Table 1.

Overview of the 12 diet studies with both nutritional and ecological constraints.

Study	Goal	Outcome	Comment
(13)	To assess the impact of diet change on the blue and green water footprints of food consumption	Green water: −6, −11, −15, −21%. Blue water: −4, −6, −9, −14%. Halving animal protein saves water for the diet of an additional 1.8 billion people	Recommended diet per country not specified
(16)	Estimate likely changes in diet under healthy eating guidelines and their consequences for the agricultural sector	Increase of 131.4% in gross margins; increase land use of oats, potatoes, fruits, and vegs; decrease use of sugar beet, milk, beef, sheep, beans, and some cereals
(17)	Whether a reduction in GHGEs can be achieved while meeting dietary requirements	2.43 kg CO2eq/d (−36%) and GBP 29.-/wk	No drinks included
(18) (Spain)	To determine whether it is possible to develop corresponding diet recommendations in other countries; to analyse the difficulties of integrating data from multiple sources	25% reduction in GHGe: 2,710g CO2e/day. Costs € 3.48 (unchanged)	Ignored the effect of alcohol and drinks
(18) (Sweden)		25% reduction in GHGe: 4,295g CO2e/day. Costs SEK 44.07 (−0.57)	All diets show reduction in total amount of meat and increase in legumes and bread/ pasta/ potatoes
(18) (France)		25% reduction in GHGe: 2,609g CO2e/day. Costs € 4.36 (−0.54)
(19)	Ensuring food security in the context of rising food prices and environmental constraints	5.98 kg CO2eq/d and NZ$ 6.75	No drinks included
(20)	To find low climate impact diets that are affordable yet fulfill all nutritional requirements	1.58 kg CO2eq/day and € 2.57
(21)	Demonstrate a method that is able to identify diets with reduced environmental impact and that are more similar to the current diet than predetermined scenarios	30% less environmental impact (0.29 pt pReCiPe)	Diet compared with (pesco)vegetarian, vegan, closest healthy
(22)	To model the specific reductions in food-related GHGEs that could be achieved while meeting international dietary recommendations and minimizing deviation from the current diet	WHO guidelines −17% GHGE, realistic modifications −40% GHGE (fewer animal products and processed snacks, more fruit, vegetables, and cereals)	More than 40% is unlikely without radical change
(23)	To assess the compatibility between reduction of diet-related GHGEs and nutritional adequacy, acceptability and affordability dimensions	GHGE reductions up to 30%; higher GHGE reductions decreased diet cost but also diet quality with major shifts in diet	3 levels of nutritional constraints; stepwise 10% GHGE reduction; aggregation into food groups with new Euclidean distance method
(24)	To investigate the diversity in dietary changes needed to achieve a healthy diet and a healthy diet with lower GHGEs by taking into account each individual's current diet and then minimizing the changes they need to make	Only 7.5% of people achieved healthy diet and 4.6% sustainable diet; 15 and 27% reduction in GHGEs, respectively; healthy diets alone do not produce substantial reductions in GHGEs	4 step model; using 7–10 new items, 95% met health or GHGE constraints; sodium most difficult nutrient to meet; healthy diets alone do not produce substantial reductions in GHGE
(25)	To identify a healthy, greener and cheaper diet based on current consumption patterns	More than 50% CO2 reduction for 3 diets to 8.3 kg CO2/wk; 10 euro/wk cost reduction (25%) for the low cost diet
(26)	To demonstrate that linear programming can be used to define nutritionally healthy, environmentally friendly, and culturally acceptable diets, using the Low Lands as an example	Optimized Low Lands Diet results in a lower environmental impact than the Mediterranean and New Nordic Diet; GHGEs are 2.60 kg CO2eq/day and LU 2.86 m2*year/day	Retrospective study about optimizing the traditional Low Lands Diet

The table gives details about the goal, outcomes and comments.