Table 1.

Characteristics of interventions included in this review, where school lunch menus were designed to be more sustainable.

Author, Year and Location	Intervention Category	Sample Characteristics/Data Source	Intervention	Intervention Duration	Evaluation Design	Intervention Group	Comparison or Control Group	Outcome(s) Related to Sustainable School Food Systems	Main Findings
1. Poinsot et al., 2022 [36] France	School lunch menu designed to be more sustainable	Primary school lunch menus from schools in France where school meals are required to be made up of four or five components (i.e., a starter and/or dessert, a protein dish, a side dish and a dairy product).	School lunch menu optimised by considering four ‘trade-offs’: (1) Reducing the number of meal components; (2) Compliance with national school nutrition guidelines; (3) Increasing the number of vegetarian meals; (4) Avoiding ruminant meat.	N/A	Pre–post (Modelling study)	Optimised menu (four trade-offs compared)	Standard menu	Greenhouse gas emissions (% reduction in kg CO2 eq per meal)	Best pre–post reduction from more vegetarian meals (25% reduction).
2. Colombo et al., 2021 [33] Sweden	School lunch menu designed to be more sustainable	Primary school kitchen staff and pupils (aged 10–15) from schools in Sweden where the same lunch menu is provided to all schools, but each school chef has some degree of freedom to adapt menus to match preferences of their pupils.	Implementation of menu optimised to be 40% lower in greenhouse gas emissions.	4 weeks	Qualitative study: Focus groups (n = 9)	29 primary school children and 13 kitchen staff	N/A	Barriers and levers to successful implementation of sustainable men	Experiences with the menu: -Variations in how it was received; -A challenging experience to work with the new menu. The meaning of sustainability: -A broad and varied understanding of diet and sustainability; -Diet sustainability important but hard to realise. Plant-based acceptance: -Decisive role of taste, appearance, smell and recognition; -Habits, peer pressure and fears challenging acceptance. Opportunities to increase plant-based eating: -Focusing on familiar foods; -Increasing exposure, normalisation and motivation. -Gradual and realistic changes: Need for supportive environment: -More knowledge, resources and inspiration; -Increased stakeholder involvement.
3. Perez-Neira et al., 2021 [27] Spain	School lunch menu designed to be more sustainable	School lunch menu data from pre-schools and primary schools in Spain. Lunch menus developed by the local government school canteen network, with catering service provided by local kitchens.	School lunch menu optimised to simulate compliance with new agro-ecological policies on: (1) How products are produced; (2) Where products are produced and consumed; (3) When and how the products are consumed; (4) What products are consumed.	N/A	Pre–post (Modelling study)	Optimised menus	Baseline menus	Total GHG emission (% reduction in kg of CO2-eq per meal)	Pre: 1.36 kg of CO2-eq per meal. Post: 13.4% reduction if current trajectory followed but could rise to 40.6% if transformation advanced.
4. Batlle-Bayer et al., 2021 [29] Spain	School lunch menu designed to be more sustainable	High school lunch menus from schools in Spain, where meals consisted of two courses, dessert and bread.	School lunch menus optimised to simulate transition to low carbon meals using Nexus approach—considering following measures: (1) Blue water footprint (BWF); (2) Primary energy demand (PED); (3) Land use (LU); (4) Global warming potential (GWP).	N/A	Pre–post (Modelling study)	Optimised menu	Standard menu	% reduction in environmental impact (based on Nexus approach measures)	Optimised menu had the following reductions: 60% BWP, 46% PED, 48% LU and 53% GWP.
5. Colombo et al., 2020 [34] Sweden	School lunch menu designed to be more sustainable	Primary schools in Sweden, where children had two daily meals to choose from.	Implementation of menu optimised to be 40% lower in greenhouse gas emissions.	4 weeks	Pre–post	3 schools (n = 1635 pupils)	No comparison group	(1) Food waste (g/pupil); (2) Consumption (g/pupil); (3) School meal satisfaction (pre-post questionnaire).	(1) No pre–post difference in any of the participating schools; (2) No pre–post difference in any of the participating schools; (3) No pre–post difference in any of the participating schools.
6. Blondin et al., 2022 [45] USA	School lunch menu designed to be more sustainable	Schools from large urban school district in the USA, where one entrée was offered per day.	Meatless Mondays	One menu cycle (2–4 weeks)	Pre–post	One school district	No comparison group	(1) GHG emissions kg CO2-eq (per entree offered on a Monday and per entree averaged over week); (2) Water resources (litres).	(1) Significant reduction for pre–post meals offered on a Monday (0.95 vs. 0.25 kg CO2-eq), but no pre–post difference for meals averaged over week; (2) No significant differences.
