The paleo diet was one of the most searched diets of the 2010s, inspiring countless cookbooks and a passionate following. Its core claim is simple: eat like our Paleolithic ancestors, and you'll be healthier because that's what our genes are adapted to.
The evolutionary premise is largely wrong. But ironically, the diet itself isn't bad - it just works for different reasons than its advocates claim.
What Is the Paleo Diet?
The paleo diet aims to replicate what proponents believe hunter-gatherers ate before agriculture (roughly 10,000 years ago). The theory is that our bodies haven't adapted to modern foods, causing "diseases of civilisation."
Encouraged Foods
- Meat (especially grass-fed)
- Fish and seafood
- Eggs
- Vegetables
- Fruits
- Nuts and seeds
- Healthy oils (olive, coconut, avocado)
Eliminated Foods
- Grains (wheat, oats, rice)
- Legumes (beans, lentils, peanuts)
- Dairy products
- Refined sugar
- Processed foods
- Vegetable oils (canola, soybean)
- Artificial sweeteners
The Evolutionary Argument (And Why It's Flawed)
The paleo diet rests on an appealing story: our genes are essentially the same as our ancestors', so we should eat the same way. The problem? This story doesn't hold up to scientific scrutiny.
Myth: We Haven't Evolved Since the Paleolithic
Humans have continued evolving. The most famous example is lactase persistence - the ability to digest dairy as adults - which evolved independently in multiple populations after the advent of dairying. Amylase genes (for starch digestion) have also increased in copy number in agricultural populations. Evolution didn't stop.
Myth: There Was One "Paleo Diet"
Paleolithic humans ate whatever was available locally. Inuit ate mostly animal products. Tropical populations ate more plants and tubers. Mediterranean populations ate differently from African ones. There was no single ancestral diet - there were hundreds.
Myth: Modern Foods Are Fundamentally Different
Almost every food we eat has been modified through selective breeding. Modern fruits are sweeter, modern vegetables are larger, modern animals are fatter. The wild ancestors of today's produce would be unrecognisable - and often less nutritious.
The Paradox
The evolutionary reasoning is largely wrong, but the dietary recommendations accidentally align with solid nutritional science: eat whole foods, plenty of protein and vegetables, minimal processing. The diet works - just not for the reasons claimed.
What Does Research Show?
Short-Term Studies: Positive Results
Several controlled trials (typically 2-12 weeks) show paleo diets produce greater weight loss, improved glucose tolerance, and better lipid profiles compared to typical Western diets. However, comparison diets are often poorly controlled, and the effect may largely come from calorie reduction and processed food elimination.
Comparison to Other Healthy Diets: Mixed
When compared to other whole-foods-based diets (Mediterranean, DASH), results are less impressive. A 2019 meta-analysis found paleo produced slightly greater weight loss than control diets but similar results to other healthy eating patterns.
Long-Term Adherence: Unknown
Most paleo studies are short-term. We don't have good data on whether people can maintain this way of eating for years or decades. Anecdotally, many people find the restrictions (especially no grains or legumes) challenging long-term.
What Paleo Gets Right
- Emphasis on whole foods - Minimising processed foods is genuinely beneficial
- High protein intake - Supports satiety, muscle maintenance, and metabolic health
- Plenty of vegetables - Most people don't eat enough
- Reduction in refined sugar - Undeniably positive
- Eliminates ultra-processed foods - Major health benefit
What Paleo Gets Wrong
- Blanket elimination of legumes - Beans and lentils are nutritious, affordable, and well-researched. The "antinutrient" concerns are overstated when legumes are properly prepared.
- No dairy - For those who tolerate it, dairy provides calcium, protein, and other nutrients. Lactose intolerance is common but not universal.
- Dismissal of whole grains - While refined grains are worth limiting, whole grains are associated with reduced cardiovascular disease and mortality in large observational studies.
- The evolutionary justification - Appealing but scientifically unsupported. We don't need to invoke ancestors to explain why whole foods are good for us.
Benefits and Drawbacks
Potential Benefits
- Eliminates ultra-processed foods
- High in protein and vegetables
- May improve blood sugar control
- Simple rules - no calorie counting
- Encourages cooking from scratch
Potential Drawbacks
- Eliminates healthy food groups
- More expensive than mixed diets
- Socially challenging
- May be hard to maintain long-term
- Risk of inadequate fibre/calcium
A Better Approach: "Paleo-ish"
Instead of strict paleo, consider keeping the good principles while dropping the arbitrary restrictions:
- Base meals on protein, vegetables, and whole foods
- Minimise ultra-processed foods and refined sugar
- Include legumes if you tolerate them well
- Include dairy if you tolerate it
- Choose whole grains over refined when eating grains
- Don't stress about whether a food is "paleo" - focus on quality
This gives you 90% of the benefits with none of the unnecessary restriction or evolutionary pseudoscience.
The Bottom Line
The paleo diet works for many people, but not because of evolutionary adaptation. It works because it emphasises protein, vegetables, and whole foods while eliminating processed junk. You can get these same benefits without eliminating entire food groups with genuine nutritional value. The principles are sound; the premise is flawed.
References
- Sohouli, M.H., et al. (2022). The effect of paleolithic diet on glucose metabolism and lipid profile among patients with metabolic disorders: a systematic review and meta-analysis of randomized controlled trials. Critical Reviews in Food Science and Nutrition, 62(17), 4551-4562. doi:10.1080/10408398.2021.1875125
- Ghaedi, E., et al. (2020). Effects of a Paleolithic Diet on Cardiovascular Disease Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Advances in Nutrition, 11(1), 1-13. doi:10.1093/advances/nmz007
- de Menezes, E.V.A., et al. (2019). Influence of Paleolithic diet on anthropometric markers: A systematic review and meta-analysis. Nutrition Journal, 18, 41. doi:10.1186/s12937-019-0457-z
- Whalen, K.A., et al. (2017). Paleolithic and Mediterranean Diet Pattern Scores Are Inversely Associated with All-Cause and Cause-Specific Mortality in Adults. Journal of Nutrition, 147(4), 612-620. doi:10.3945/jn.116.241919
- Zuk, M. (2013). Paleofantasy: What Evolution Really Tells Us about Sex, Diet, and How We Live. W.W. Norton & Company. [Critical analysis of evolutionary diet claims]
