What is a Paleo diet?

A Paleo diet is a pattern of eating that attempts to mimic the diet of our Paleolithic ancestors. The basic premise is what humans ate in pre-agricultural times is the diet best suited to our genetic make-up.

What is the typical macronutrient distribution in Paleo diets?

Today’s Paleo diets provide approximately 20% of calories from carbohydrates,

30% of calories from protein and 50% of calories from fat.

What did people in the Paleolithic period actually eat?

Pre-agricultural people ate wild plants, animals, fish and insects. The balance of these foods varied with timeframe, location, season, gathering and hunting skills, tools and culture. Nutritional anthropologists have provided detailed estimates of macro- and micronutrient intakes. Macronutrient intakes were estimated at 35-65% of calories from carbohydrates, 30% of calories from protein, and 20-35% of calories from fat. Many of the nutrients associated with plant foods were extraordinarily high in Paleolithic diets. For example, fiber was estimated at 70-150+ grams, vitamin C at 500 mg, calcium at 1000+ mg, and potassium at 7,000 mg. These estimates significantly exceed usual intakes of people who consume 100% plant-based diets today. This raises an interesting question:

What comes closer to true Paleolithic diets – a 100% plant-based diet or a “Paleo” diet?

Analyzing recommended Paleo and 100% plant-based menus of today, the 100% plant-based menus come much closer to true Paleolithic intakes than do today’s Paleo menus. Today’s Paleo menus come closer to true Paleolithic diets for 3 out of 16 nutrients analyzed, including protein, Vitamin A and zinc. The 100% plant-based menus come closer for the remaining 13 nutrients. Why? Meat and vegetables consumed today were not available in Paleolithic times and bear little resemblance to those eaten by pre-agricultural populations. Wild meat is much lower in total and saturated fat, and higher in omega-3 fatty acids than meat from domestic animals. It was free of antibiotics, added hormones, and environmental contaminants. Wild plants are higher in fiber, more concentrated in nutrients, and lower in sugar than domestic plants. In addition, Paleo devotees focus on eating enough meat to get 30% of calories from protein, as opposed to eating enough plant foods to get 70-150+ g fiber, 7,000+ mg potassium, 1,000 mg calcium or 500 mg vitamin C. 

What are the common claims of Paleo proponents?

Paleo diets are said to promote weight loss, increase energy, improve muscle tone and skin, reduce inflammation, improve mood, and dramatically reduce chronic disease risk.

Is there any evidence that Paleo diets are effective?

Yes, there are many short term trials that have reported weight loss, increased satiety, improved blood lipids, lower fasting glucose, better insulin sensitivity, reduced inflammation and decreased blood pressure. The diets in these clinical trials are generally well designed to replicate true Paleolithic diets. These diets typically feature very lean meat from free-range animals and wild fish, and generous amounts of vegetables and fruits. They eliminate highly processed foods, including refined grain products, simple sugars, concentrated fats and oils, fast foods, fried foods, processed meats, dairy products and alcohol. So, it is not surprising that they produce favorable results. Many popular Paleo diets are less well designed and include high fat meats, processed meats, concentrated fats and oils, and added salt. Results may not be as favorable with these diets.

Are there concerns about Paleo diets long term?

Yes. Today’s Paleo diets are very high in meat. People eating 30% of calories from protein, with 80% of the protein from animal products, will be consuming 16 oz of meat per day on a 2,000 calorie diet and 22 oz on a 2,800 calorie diet. Meat intake is strongly associated with dysbiosis (unhealthy gut microbiome), diabetes, heart disease, some forms of cancer, and increased mortality. This is because meat is a significant source of saturated fat, cholesterol, Neu5Gc (an inflammatory molecule), chemical contaminants, endotoxins (inflammatory breakdown products of dead bacteria), and nitrosamines (processed meat). A 2019 report in the European Journal of Clinical Nutrition reported that people eating Paleo diets had a lower level of healthful colon bacteria and double the levels of TMAO (an atherogenic compound) in the blood than people eating a conventional diet. 

Why choose a whole food plant-based diet over a Paleo diet?

In addition to being high in meat, typical Paleo diets eliminate legumes and whole grains. Meat is associated with increased mortality; legumes and whole grains are associated with reduced mortality. These plant foods are staples in the diets of Blue Zone residents – places where people live the longest, healthiest lives on the planet. Many studies comparing similar, health conscious meat eaters with people eating plant-based diets have reported reduced disease risk in those eating plant-based. The question that we must ask ourselves is this: How can humans best adapt to their current environment to sustain a growing population on a shrinking planet? Paleo diets dramatically increase consumption of meat, poultry, fish and eggs. This means diets with a far higher carbon footprint. If everyone on the planet ate Paleo, Dr. David Katz estimated we would need 15 planet earths to sustain the current population. In addition, the animal food industry would intensify their operations to satisfy the demand for meat, and the consequences for animals would be unthinkable.

