Paleo Diet
Lean meats, fish, fruits, and vegetables — modeled on pre-agricultural eating.
How It Works
Paleo is modeled on a presumed hunter-gatherer eating pattern: lean meats, fish, fruits, vegetables,
nuts, and seeds, while excluding grains, legumes, dairy, refined sugar, and processed foods. The
rationale is that human genetics and physiology haven't had much time to adapt to farming-era foods
(grains, legumes, dairy), which are evolutionarily recent relative to hunter-gatherer eating.
Worth knowing: this "one ancestral diet" premise has been directly challenged in the scientific
literature. Lieberman DE, et al., "Comparing measured dietary variation within and between tropical
hunter-gatherer groups to the Paleo Diet," American Journal of Clinical Nutrition, 2023,
analyzed 11 tropical forager groups and found their macronutrient ratios varied far more widely than
the range Paleo assumes — concluding the ethnographic record doesn't support the idea of one
circumscribed ancestral macronutrient pattern. In plain terms: there wasn't a single "paleo diet" that
actual hunter-gatherers ate.
Read the critique →
The Research
The evidence base here is real but noticeably thinner and shorter-term than Mediterranean or DASH — a handful of small trials running weeks to months, not decades of cohort data.
Trial: Lindeberg S, Jönsson T, Granfeldt Y, et al. "A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease," Diabetologia, 2007. A 12-week RCT of 29 people with ischemic heart disease and impaired glucose tolerance found the paleo group's glucose tolerance improved substantially more than the Mediterranean-like diet group's, independent of the change in waist circumference.Read the trial →
Additional research:
Ghaedi E, Mohammadi M, Mohammadi H, et al. "Effects of a Paleolithic Diet on Cardiovascular Disease Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials," Advances in Nutrition, 2019. Pooling 8 RCTs, paleo diets modestly improved weight, waist circumference, blood pressure, and lipid markers versus comparison diets — but the authors themselves caution the results were sensitive to which studies were included, and call the evidence "not conclusive." A published comment on this same meta-analysis flagged calculation errors in it, so treat its exact effect sizes with caution even while the general direction (modest short-term improvement) is plausible.
Read the meta-analysis →
Food Examples
Emphasized: grass-fed beef, chicken, wild-caught salmon, eggs, almonds, walnuts,
pumpkin seeds, berries, apples, leafy greens, broccoli, sweet potatoes, olive oil, avocado.
Excluded: wheat bread and pasta, rice, oats, beans and lentils, peanuts (technically a
legume), milk, cheese and yogurt, table sugar, chips, and packaged snacks.
A Sample Day
Breakfast: scrambled eggs with spinach and avocado.
Lunch: grilled chicken salad with mixed greens, olive oil, walnuts, and berries.
Dinner: baked salmon, roasted sweet potato, steamed broccoli.
Snack: apple slices with almond butter.
Who It Might Suit
May suit people who tend to feel and perform better cutting out processed foods, added sugar, and refined carbs generally — regardless of whether the "ancestral" framing itself holds up. It may not suit people who rely on grains, legumes, or dairy as affordable staple protein, fiber, or calcium sources, since paleo-compliant meat, fish, nuts, and produce typically cost more; vegetarians and vegans, since the diet removes legumes and dairy, two of their main protein sources, without offering an alternative; or anyone with higher carbohydrate needs, including some athletes and certain medical contexts.