A new protein-ranking framework from the University of Cambridge is challenging the way consumers compare foods, placing tofu at the top of a 20-food evaluation and cheddar cheese at the bottom. Published in Frontiers in Sustainable Food Systems, the analysis argues that no single measure—whether carbon emissions, nutritional quality, price or supermarket availability—can adequately describe the overall value of a protein source. Instead, it introduces the Better Protein Institute Score, or BPI Score, a multidimensional system designed to examine how food choices affect both human well-being and the planet.
The framework was developed by Dr Chris Macdonald, a fellow at Lucy Cavendish College, University of Cambridge, and director of the Better Protein Institute. Its central premise is that consumers are often asked to make complex decisions using incomplete information. A product may be inexpensive but environmentally damaging, highly nutritious but difficult to obtain, or relatively sustainable but high in sodium or saturated fat. The BPI Score attempts to bring these competing factors into a single analytical structure, allowing foods to be compared across several dimensions at once.
When the system was applied to 20 commonly consumed, protein-rich foods, the results revealed a pronounced divide between plant- and animal-based products. Every food in the highest-scoring fifth of the ranking was plant-based, while every product in the lowest-scoring fifth was animal-based. Tofu achieved the highest overall score, whereas cheddar cheese ranked last. The findings do not mean that one food is universally suitable for every diet or that all plant-based products are automatically healthier, but they demonstrate how dramatically rankings can change when environmental and social considerations are evaluated alongside nutrition.
The environmental component of the score compares foods according to their impact per 100 grams of protein rather than per 100 grams of product. This standardisation is technically important because protein concentrations vary widely: a food that appears efficient by weight may provide relatively little protein, while a more concentrated source may require a smaller serving. The environmental assessment incorporates greenhouse-gas emissions, land use, freshwater consumption and water pollution. By expressing the results on an equivalent-protein basis, the framework seeks to make comparisons between foods such as beef, tofu, dairy products and legumes more meaningful.
According to the analysis, the differences between some protein sources are substantial. Beef, for example, produces considerably more greenhouse-gas emissions and uses far more land than tofu when the foods are compared according to the amount of protein they provide. These differences reflect the biological and agricultural systems behind each product. Cattle require feed, land and water throughout their lives and also emit methane, a potent greenhouse gas. Soybeans used to make tofu generally convert agricultural inputs into edible protein more efficiently, although the environmental performance of any food can vary depending on farming practices, transport, processing and location.
The second major component, described as the “people” category, combines health, affordability and availability. Nutritional scoring considers factors including sodium, saturated fat and cholesterol, as well as whether a food supplies all nine essential amino acids that humans must obtain through their diet. Protein sources containing all essential amino acids in adequate proportions are often described as complete proteins. However, the framework also recognises that overall dietary quality depends on the combination of foods consumed, not simply on the biological profile of an individual ingredient.
Affordability and availability add a practical dimension that is often absent from environmental or nutrition labels. A protein source may perform well in laboratory comparisons but be inaccessible to people because of its price, limited distribution or cultural unfamiliarity. By including supermarket availability and cost, the BPI Score attempts to reflect the real-world constraints that shape dietary choices. This makes the system less like a simple sustainability league table and more like a decision-making tool intended for consumers, institutions and policymakers.
Macdonald presents the score not as a replacement for existing labels but as a way to improve food literacy. Many current rating systems focus on one issue, such as carbon emissions, traffic-light nutrition values or animal-welfare standards. These labels can be useful, but they may also encourage consumers to treat a single metric as a complete verdict. A multidimensional score can reveal trade-offs, although it cannot eliminate the value judgments involved in deciding how much importance should be assigned to health, environmental damage, price or availability.
Because the BPI Score is based on a framework rather than a controlled dietary intervention, it does not demonstrate that eating tofu will directly improve a person’s health or that consuming cheddar will necessarily cause harm. The rankings depend on the quality of the underlying data, the boundaries selected for environmental assessment and the relative weighting of different criteria. Farming systems, brands, preparation methods and regional food markets can also produce different results. Nevertheless, the study offers a highly shareable conclusion: when protein foods are judged simultaneously by their effects on people, ecosystems and household budgets, plant-based options dominate the top of the ranking while several animal-based foods occupy the bottom.
The paper’s broader message is that protein choices are not merely nutritional decisions. They connect personal health with land use, climate emissions, water quality, food access and the future resilience of food systems. By combining these issues into one framework, the BPI Score aims to help the public see consequences that conventional packaging often leaves out. The author argues that the goal is not to create another marketing label, but to encourage a more informed understanding of the systems behind everyday meals.
Subject of Research: Food and protein sources
Article Title: “What are the best sources of protein? Introducing the BPI Score”
News Publication Date: 29-Jul-2026
Web References: https://doi.org/10.3389/fsufs.2026.1677796
References: Macdonald, C. “What are the best sources of protein? Introducing the BPI Score.” Frontiers in Sustainable Food Systems. DOI: 10.3389/fsufs.2026.1677796
Keywords: protein sources, tofu, cheddar cheese, plant-based food, sustainable food systems, environmental impact, nutrition, greenhouse-gas emissions, food affordability, BPI Score
