Background: School meals hold considerable potential to shape children's diets and reduce food-related greenhouse gas emissions (GHGE)-in the short and long term. This study applied linear optimization to develop a GHGE-reduced, nutritionally adequate, and affordable school lunch menu. The effects on food waste, consumption and pupils' satisfaction with the meals were evaluated. Methods: A pre-post design was employed to assess the effects of implementing an optimized lunch menu on daily food waste, consumption, and pupils' school meal satisfaction in three schools (grades 0-9) from one Swedish municipality. A food list containing amounts, prices, nutrient content, and GHGE-values of all foods used for a previously served (baseline) four-week lunch menu was created. Using linear programming, this food list was optimized for minimum deviation and constrained to ensure nutritional adequacy and a reduced climate impact. The optimized food list was developed into a new (intervention) four-week lunch menu by a professional meal planner, following the baseline menu as closely as possible. The baseline and intervention menus were served for four weeks, respectively, with a two week break in between. Prepared, wasted and leftover food were weighed daily by the school kitchen staff during both periods. Interrupted time series analysis assessed mean and slope differences in daily food waste and consumption between the two periods. School lunch satisfaction was assessed with an online questionnaire at baseline and during the intervention. Results: Optimization resulted in a food list that was 40% lower in GHGE, met all nutrient recommendations for school meals, and cost 11% less compared to baseline. The intervention menu was served as planned, with only minor changes required (for practical reasons). Plate waste, serving waste, consumption and school lunch satisfaction did not differ significantly from baseline, in any of the schools. Conclusions: The findings demonstrate that school meals can successfully be improved regarding health and environmental sustainability using linear optimization, without negative effects on food waste, consumption or cost. This approach offers the necessary flexibility to tailor menus towards different priorities and could therefore be transferred to other types of meal services.

Objective: Overweight has been increasing in several developed countries over the last few decades. No update information on the issue is available for Italy. Design and setting: We conducted a computer assisted personal in-house interview survey in March-April 2004, on a sample of 2932 Italian individuals (1407 men and 1525 women) aged 18 years or over, representative of the general adult Italian population. Information on weight and height was self-reported. Results: Overall, 3.4% of the Italian adult population were underweight (o18.5 kg/m 2 , 0.9% of men and 5.8% of women), 31.3% were overweight (25.0-29.9 kg/m 2 , 38.4% of men, 24.7% of women), and 8.2% were obese (X30.0 kg/m 2 , 7.4% of men and 8.9% of women). Overweight or obesity was reported by 14.2% of subjects aged 18-24 years (20.6% of men and 7.6% of women). The highest proportions of overweight and obese subjects were in the 45-64 year age group for men (51.4% overweight, 10.0% obese) and in the X65 year age group for women (38.8% overweight, 13.8% obese). Age-and sex-standardised prevalence of overweight or obesity was 36.0% for more educated subjects, and 54.0% for less educated ones. It was 32.3% in northern, 44.3% in central and 47.0% in southern Italy. Overweight increased from 1983 to the early 1990s, and levelled off thereafter. Prevalence of obesity remained around 8-9% across the last 20 years. Conclusions: Trends of overweight and obesity in Italy are more favourable than in several developed countries. Still, approximately 15 million of Italian adults are overweight and 4 million obese.

OBJETIVO: Analisar os fatores de risco associados à obesidade e sobrepeso em crianças de ambos os sexos em idade escolar. MÉTODO: Pesquisa do tipo survey realizada com 162 crianças matriculadas no ensino fundamental I de uma escola pública da cidade de São Paulo. A coleta de dados foi obtida por meio de um formulário contendo dados antropométricos e sobre os hábitos alimentares. Os dados foram analisados por meio de estatística inferencial. RESULTADOS: As crianças com sobrepeso e obesidade representaram 38,2% da amostra. Os fatores de risco associados relevantes foram o consumo de refrigerantes e a prática de atividade física. CONCLUSÃO: O estudo evidencia a presença de sobrepeso e obesidade entre as crianças estudadas, confirmando a tendência mundial de mudança no perfil nutricional da população em geral.

