Food-based indices for the assessment of nutritive value and environmental impact of meals and diets: A systematic review

Nutrient scoring systems assign higher health scores to plant-based foods than to animal-based foods.

Nutritive and Environmental Combined Indices are mostly created by universities using existing data from nutrient databases and environmental studies, but because they do not use consistent input data, their results cannot be reliably reproduced.

Twenty-five different food indices exist that evaluate meals and diets based on nutrition and environmental impact, but they use 27 different methods, resulting in inconsistent scoring, weighting, and presentation that prevent direct comparison.

Most food environmental impact assessments use Life Cycle Assessment, primarily measuring greenhouse gas emissions, and often ignore other environmental factors, which limits their overall scope.

Nineteen out of 25 food sustainability indices merge health and environmental scores into one number, while six keep them separate; merging them obscures how improvements in one area may come at the cost of the other.

Only 21 out of 25 methods used to assess food intake in research can be reliably repeated by other scientists because the details are not clearly described, revealing a widespread lack of standardization in how food data is measured.