Sustainable nutrition
Nutritional Life Cycle Assessment: connecting environmental impact and health
When discussing sustainability in food systems, understanding environmental impact is only part of the picture. Food serves a specific function: to nourish. Improving environmental performance should therefore not come at the expense of nutritional adequacy or health. Life Cycle Assessment helps to quantify environmental impact. But on its own, it does not capture what food contributes to the human diet. Nutritional Life Cycle Assessment (nutritional LCA) is an emerging approach that aims to bridge this gap. It combines environmental impact with nutritional value, creating a more complete basis for evaluating food products and diets.
Moving beyond mass-based comparisons
Traditional LCA expresses environmental impact per unit of product, typically per kilogram. While this works well for many applications, it introduces a limitation for food. Products differ significantly in their nutritional function, and comparing them purely on a mass basis may lead to misleading conclusions. Nutritional LCA addresses this by linking environmental impact to nutritional value. Instead of asking what is the impact per kilogram, it asks: what is the impact per unit of nutrition provided?
This shift, from mass to function, aligns environmental assessment more closely with the role of food in the diet.
Different approaches to nutritional LCA
There is currently no single agreed methodology for nutritional LCA. Several approaches exist, each reflecting different ways of defining nutritional value.
One approach is based on serving sizes, expressing environmental impact per portion. This aligns with how food is consumed and can be intuitive for communication. At the same time, serving sizes are not standardized and may vary between contexts.
Another approach focuses on individual nutrients, such as protein or energy. Environmental impact is expressed per unit of a specific nutrient. This can be useful for comparing products with a similar function, but it reduces nutrition to a single dimension and may overlook broader dietary quality.
A more comprehensive approach uses nutrient density indices, such as Nutrient Rich Food (NRF) scores. These combine multiple nutrients, typically distinguishing between nutrients to encourage and nutrients to limit. While more holistic, these methods require choices on which nutrients to include and how to weight them.
Finally, nutritional LCA can be applied at the level of the overall diet, using optimization approaches. These models identify dietary patterns that meet nutritional requirements while minimizing environmental impact. This shifts the focus from individual products to system-level outcomes, but depends strongly on assumptions about dietary constraints and preferences.
Each approach offers different insights, leading to different conclusions. This diversity reflects the complexity of linking nutrition and environmental impact.
Why nutritional LCA matters
Integrating nutrition into environmental assessment helps address an important risk: unintended trade-offs. A product with a lower environmental impact per kilogram may contribute little to nutritional needs. Conversely, nutritionally valuable foods may appear less favourable when assessed purely on environmental terms. Studies show that conclusions about the sustainability of foods can change significantly depending on whether nutritional value is included, and how it is defined. This highlights that environmental and nutritional dimensions cannot be considered in isolation. Nutritional LCA provides a framework to explore these interactions. It can support more balanced decision-making in research, policy, and business, helping to align environmental sustainability with healthy diets.
Challenges in practice
Despite its potential, nutritional LCA is still developing, and several challenges remain.
A central challenge is the lack of methodological consensus. Different approaches—serving sizes, single nutrients, nutrient indices, or dietary optimization can lead to different outcomes. This makes comparison difficult and limits broader application.
Closely related is the issue of defining nutritional value. Nutritional quality is multi-dimensional, and there is no single metric that fully captures it. Choices about which nutrients to include, how to weight them, and how to treat nutrients to limit introduce subjectivity.
Another challenge is functional comparability. Foods do not serve identical roles in the diet, and comparing them, even when adjusted for nutrition, remains complex.
There are also data and integration challenges. While nutritional composition data are widely available, linking them consistently with environmental data, especially at product-specific level, requires careful alignment.
Finally, nutritional LCA operates at the interface of disciplines. Aligning insights from environmental science, nutrition science, and health research remains an ongoing challenge.
Where nutritional LCA can be used
Nutritional LCA can be applied across different levels. At the product level, it can support comparisons between alternatives that provide a similar nutritional function. At the portfolio level, it can guide product development towards options that perform well both environmentally and nutritionally. At the system level, it can inform dietary guidelines and explore pathways towards more sustainable diets. It can also play a role in ecolabelling, although translating combined environmental and nutritional information into clear and meaningful communication remains a challenge.
Looking ahead
There is significant potential to further develop nutritional LCA. One important area is the inclusion of bioavailability, recognizing that the nutritional value of food depends not only on composition, but also on how nutrients are absorbed and utilized. Another area is the integration of health outcomes, linking dietary patterns not only to nutrient intake, but also to impacts on health and disease. This would move beyond nutrient-based metrics towards a more outcome-oriented perspective.
These developments would further strengthen the connection between environmental sustainability and human health.
From development to application
Nutritional LCA builds on Life Cycle Assessment, extending it into the domain of nutrition. By linking environmental impact to nutritional value, it makes explicit a connection that is often treated separately. Sustainability in food systems is not only about reducing environmental impact; it is also about supporting healthy diets. Nutritional LCA is still evolving. Methodological questions remain, and further development is needed to improve consistency, robustness, and scope. At the same time, these challenges should not prevent its application.
Even in its current form, nutritional LCA provides valuable insights, highlighting trade-offs, revealing unintended consequences, and supporting more informed decision-making. Waiting for full consensus or methodological perfection risks delaying progress in areas where better decisions are already possible. This does not mean that nutritional LCA should be applied for all use-cases the same way. Some applications—such as on-pack communication in retail—might require a level of robustness, comparability, and simplicity that is not yet fully achieved. Consumer research on how such information affects purchasing behavior could also be useful here.
But in other contexts—such as research, product development, or strategic decision-making, nutritional LCA can already play a meaningful role. Developing the method and applying it in practice are not sequential steps, but parallel processes. Using nutritional LCA where it adds value, while continuing to refine and improve it, allows both the methodology and its impact to evolve together.