Cooking nuts and other fatty foods may have helped early humans grow bigger brains and be more active because it gave them more energy from the same food — like getting a free energy boost.
Scientific Claim
Thermal processing of lipid-rich foods may have contributed to human evolutionary adaptations by increasing net energy availability, supporting the expansion of energetically expensive traits such as brain size and locomotor activity.
Original Statement
“Our findings therefore imply that cooking these foods would have raised the human energy budget, helping fuel expensive increases in body mass, brain size, locomotor activity and other costly physiological traits.”
Evidence Quality Assessment
Claim Status
overstated
Study Design Support
Design cannot support claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The study was conducted in mice and cannot directly support claims about human evolution. The evolutionary claim is speculative and extrapolated beyond the data.
More Accurate Statement
“In mice, cooking lipid-rich foods is associated with increased net energy gain, which is consistent with the hypothesis that thermal processing of energy-dense foods may have contributed to human evolutionary adaptations by enhancing dietary energy availability.”
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Prospective Cohort StudyLevel 2bWhether populations with longer histories of cooking lipid-rich foods show correlated increases in brain size or metabolic efficiency.
Whether populations with longer histories of cooking lipid-rich foods show correlated increases in brain size or metabolic efficiency.
What This Would Prove
Whether populations with longer histories of cooking lipid-rich foods show correlated increases in brain size or metabolic efficiency.
Ideal Study Design
A comparative anthropological study of 10+ human populations with varying histories of nut-roasting, measuring cranial capacity, basal metabolic rate, and energy expenditure via doubly labeled water, controlling for diet composition and climate.
Limitation: Cannot establish causation or isolate cooking from other cultural or environmental factors.
Case-Control StudyLevel 3Whether ancient hominin remains show evidence of increased energy allocation to brain growth coinciding with archaeological evidence of controlled fire use.
Whether ancient hominin remains show evidence of increased energy allocation to brain growth coinciding with archaeological evidence of controlled fire use.
What This Would Prove
Whether ancient hominin remains show evidence of increased energy allocation to brain growth coinciding with archaeological evidence of controlled fire use.
Ideal Study Design
A paleoanthropological case-control study comparing 50 hominin fossils with and without evidence of controlled fire use, measuring endocranial volume, body mass estimates, and isotopic signatures of dietary fat intake.
Limitation: Fossil data are sparse and indirect; cannot measure actual energy gain.
Animal Model StudyLevel 2bWhether long-term feeding of cooked lipid-rich diets alters brain size or metabolic traits in primates.
Whether long-term feeding of cooked lipid-rich diets alters brain size or metabolic traits in primates.
What This Would Prove
Whether long-term feeding of cooked lipid-rich diets alters brain size or metabolic traits in primates.
Ideal Study Design
A 10-year longitudinal study in captive chimpanzees (n=30) fed either raw or cooked nuts/seeds, measuring brain volume via MRI, metabolic rate, and activity levels, with controls for total caloric intake.
Limitation: Ethical and logistical constraints limit feasibility and generalizability to humans.
Evidence from Studies
Supporting (1)
Cooking increases net energy gain from a lipid-rich food.
Cooking peanuts made it easier for mice to get more energy from them, because heat broke open the tiny shields around the fats. This suggests that early humans may have gotten more energy from cooked nuts and meats, helping their brains and bodies grow bigger.