7. Elinder et al., 2020 [35] Sweden	School lunch menu designed to be more sustainable	Primary school pupils from schools in Sweden serving a four-week menu plan (including 2–3 dishes/day over a period of 20 weekdays).	Implementation of a menu optimised to be 28% lower in greenhouse gas emissions.	4 weeks	Pre–post	4 primary schools (each with 360–660 pupils)	No comparator group	(1) Food consumption (g/pupil); (2) Food waste (g/pupil).	(1) No significant changes; (2) Plate waste significantly increased in one school (16 g/pupil to 21 g/pupil), but no significant changes overall.
8. Martinez et al., 2020 [28] Spain	School lunch menu designed to be more sustainable	Primary school lunch menus from schools in Spain designed following Spanish schools’ dietary guidelines.	School lunch menus optimised to reduce their carbon footprint considering food production, transportation and cooking. Six scenarios were considered: (1) Without dairy and legumes; (2) Without meat; (3) Without fish; (4) Without eggs; (5) Hypocaloric menu; (6) Astringent menu (menu designed to avoid causing stomach upsets using cooking techniques such as boiling and baking (e.g., boiled vegetables and chicken breast)).	N/A	Pre–post (Modelling study)	Optimised menu	Standard menu	Carbon footprint (kg CO2 eq.person/monthly).	Pre: 24.39 kg CO2 eq.person/monthly. Post: Greatest reductions from astringent menu (14.77 kg CO2 eq.person/monthly) and menu without meat (17.11 kg CO2 eq.person/monthly).
9. Hamerschlag & Kraus-Polk 2017 [44] USA	School lunch menu designed to be more sustainable	Primary, middle and high schools in the USA.	Climate-conscious menus implemented over one school district. The series of initiatives included: Meatless Monday, Lean and Green Wednesday and ‘California Thursdays’.	One season	Pre–post	85 schools (n = 37,000 pupils)	No comparator group	(1) Reduction in meat/dairy (lb per meal/%); (2) Greenhouse gas emissions (kg CO2-eq per meal served); (3) Water footprint (gallons per meal); (4) Cost saving ($/%).	(1) Pre: 0.14 lb; post: 0.10 lb per meal/30% reduction); (2) Pre: 0.70 kg CO2-eq per meal served; post: 0.61 kg CO2-eq per meal served; (3) Pre: 113 gallon; post: 106 gallon per meal served (4) USD 42,000 less spent per meal (1% per meal less).
10. Ribal et al., 2016 [26] Spain	School lunch menu designed to be more sustainable	School lunch menu data from one school catering company in Spain offering a large variety of meal combinations served with bread and water.	Optimisation of a menu that minimised cost and carbon footprint levels and promoted micronutrients.	N/A	Pre–post (Modelling study)	Optimised menu	Standard menu	Carbon footprint (kg CO2 equivalent)	A 23–24% reduction in the carbon footprint, but when balanced with the average budget, the reduction was 15–16%. Optimised menu had lower calcium content (below the set threshold), but the micronutrient energy share was more balanced.
11. Thorsen et al., 2015 [41] Denmark	School lunch menu designed to be more sustainable	Third and fourth grade primary school children from schools in Denmark with a previously packed lunch option only.	Traditional Nordic diet (environmentally friendly and sourced from the Nordic region).	3 months	Cluster randomised controlled unblinded cross over study	Pupils from 9 schools (n = 187)	Traditional Nordic diet vs. packed lunches	(1) Food intake (g); (2) Edible waste (g/%).	(1) Traditional Nordic diet: 230 g vs. packed lunch: 208 g; (2) Traditional Nordic diet: 88 g/29% vs. packed lunch: 43 g/16%.
12. Lombardini et al., 2013 [40] Finland	School lunch menu designed to be more sustainable	Primary and secondary school pupils from schools in Finland implementing a vegetarian day.	Weekly vegetarian day where no meat or fish products are offered (forced restriction) on the school lunch menu for one day each week.	11 months	Pre–post with comparator	33 schools	10 schools	(1) Participation in school lunch (%); (2) Food taken (g); (3) Food waste (g).	(1) Intervention: pre 83%; post 77%. Control: pre 78%; post 89%. No significant difference between groups; (2) Intervention: pre 288 g; post 35 g. Control: pre 333 g; post 316 g. no s.d. between groups; (3) Intervention: 35 g pre; 56 g post (significant pre–post reduction). Control group: pre 30 g; post 32 g. No significant difference between groups.
13. Orme et al., 2010 [38] England	School lunch menu designed to be more sustainable	Primary, secondary and special schools in England engaged in the Food for Life Partnership scheme.	Food for Life Partnership scheme (FFLP) including the following menu objectives: (1) Use of seasonal menus and in-season produce; (2) Display information about the origins of all fresh produce used; (3) Have at least 30% of ingredients from organic sources; (4) Have at least 50% of ingredients from local suppliers.	18 months	Pre–post	38 schools	No comparator	Number of schools using local suppliers (%)	Increase of 73% of schools using local suppliers.