Reducing energy intake and energy density for a sustainable diet: a study based on self-selected diets in French adults.
BACKGROUND
Studies on theoretical diets are not sufficient to implement sustainable diets in practice because of unknown cultural acceptability. In contrast, self-selected diets can be considered culturally acceptable.


OBJECTIVE
The objective was to identify the most sustainable diets consumed by people in everyday life.


METHODS
The diet-related greenhouse gas emissions (GHGE) for self-selected diets of 1918 adults participating in the cross-sectional French national dietary survey Individual and National Survey on Food Consumption (INCA2) were estimated. "Lower-Carbon," "Higher-Quality," and "More Sustainable" diets were defined as having GHGE lower than the overall median value, a probability of adequate nutrition intake (PANDiet) score (a measure of the overall nutritional adequacy of a diet) higher than the overall median value, and a combination of both criteria, respectively. Diet cost, as a proxy for affordability, and energy density were also assessed.


RESULTS
More Sustainable diets were consumed by 23% of men and 20% of women, and their GHGE values were 19% and 17% lower than the population average (mean) value, respectively. In comparison with the average value, Lower-Carbon diets achieved a 20% GHGE reduction and lower cost, but they were not sustainable because they had a lower PANDiet score. Higher-Quality diets were not sustainable because of their above-average GHGE and cost. More Sustainable diets had an above-average PANDiet score and a below-average energy density, cost, GHGE, and energy content; the energy share of plant-based products was increased by 20% and 15% compared with the average for men and women, respectively.


CONCLUSIONS
A strength of this study was that most of the dimensions for "sustainable diets" were considered, ie, not only nutritional quality and GHGE but also affordability and cultural acceptability. A reduction in diet-related GHGE by 20% while maintaining high nutritional quality seems realistic. This goal could be achieved at no extra cost by reducing energy intake and energy density and increasing the share of plant-based products.
From the Unité Mixte de Recherche "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique, Institut National de la Santé et de la Recherche Médicale, Aix- Marseille Université, Marseille, France (GM, FV, and ND); AgroParisTech, Nutrition Physiology and Ingestive Behavior, Paris, France and Danone Research, Global Nutrition Department, Palaiseau, France (EOV); and UR "Aliss," Ivry sur Seine, France (L-GS and DT).
Gabriel
G
Masset
From the Unité Mixte de Recherche "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique, Institut National de la Santé et de la Recherche Médicale, Aix- Marseille Université, Marseille, France (GM, FV, and ND); AgroParisTech, Nutrition Physiology and Ingestive Behavior, Paris, France and Danone Research, Global Nutrition Department, Palaiseau, France (EOV); and UR "Aliss," Ivry sur Seine, France (L-GS and DT).
Florent
F
Vieux
From the Unité Mixte de Recherche "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique, Institut National de la Santé et de la Recherche Médicale, Aix- Marseille Université, Marseille, France (GM, FV, and ND); AgroParisTech, Nutrition Physiology and Ingestive Behavior, Paris, France and Danone Research, Global Nutrition Department, Palaiseau, France (EOV); and UR "Aliss," Ivry sur Seine, France (L-GS and DT).
Eric Olivier
EO
Verger
From the Unité Mixte de Recherche "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique, Institut National de la Santé et de la Recherche Médicale, Aix- Marseille Université, Marseille, France (GM, FV, and ND); AgroParisTech, Nutrition Physiology and Ingestive Behavior, Paris, France and Danone Research, Global Nutrition Department, Palaiseau, France (EOV); and UR "Aliss," Ivry sur Seine, France (L-GS and DT).
Louis-Georges
LG
Soler
From the Unité Mixte de Recherche "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique, Institut National de la Santé et de la Recherche Médicale, Aix- Marseille Université, Marseille, France (GM, FV, and ND); AgroParisTech, Nutrition Physiology and Ingestive Behavior, Paris, France and Danone Research, Global Nutrition Department, Palaiseau, France (EOV); and UR "Aliss," Ivry sur Seine, France (L-GS and DT).
Djilali
D
Touazi
From the Unité Mixte de Recherche "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique, Institut National de la Santé et de la Recherche Médicale, Aix- Marseille Université, Marseille, France (GM, FV, and ND); AgroParisTech, Nutrition Physiology and Ingestive Behavior, Paris, France and Danone Research, Global Nutrition Department, Palaiseau, France (EOV); and UR "Aliss," Ivry sur Seine, France (L-GS and DT).
Nicole
N
Darmon
D000328:Adult; D000368:Aged; D031204:Caloric Restriction / Q000009:adverse effects / Q000191:economics; D003247:Conservation of Natural Resources / Q000191:economics; D003365:Costs and Cost Analysis; D003430:Cross-Sectional Studies; D002149:Energy Intake; D005260:Female; D063427:Food Quality; D005523:Food Supply / Q000191:economics; D005602:France; D017752:Greenhouse Effect / Q000517:prevention & control; D006293:Health Promotion; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D018673:Nutrition Policy; D009749:Nutrition Surveys; D009753:Nutritive Value; D010349:Patient Compliance; D055815:Young Adult