Can a Paleo diet be plant-based?

Yes, it is possible to design a plant-based Paleo diet. However, this diet would attempt to replicate actual Paleolithic intakes as opposed to intakes of people following a new Paleo diet. Hence, one would aim for a diet rich in protein (about 20% of calories), moderate in fat (20-30% of calories) and relatively high in whole food carbohydrates (50-60%). The diet would provide at least 70 grams of fiber per day from a variety of plant foods, including legumes, intact grains, vegetables, fruits, nuts, and seeds. Protein-rich foods such as tofu, tempeh, legumes and seeds, would be featured in most meals.

Are national and international nutrition authorities recommending plant-based or Paleo?

There is strong, consistent evidence that whole plant foods are protective to health, and heavily processed foods, fast foods, fried foods, and meat, especially processed meat, are damaging to health. Both national and international dietary guidelines now reflect this knowledge. For example, in the World Health Organization’s 12 steps to healthy eating, step 1 is “Eat a nutritious diet based on a variety of foods originating mainly from plants, rather than animals.” Many countries now include guidelines to eat more plant-based diets, including Canada, Germany, Brazil, Qatar and the UK. The United States Dietary Guidelines Scientific Advisory Committee clearly stated that “…a dietary pattern that is higher in plant-based foods, such as vegetables, fruits, whole grains, legumes, nuts, and seeds, and lower in animal-based foods is more health promoting and is associated with lesser environmental impact than is the current average U.S. diet.” In the widely distributed EAT Lancet Commission report of 2019, the universal health reference diet was described as one that increases healthy foods (vegetables, fruits, whole grains, legumes and nuts), and decreases unhealthy foods (red meat, sugar and refined grains).

Selected References

  1. Abete I, et al. Association between total, processed, red and white meat consumption and all-cause, CVD and IHD mortality: a meta-analysis of cohort studies. Br J Nutr. 2014;112(5):762-75.

2.       Davis B, Melina V. Becoming Vegan: Comprehensive Edition. The Book Publishing Company, Summertown TN. 2014.

3.       Eaton SB, Eaton SB 3rd, Konner MJ. Paleolithic nutrition revisited: a twelve-year retrospective on its nature and implications. Eur J Clin Nutr. 1997;51(4):207-16.

  1. FAO FCRN. Plates, pyramids, planets. University of Oxford. 2016. http://www.fao.org/3/a-i5640e.pdf
  2. Frassetto LA. Established dietary estimates of net acid production do not predict measured net acid excretion in patients with Type 2 diabetes on Paleolithic-Hunter-Gatherer-type diets. Eur J Clin Nutr. 2013;67(9):899-903.

6.       Genoni A, et al. Compliance, Palatability and Feasibility of PALEOLITHIC and Australian Guide to Healthy Eating Diets in Healthy Women: A 4-Week Dietary Intervention. Nutrients. 2016;8(8).

  1. Genoni A, et al. Long‑term Paleolithic diet is associated with lower resistant starch intake, different gut microbiota composition and increased serum TMAO concentrations. Eur J Clin Nutr. July 5, 2019.

8.       Jönsson T, et al. Subjective satiety and other experiences of a Paleolithic diet compared to a diabetes diet in patients with type 2 diabetes. Nutr J. 2013;12:105.

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  3. Larsson SC, Orsini N. Red meat and processed meat consumption and all-cause mortality: a meta-analysis. Am J Epidemiol. 2014;179(3):282-9.
  4. Levine ME. Low protein intake is associated with a major reduction in IGF-1, cancer, and overall mortality in the 65 and younger but not older population. Cell Metabolism. 2014;19:407-17.13.   Masharani U, et al. Metabolic and physiologic effects from consuming a hunter-gatherer (Paleolithic)-type diet in type 2 diabetes. Eur J Clin Nutr. 2015;69(8):944-8.14.   Otten J, et al. Benefits of a Paleolithic diet with and without supervised exercise on fat mass, insulin sensitivity, and glycemic control: a randomized controlled trial in individuals with type 2 diabetes. Diabetes Metab Res Rev. 2017;33(1).
  1. Song M et al. Association of Animal and Plant Protein Intake With All-Cause and Cause-Specific Mortality.JAMA Intern Med. 2016;176(10):1453-1463.
  2. Wang X, et al. Red and processed meat consumption and mortality: dose-response meta-analysis of prospective cohort studies. Public Health Nutr. 2015;6:1-13.
  3. WHO Europe. CINDI Dietary Guide. 2000. http://www.euro.who.int/__data/assets/pdf_file/0010/119926/E70041.pdf

18.   Willett W, et al. Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. Lancet. 2019;393(10170):447-492.

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