Is the Paleo Diet Healthy? What the Science Actually Says

Is the Paleo diet actually healthy? Should you eliminate grains, legumes, and dairy to "eat like your ancestors"? A 2019 study found that long-term Paleo dieters had lower beneficial gut bacteria, reduced microbial diversity, and higher levels of TMAO, a compound linked to cardiovascular disease. The ancestral wisdom might be more modern anxiety than evolutionary truth.

This episode traces the Paleo diet from its actual origins—not CrossFit boxes in 2010, but 1890s "wilderness cults," Gilded Age masculinity panic, and upper-class men doing caveman cosplay to feel less soft. We cover the founders (one was a eugenicist who advocated for the mass slaughter of dolphins), the rules, and why the whole framework is based on foods that didn't exist in the Paleolithic era.

What the research says:

The "mismatch hypothesis"—the idea that our bodies haven't adapted since the Stone Age—doesn't hold up. Evolutionary biologist Marlene Zuk's Paleofantasy dismantles this claim: humans have continued evolving, developing lactase persistence, smaller jaws, and changed gut microbiomes in response to agriculture.

A 2015 systematic review (Mannheimer et al.) on Paleo and metabolic syndrome was followed by a 2016 response (Jacobs et al.) titled "Paleo Diets Still Lack Evidence"—citing small sample sizes, high dropout rates, and confidence intervals that don't support the abstracts' claims.

A 2019 study (Genoni et al.) found Paleo dieters had significantly lower resistant starch intake and worse gut microbiome markers than controls. Eliminating whole grains and legumes removes the prebiotics your gut bacteria need to thrive.

Why Paleo "works" when it works:

When people feel better on Paleo, it's usually because they're eating more vegetables, more protein, fewer ultra-processed foods, and paying attention to what they eat. You can get all of those benefits without eliminating food groups humans have been eating for 10,000 years—and without tanking your gut microbiome.

The bigger picture:

Paleo isn't just a diet. It's an ideological package, one that reveals anxieties about gender, modernity, and control. The diet rebranded restriction, historically coded as feminine, into something rugged and "optimized." You're not meal prepping, you're preparing for societal collapse. According to 2018 Gallup data, liberals are 5.5 times more likely to be vegetarian than conservatives. Meat consumption has become identity, and you can buy your way back to nature for $500 million a year.

The risks:

Beyond gut health concerns, Paleo's restriction and purity language can trigger orthorexia and exacerbate disordered eating—especially when wrapped in performance and masculinity rhetoric. The diet is also expensive (~$12/day) and environmentally unsustainable at scale.

Research on the Paleo diet is limited and often low-quality. A 2019 study found that long-term Paleo dieters had lower beneficial gut bacteria, less microbial diversity, and higher TMAO levels—a marker linked to cardiovascular disease. While some people feel better eating Paleo, the benefits likely come from eating more vegetables, more protein, and fewer processed foods—not from eliminating grains and legumes, which provide important prebiotics for gut health.

References

Books

• Arnold DeVries, Primitive Man and His Food (1952)

• Walter L. Voegtlin, The Stone Age Diet: Based on In-Depth Studies of Human Ecology and the Diet of Man (1975)

• Loren Cordain, The Paleo Diet: Lose Weight and Get Healthy by Eating the Food You Were Designed to Eat (2002)

• Mark Sisson, The Primal Blueprint (2009)

• John Durant, The Paleo Manifesto: Ancient Wisdom for Lifelong Health (2013)

• Marlene Zuk, Paleofantasy: What Evolution Really Tells Us About Sex, Diet, and How We Live (2013)

Peer-Reviewed Research

• Mannheimer et al., "Paleolithic nutrition for metabolic syndrome: systematic review and meta-analysis," American Journal of Clinical Nutrition (2015)

• Jacobs et al., "Paleo Diets Still Lack Evidence," American Journal of Clinical Nutrition (2016)

• Journal of Nutrition (2016) — Paleolithic and Mediterranean diet pattern scores and association with inflammation and oxidative stress markers

• Anton et al., "How diets work: popular diet methods reviewed," Nutrients (2017)

• Genoni et al., "Long-term Paleolithic diet is associated with lower resistant starch intake, different gut microbiota composition and increased serum TMAO concentrations," European Journal of Nutrition (2019)

• Science of the Total Environment (2021) — Sustainability and health impacts of Paleolithic diets

• PMC, "The Paleolithic Diet" (2023) — Analysis of wild vs. domesticated meat fat content

Surveys & Reports

• Gallup Poll, "Snapshot: Few Americans Vegetarian or Vegan" (2018)

• UC Davis Nutrition Information Sheet (2020) — Calcium, Vitamin D, and bone health concerns

Other Sources

• Adrienne Rose Johnson, food historian — on Voegtlin's advocacy for mass slaughter of dolphins and tigers

• Hodson & Earle (2018) — Research on meat consumption, political ideology, and social dominance orientation

• Dr. Peter Ungar, University of Arkansas — paleontological research on human teeth and diet