Paleo and Primal Style Diets
The premise of the paleo diet is that genetically we haven’t changed much since the time of the earliest humans. It has been said that “From a genetic standpoint, humans living today are Stone Age hunter-gatherers displaced through time to a world that differs from that for which our genetic constitution was selected”.1
Hunter-gatherer populations such as the Inuit, Australian Aboriginals, Hadza and others have until recent times lived relatively healthily and with a significant absence of the metabolic disorders of obesity and diabetes that plague the modern, western world.2-5
The ‘modern’ Paleo diet seeks to emulate these traditional hunter-gatherer diets by eliminating foods that are abundant in the modern diet but that were not present (in large amounts) in the diets of most hunter-gatherers. There are many variations on the Paleo theme and most people now follow some iteration of Paleo that could differ from the original template. For example, many now would classify their diet as ‘Primal’, a style of nutrition quite diverse but typically like Paleo; but with the addition of some dairy and occasionally sprouted legumes and even occasional grains.
The following table describes Paleo food choices.
Table 1. Paleo food table. By the author
Did Palaeolithic man really eat like that?
Critics of the Paleo diet point to the lack of consistency in hunter-gatherer diets. In other words, there is no ‘one true’ hunter-gatherer diet. An analysis of 229 hunter-gatherer diets from around the world found a high variance in carbohydrate intake (approximately 3%-50% of daily calories). However, the authors noted that carbohydrate intake in almost all hunter-gatherer populations is lower than that currently recommended for health,6 and it’s fair to say that all hunter gatherer populations have an absence of refined and processed foods! It’s also interesting to note that many critics of real-food based diets like Paleo are advocates for the Mediterranean Diet, and yet there is no ‘one’ Mediterranean Diet either. It is more important to look at either diet (because they are both great!) not as rigid prescriptions of certain foods for all people, but instead a compendium of available foods from which to choose.Did Palaeolithic man really eat like that?
Is Paleo Safe?
Much of the criticism of Paleo diets (especially for women) came from the assumption that a Paleo diet is extremely low in carbohydrate and that this might negatively affect thyroid status or cause other hormone imbalances. However, the Paleo diet isn’t by nature low in carbohydrates as it can include appreciable carbohydrate from sweet potato, yams, vegetables, berries and some fruit, which would be more than adequate for most women. But, even if a low-carb version of Paleo is applied, there is no good reason to think that the diet would necessarily affect hormone levels adversely. A severely carb-restricted Paleo diet could affect hormone levels in some women. Carbohydrate restriction can increase cortisol levels, one of our major stress hormones, (although this hasn’t been noted in the existing work on the Paleo diet) and reduce levels of the sex hormones (especially testosterone). This cortisol to free testosterone ratio is a key marker of fatigue syndromes. It is important to note that much of these distortions occur in the transition phase to a lower carbohydrate diet, but typically do not last if one becomes sufficiently ‘fat adapted’ or produces (or ingests) enough ketones to adequately supply additional fuel for neurons.
While critics may also point to a relative paucity of research on diets that emphasise whole, unprocessed foodstuffs (such as ‘The Paleo Diet’), there is, in fact, emerging and compelling evidence for the beneficial effects of real-food diets and Paleo itself has a growing body of evidence which suggests compelling benefits including:
- Better satiety than ‘best-practice’ dietary guidelines,7 best-practice diabetic meal plan,8 or the Mediterranean Diet.9
- Improved cholesterol profiles.10, 11
- Fat loss,12 even when eating ad libitum (eat as much as you desire).13
So, with low-carb, keto is a great way to go…but there are many ways to skin a cat and different variety of low-carb may be best for you!
- Eaton SB, Konner M, Shostak M. Stone agers in the fast lane: Chronic degenerative diseases in evolutionary perspective. The American Journal of Medicine. 1988;84(4):739-49.
- Sinclair HM. The Diet of Canadian Indians and Eskimos. Proceedings of the Nutrition Society. 1953;12(01):69-82.
- O’Dea K. Westernisation, insulin resistance and diabetes in Australian aborigines. Med J Aust. 1991;155(4):258-64.
- O’Keefe JJH, Cordain L, Harris WH, Moe RM, Vogel R. Optimal low-density lipoprotein is 50 to 70 mg/dlLower is better and physiologically normal. Journal of the American College of Cardiology. 2004;43(11):2142-6.
- O’Dea K. Westernization and non-insulin-dependent diabetes in Australian Aborigines. Ethn Dis. 1991;1(2):171-87.
- Ströhle A, Hahn A. Diets of modern hunter-gatherers vary substantially in their carbohydrate content depending on ecoenvironments: results from an ethnographic analysis. Nutrition Research.31(6):429-35.
- Bligh HF, Godsland IF, Frost G, Hunter KJ, Murray P, MacAulay K, et al. Plant-rich mixed meals based on Palaeolithic diet principles have a dramatic impact on incretin, peptide YY and satiety response, but show little effect on glucose and insulin homeostasis: an acute-effects randomised study. Br J Nutr. 2015;113:574-84.
- Jönsson T, Granfeldt Y, Lindeberg S, Hallberg A-C. Subjective satiety and other experiences of a Paleolithic diet compared to a diabetes diet in patients with type 2 diabetes. Nutrition Journal. 2013;12:105.
- Jonsson T, Granfeldt Y, Erlanson-Albertsson C, Ahren B, Lindeberg S. A paleolithic diet is more satiating per calorie than a mediterranean-like diet in individuals with ischemic heart disease. Nutr Metab (Lond). 2010;7:85.
- Masharani U, Sherchan P, Schloetter M, Stratford S, Xiao A, Sebastian A, et al. Metabolic and physiologic effects from consuming a hunter-gatherer (Paleolithic)-type diet in type 2 diabetes. Eur J Clin Nutr. 2015.
- Frassetto LA, Schloetter M, Mietus-Synder M, Morris RC, Jr., Sebastian A. Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet. Eur J Clin Nutr. 2009;63(8):947-55.
- Mellberg C, Sandberg S, Ryberg M, Eriksson M, Brage S, Larsson C, et al. Long-term effects of a Palaeolithic-type diet in obese postmenopausal women: a 2-year randomized trial. Eur J Clin Nutr. 2014;68(3):350-7.
- Ryberg M, Sandberg S, Mellberg C, Stegle O, Lindahl B, Larsson C, et al. A Palaeolithic-type diet causes strong tissue-specific effects on ectopic fat deposition in obese postmenopausal women. Journal of Internal Medicine. 2013;274(1):67-76.
About the author
Cliff Harvey is an author, researcher, and clinician. He is considered one of the pioneers of low-, and lower-carb nutrition in New Zealand, having first begun working with and prescribing them in the 1990s. He is the founder of The Holistic Performance Institute, a graduate college that specialises in providing scientifically valid, holistic health and nutrition education. Cliff is also a researcher and doctoral candidate in nutrition, specialising in ketogenesis at AUT University.
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