image: Two bar charts comparing greenhouse gas emissions and water pollution produced by plant-based and animal-based protein sources per 100 g of protein.
Credit: Chris Macdonald
What are the best sources of protein?
Published in Frontiers in Sustainable Food Systems, Dr Chris Macdonald explored what are the best sources of protein currently available.
To answer the question, Dr Macdonald had to build a new holistic scoring system that combines measures of environmental impact, health, affordability, and availability into a single framework.
Applying the scoring system to 20 commonly consumed protein-rich foods, the analysis found a striking pattern: every product in the highest-scoring quintile was plant-based, while every product in the lowest-scoring quintile was animal-based. Tofu ranked first overall, while cheddar cheese ranked last.
The paper argues that many existing food rating systems focus on only one aspect of a product. While useful, these single-dimension labels can obscure important trade-offs and make it difficult to compare foods comprehensively.
As noted in the paper, “Against deliberate corporate obfuscation and marketing myths, the goal of a holistic score is not to create a new label, but to foster a new literacy, one that empowers us to see the reality of the systems we are funding.
Ultimately, beyond the spreadsheets and scores, lies a fundamental reckoning: our protein choice is a referendum on the compassion we are willing to show to animals, to the planet, and to future generations.”
The new publication builds upon Dr Macdonald’s work at the Better Protein Institute, which also explores how much protein we need for optimal health outcomes, how to effectively shift consumer behaviour, and the best investment opportunities for future sources of protein.
By challenging assumptions and starting from first principles, Dr Macdonald is answering some of the most Googled questions relating to dietary protein.
Journal
Frontiers in Sustainable Food Systems
Method of Research
Data/statistical analysis
Subject of Research
People
Article Title
What are the best sources of protein? Introducing the BPI Score
Article Publication Date
29-Jul-2026
COI Statement
The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.