change well-established dietary intakes of the population. Studies show that understanding of sustainable diets is poor and there are many misconceptions (e.g. the overestimation of the protein requirements for a healthy diet), which could contribute to the barriers towards changing dietary intakes.

Background and objectiveThe increasing prevalence of childhood obesity has led to interest in its prevention, particularly through school-based and family-based interventions in the early years. Most evidence reviews, to date, have focused on individual behaviour change rather than the ‘obesogenic environment’.ObjectiveThis paper reviews the evidence on the influence of the food environment on overweight and obesity in children up to 8 years.Data sourcesElectronic databases (including MEDLINE, EMBASE, Cochrane Controlled Trials Register (CCTR), DARE, CINAHL and Psycho-Info) and reference lists of original studies and reviews were searched for all papers published up to 31 August 2011.Study selectionStudy designs included were either population-based intervention studies or a longitudinal study. Studies were included if the majority of the children studied were under 9 years, if they related to diet and if they focused on prevention rather than treatment in clinical settings.Data extractionData included in the tables were characteristics of participants, aim, and key outcome results. Quality assessment of the selected studies was carried out to identify potential bias and an evidence ranking exercise carried out to prioritise areas for future public health interventions.Data synthesisThirty-five studies (twenty-five intervention studies and ten longitudinal studies) were selected for the review. There was moderately strong evidence to support interventions on food promotion, large portion sizes and sugar-sweetened soft drinks.ConclusionsReducing food promotion to young children, increasing the availability of smaller portions and providing alternatives to sugar-sweetened soft drinks should be considered in obesity prevention programmes aimed at younger children. These environment-level interventions would support individual and family-level behaviour change.

BackgroundAverage population dietary intakes do not reflect the wide diversity of dietary patterns across the population. It is recognised that most people in the UK do not meet dietary recommendations and have diets with a high environmental impact, but changing dietary habits has proved very difficult. The purpose of this study was to investigate the diversity in dietary changes needed to achieve a healthy diet and a healthy diet with lower greenhouse gas emissions (GHGE) (referred to as a sustainable diet) by taking into account each individual’s current diet and then minimising the changes they need to make.MethodsLinear programming was used to construct two new diets for each adult in the UK National Diet and Nutrition Survey (n = 1491) by minimising the changes to their current intake. Stepwise changes were applied until (i) dietary recommendations were achieved and (ii) dietary recommendations and a GHGE target were met. First, gradual changes (≤50 %) were made to the amount of any foods currently eaten. Second, new foods were added to the diet. Third, greater reductions (≤75 %) were made to the amount of any food currently eaten and finally, foods were removed from the diet.ResultsOne person out of 1491 in the sample met all the dietary requirements based on their reported dietary intake. Only 7.5 and 4.6 % of people achieved a healthy diet and a sustainable diet, respectively, by changing the amount of any food they currently ate by up to 50 %. The majority required changes to the amount of each food eaten plus the addition of new foods. Fewer than 5 % had to remove foods they ate to meet recommendations. Sodium proved the most difficult nutrient recommendation to meet. The healthy diets and sustainable diets produced a 15 and 27 % reduction in greenhouse gas emissions respectively.ConclusionsSince healthy diets alone do not produce substantial reductions in greenhouse gas emissions, dietary guidelines need to include recommendations for environmental sustainability. Minimising the shift from current dietary intakes is likely to make dietary change more realistic and achievable.