Objective:School lunches have potential to foster healthy diets in all children, but data on their importance are relatively scarce. The current study aimed to describe the dietary intake from school lunches by sex and school grade, and to assess how the daily intake, school lunch intake and the daily intake provided by lunch differ by sex and parental education.Design:Cross-sectional. All foods and drinks consumed for 1–3 weekdays were self-reported. Energy, absolute and energy-adjusted intakes of nutrients and food groups were calculated per weekday and per school lunch. Mixed-effects linear models assessed sociodemographic differences in dietary intakes. Nutrient and energy density at lunch and during the rest of the day were compared.Setting:Seventy-nine Swedish primary schools.Participants:Pupils in grades 5 and 8 (N 2002), nationally representative.Results:Lunch provided around half of daily vegetable intake and two-thirds of daily fish intake. Nutrient density was higher and energy density lower at lunch compared with the rest of the day (P < 0·001). Boys had greater energy-adjusted intakes of red/processed meat and lower intakes of vegetables and dietary fibre compared with girls (P < 0·001), overall and at lunch. Daily energy-adjusted intakes of most nutrients/food groups were lower for pupils of lower-educated parents compared with pupils of parents with higher education, but at lunch, only Fe and fibre intakes were significantly lower in this group.Conclusions:School lunches are making a positive contribution to the diets of Swedish children and may mitigate well-established sex differences and social inequalities in dietary intake.

There is great potential for reducing greenhouse gas emissions (GHGE) from public-sector meals. This paper aimed to develop a strategy for reducing GHGE in the Swedish school food supply while ensuring nutritional adequacy, affordability, and cultural acceptability. Amounts, prices and GHGE-values for all foods and drinks supplied to three schools over one year were gathered. The amounts were optimized by linear programming. Four nutritionally adequate models were developed: Model 1 minimized GHGE while constraining the relative deviation (RD) from the observed food supply, Model 2 minimized total RD while imposing stepwise GHGE reductions, Model 3 additionally constrained RD for individual foods to an upper and lower limit, and Model 4 further controlled how pair-wise ratios of 15 food groups could deviate. Models 1 and 2 reduced GHGE by up to 95% but omitted entire food categories or increased the supply of some individual foods by more than 800% and were deemed unfeasible. Model 3 reduced GHGE by up to 60%, excluded no foods, avoided high RDs of individual foods, but resulted in large changes in food-group ratios. Model 4 limited the changes in food-group ratios but resulted in a higher number of foods deviating from the observed supply and limited the potential of reducing GHGE in one school to 20%. Cost was reduced in almost all solutions. An omnivorous, nutritionally adequate, and affordable school food supply with considerably lower GHGE is achievable with moderate changes to the observed food supply; i.e., with Models 3 and 4. Trade-offs will always have to be made between achieving GHGE reductions and preserving similarity to the current supply.

Low-carbon diets can counteract climate change and promote health if they are nutritionally adequate, affordable and culturally acceptable. This study aimed at developing sustainable diets and to compare these with the EAT-Lancet diet. The Swedish national dietary survey Riksmaten Adolescents 2016–17 was used as the baseline. Diets were optimized using linear programming for four dietary patterns: omnivores, pescatarians, vegetarians and vegans. The deviation from the baseline Riksmaten diet was minimized for all optimized diets while fulfilling nutrient and climate footprint constraints. Constraining the diet-related carbon dioxide equivalents of omnivores to 1.57 kg/day resulted in a diet associated with a reduction of meat, dairy products, and processed foods and an increase in potatoes, pulses, eggs and seafood. Climate-friendly, nutritionally adequate diets for pescatarians, vegetarians and vegans contained fewer foods and included considerable amounts of fortified dairy and meat substitutes. The optimized diets did not align very well with the food-group pattern of the EAT-Lancet diet. These findings suggest how to design future diets that are climate-friendly, nutritionally adequate, affordable, and culturally acceptable for Swedish adolescents with different dietary patterns. The discrepancies with the EAT diet indicate that the cultural dietary context is likely to play an important role in characterizing sustainable diets for specific populations.

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There is great potential for reducing greenhouse gas emissions (GHGE) from public sector meals. This paper aimed to develop a strategy for reducing GHGE in the Swedish school food supply without compromising nutritional adequacy, affordability, and cultural acceptability. Amounts, prices and GHGE-values for all foods and drinks supplied to three schools over one year were gathered. The amounts were optimized by linear programming. Four nutritionally adequate models were developed: Model 1 minimized GHGE while constraining relative deviation (RD) from observed food supply; Model 2 minimized total RD while imposing stepwise GHGE reductions; Model 3 additionally constrained RD for individual foods to an upper and lower limit; and Model 4 further controlled how ratios between food groups could deviate. Models 1 and 2 reduced GHGE by up to 95% but omitted entire food categories or increased the supply of some individual foods by more than 800% and were deemed unfeasible. Model 3 reduced GHGE by up to 60%, excluded no foods, avoided high RDs of individual foods, but resulted in large changes in food group ratios. Model 4 limited changes in food group ratios but resulted in a higher number of foods deviating from the observed supply and limited the potential of reducing GHGE. Cost was reduced in almost all solutions. An omnivorous, nutritionally adequate, and affordable school food supply, with considerably lower GHGE is achievable with moderate changes to the observed food supply. Trade-offs will always have to be made between achieving GHGE reductions and preserving similarity to the current supply.