While some suggest that eating meat made early humans’ brains bigger, the tooth scratches don’t prove that—they only show the food was gritty or tough, not that it was high in calories or protein.
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
A systematic review could determine whether increases in hominin brain size across species consistently correlate with isotopic evidence of increased meat consumption, not just dietary abrasiveness.
A systematic review and meta-analysis of all published hominin brain endocast volumes, stable isotope data (δ¹⁵N, δ¹³C), and microwear metrics from 2.0–0.1 million years ago, testing whether brain size expansion correlates more strongly with carnivory indicators than with microwear abrasion.
A long-term study of modern primates or humans consuming high-meat vs. high-grit diets could test whether brain size changes are linked to meat, not abrasion.
A 10-year cohort study of 50 captive primates (e.g., chimpanzees) assigned to either a high-meat, low-grit diet or a low-meat, high-grit diet, measuring brain volume via MRI annually to test whether meat intake, not abrasion, drives neural growth.
A case-control study comparing isotopic evidence of meat consumption in hominins with large vs. small brains could test whether brain size correlates with carnivory, not abrasion.
A case-control study comparing δ¹⁵N isotopic values in 30 hominin fossils with brain volumes >900 cc (cases) versus 30 with brain volumes <800 cc (controls), matched for age, site, and microwear abrasion, to test for higher carnivory in larger-brained individuals.
A cross-sectional study of modern humans with varying meat intake could test whether brain size (via MRI) correlates with dietary protein, not food abrasiveness.
A cross-sectional study of 200 modern adults with documented meat intake (via dietary logs) and brain volume measured by MRI, controlling for total calories, fat, and carbohydrate intake, to test whether meat consumption correlates with brain size.
A case series documenting brain development in individuals consuming high-meat diets could provide anecdotal support, though not causal evidence.
A case series of 5 children raised on high-meat, low-carbohydrate diets from birth, with annual brain MRI scans and dietary logs to document brain growth trajectories.