Our bodies are built to use animal fats because that’s what our ancestors ate for thousands of years.
Scientific Claim
Human physiology is evolutionarily adapted to metabolize and utilize animal-derived saturated and monounsaturated fats as primary dietary lipids.
Original Statement
“The main type of fat humans consumed was animal fats. This is what makes them so great. They are the only fat that humans are biologically adapted to.”
Context Details
Domain
evolutionary-nutrition
Population
human
Subject
human physiology
Action
is evolutionarily adapted to
Target
metabolize and utilize animal-derived saturated and monounsaturated fats as primary dietary lipids
Intervention Details
Evidence from Studies
Supporting (2)
When people swapped animal fats for plant fats, their blood fats got better but their blood vessels stayed the same — suggesting our bodies are fine with animal fats, and just get a little extra benefit when we swap them out.
Technical explanation
This study compares replacing saturated fats with unsaturated fats and finds that while vascular function didn’t change, lipid biomarkers improved — implying saturated fats are a baseline dietary lipid that human physiology is adapted to, and replacing them yields metabolic benefits without harming vascular function.
This study found that eating saturated fat from butter helps the body remove bad cholesterol from arteries, suggesting our bodies are built to handle animal fats well.
Technical explanation
This paper directly tests the metabolic impact of animal-derived saturated fats (from butter) on HDL-mediated cholesterol efflux, a key process in lipid utilization and cardiovascular health, supporting the idea that animal-derived SFAs are metabolically active and can have beneficial effects in human physiology.
Contradicting (2)
Eating a lot of animal products can make bad stuff in the gut that harms health — which means our bodies might not be perfectly built for eating lots of animal fats like our ancestors did.
Technical explanation
While focused on protein, this paper highlights that high animal-based diets produce toxic metabolites via gut microbiota, suggesting that modern human physiology may not be fully adapted to high animal fat/protein diets, indirectly contradicting the assertion.
People who ate a lot of saturated fats (like butter and fatty meat) were much more likely to get heart disease — suggesting our bodies aren’t perfectly adapted to handle large amounts of these fats.
Technical explanation
This study directly links a dietary pattern high in saturated fatty acids with increased risk of coronary heart disease in humans, contradicting the assertion that human physiology is evolutionarily adapted to use animal-derived saturated fats as primary lipids without harm.