The paleo diet encourages the consumption of foods based on the eating habits of our ancestors from the Paleolithic period, between 10,000 and 2.5 million years ago.
Whole foods such as seafood, meat, root vegetables, seeds, fruits and nuts are eaten on the assumption that prior to the introduction of agriculture and industry, humans were hunter-gatherers foraging for berries, hunting animals with spears and nets, learning to fish and scavenging for meat from animals that other predators had killed.
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Followers of the paleo diet do not consume processed foods generated by agriculture and industry such as white bread, packaged meats, sugary cereals and cheese. These foods provide less protein , iron and fiber than the unprocessed equivalents. They are often also full of sodium and preservatives, some of which may increase the risk of cancer and cardiovascular disease.
The first article to examine the human diet in terms of evolution was published in New England Journal of Medicine in 1985. Boyd Eaton and Melvin Konner looked at the evidence for diet s of modern hunter-gatherers. They concluded that all food items were real foods that had not been processed. Those foods had a significantly higher nutrient content than foods produced through industrial and agricultural systems. They also concluded that an ancestral diet is not necessarily healthy, but should be a model for what is considered healthy.
Currently, clinical evidence does support that eating a diet rich in animal meats, starchy plants, leaves, fruits , nuts , seeds and vegetables improves health. In a 2015 review and meta-analysis by Manheimer et al, published in the American Journal of Clinical Nutrition, compared with individuals on a control diet based on US diet guidelines, a paleo-style diet led to improved symptoms of metabolic syndrome. O ther studies and case reports on individuals show health improvements when a paleo-style diet is adopted. They provide evidence that so long as people adhere to a species-appropriate diet, the remaining factor to determine metabolic health is the degree by which components in the diet are processed. The common factor is the quality of the macronutrients rather than the amount of macronutrients (whole foods versus processed foods) and whether or not the foods are species appropriate.
Ancestrally appropriate diets such as the paleo diet are often criticized in research conducted by the food industry. Such studies are complicated by confounding factors, with data that is inaccurate due to the self-report surveys that evidence is usually acquired from. These studies should only be used as a starting point for making hypotheses to be clinically researched, rather than being treated as a reliable information source.
Reviewed by Catherine Shaffer, M.Sc.
- Fenton, T. R., & Fenton, C. J. (2016). Paleo diet still lacks evidence. American Journal of Clinical Nutrition,104(3), 844-844. doi:10.3945/ajcn.116.139006, http://ajcn.nutrition.org/content/104/3/844.extract
- Manheimer, E. W., Zuuren, E. J., Fedorowicz, Z., & Pijl, H. (2015). Paleolithic nutrition for metabolic syndrome: systematic review and meta-analysis. American Journal of Clinical Nutrition,102(4), 922-932. doi:10.3945/ajcn.115.113613, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588744/
- Scientific American, How to Really Eat Like a Hunter-Gatherer: Why the Paleo Diet Is Half-Baked, www.scientificamerican.com/.../
- The Evolution Institute, On Junk Diets and Junk Science: What’s the evidence for and against the paleo diet? evolution-institute.org/.../