Researchers Map 25 Diverse Indices Designed to Score Diets for Both Human Health and Planetary Impact

A new systematic review in PLOS ONE maps 25 indices used to score meals for health and environment, highlighting the need for a global standardized food label.

By: AXL Media

Published: Apr 3, 2026, 11:05 AM EDT

Source: Information for this report was sourced from News-Medical

The Rise of Combined Nutritional and Environmental Labeling

As global awareness of the food system's role in climate change and biodiversity loss grows, researchers are racing to develop labels that inform consumers about more than just calorie counts. Traditional nutrition labeling is already a regulated staple in regions like the United Kingdom, but there is an increasing demand for "dual-purpose" indices. These tools aim to reduce consumer confusion by providing a single or dual score that reflects how a specific meal or diet impacts both the individual's health and the planet's resources.

Mapping the Growing Toolbox of Sustainability Metrics

The systematic review, which covered original studies published between 2009 and 2025, identified 25 distinct indices designed to classify or rank diets. These Nutritive and Environmental Combined Indices (NECIs) vary significantly in their scope; some were designed specifically for full daily diets, while others focused on individual restaurant or home-cooked meals. Of the tools studied, 17 were developed for European populations, with most targeting adult consumers. This reflects a regional lead in the policy development of sustainable dietary guidelines.

Methodological Heterogeneity and the Standardization Gap

The most significant finding of the study is the "considerable heterogeneity" across the different scoring methods. For example, nutritional scoring often relies on the Nutrient Rich Diet score, but the metrics can be based on either food mass or energy density. Similarly, environmental scoring almost exclusively utilizes Life Cycle Assessment (LCA) data, but researchers found substantial differences in "system boundaries"—the specific stages of food production, from farm to fork, that are actually counted in the final score.