Search any grocery store for protein-rich food that’s good for both you and the planet, and you’re buffeted by certified labels claiming organic-grown, ocean-friendly, low-carbon, fair trade, free range, or other shining attributes. These well-meaning labels can obscure serious tradeoffs—for example healthy tree nuts that minimize greenhouse emissions while guzzling scarce water, or organic meats and cheeses that spew water pollution or planet-warming gases. A health tech scientist has proposed a new solution to this problem, in Frontiers in Sustainable Food Systems.
The paper sketches a new rating system for high-protein foods that encompasses multiple dimensions of environmental, health, and human impacts—calculating simple overall scores that can be compared across a variety of plant- and animal-derived foods. “The goal is not necessarily to create another front-of-package label, but to foster a new literacy” that enables better-informed decision-making, writes Chris Macdonald of the University of Cambridge in the United Kingdom.
Maintaining sufficient dietary protein is a major concern when it comes to reconciling modern agriculture with future climate change. Scientists have spent years searching for new, non-meat protein sources, ranging from marigold flowers to fungi to alternative cropping schemes. But currently available non-meat foods are also high in protein, and Macdonald has found that misunderstandings about protein content are a major factor preventing people from choosing these planet-friendly foods over meats and dairy.
In his latest research, Macdonald is trying to provide people with information that is accurate, comprehensive, and simple, so they can make good choices on dietary proteins. He mined scientific data on the environmental impacts and nutrient contents of various foods to develop two simple ratings. A Planet Score, ranging from 0 to 16, includes measures of greenhouse emissions, water pollution, water use, and land use per hundred grams of protein. A separate People Score, ranging from 0 to 24, includes measures of cholesterol, saturated fat, sodium, essential amino acids, commercial availability, and affordability. The Planet and People scores are then combined into an overall Better Proteins Institute (BPI) score.
When Macdonald applied the system to 20 foods (10 animal and 10 plant), tofu, chia seeds, beans, and quinoa had the highest scores (30 to 36), while cheddar, mozzarella, lamb chops, and beef steak had the lowest scores (13 to 16). The highest-scoring animal foods were chicken breast and tuna, ranking 7th and 8th out of 20, based largely on their affordability, low saturated fats, low land use, and moderate greenhouse emissions. Walnuts and brazil nuts were the lowest-scoring plant foods, ranking 11th and 12th out of 20, due to their high prices, saturated fats, and water use.
Macdonald views this as a starting point, which he hopes to improve over time. Affordability and commercial availability, for example, were determined within the U.K. for this study—but they will vary substantially between regions. Future versions may also contain additional factors such as fair trade, ethical treatment of workers, or animal treatment.
Macdonald. “What are the best sources of protein? Introducing the BPI score.” Frontiers in Sustainable Food Systems, 2026.
image: ©Anthropocene Magazine
