Is It Time To Leave The Paleo Diet In The Past?

This diet plan encourages people to mimic a diet that would be similar to what our prehistoric ancestors might have been consuming, which would mean avoidance of dairy products, cereals, pulses, and processed sugars (anything processed or refined actually) while focusing on consuming more vegetables, fruits, nuts, and pasture-raised meats as well as wild-caught seafood. Proponents of this diet suggest that following the Paleo Diet will help one to drop unwanted weight and reduce the risks of chronic diseases. 

This diet plan is not new as it can be traced back to the 1950s, but most of the recent popularity is linked to a book first published in 2001 that was written by Loren Cordian called “The Paleo Diet: Lose Weight and Get Healthy by Eating the Food You Were Designed to Eat.” Since this publication, several million people have adopted this diet, and a multi-billion dollar industry has been developed along with it which includes premium-priced foods and a “questionable certification program”. 

The Paleo Diet may have many followers, but clinical research has yet to substantiate the suggested health benefits claimed by its proponents. One of the claims is that this diet outperforms conventional recommended diets for losing weight in the medium to long term. However the only published multi-year study to evaluate the Paleo Diet’s impact on weight loss does not support this claim, in fact, this study found that it was no more effective than following the Nordic countries’ official recommendations for nutrition after 2 years. 

Claims have also been made about the Paleo Diet’s impact on chronic disease, but a recent review of this diet’s impact on Type 2 diabetes found the studies to be “inconclusive”. Another study reported that following this diet resulted in a higher relative abundance of gut bacteria that produces a chemical that is associated with cardiovascular disease, this finding also does not support the claim of this diet in reducing the probability of developing chronic diseases. 

Mark Collard, who is a Canada Research Chair in Human Evolutionary Studies and a Professor of Archaeology; and Amalea Ruffett who is a Ph.D. student in Archaeology, at Simon Fraser University believe that the health claims of the Paleo Diet are not supported by clinical research because the “diet is based on a flawed premise and faulty data”. 

As evolutionary anthropologists, they believe that the idea underlying the Paleo diet is that the global ongoing and increasing rates of obesity and the associated diseases are the result of a mismatch between the foods that we consume and the foods that our species evolved to actually consume. This mismatch argument suggests that this is a consequence of there not being enough time since agriculture appeared roughly 12,000 years ago for evolution to adapt our species to deal with high carbohydrate, low protein diets or to even process GMO and domesticated foods. The argument seems reasonable as evolution is perceived to be a very slow process, but this perception is not supported by research on diet-related genes. 

Research on the continued ability to produce the enzyme lactase as an adult illustrates this, as lactase enables humans to digest the milk sugar lactose, making lactase persistence useful for a diet that includes dairy products. Lactase persistence is found in a few global regions, such as Europe where Ancient DNA research indicates that it is less than 5,000 years old. Other analysis of genetic data from African populations found evidence of recent adaptation in a family of genes connected with metabolizing alcohol wherein natural selection operated within the last 2,000 years. Research such as this further illustrates that the mismatch argument to following the Paleo Diet is not supported by genetic studies, as these studies demonstrate that evolution can produce diet-related adaptations in less time than what has elapsed since the appearance of agriculture. 

The evolutionary anthropologists also believe that there is an issue with this diet’s recommendations for the contributions of protein, carbohydrate, and fat macronutrients to a person’s diet. This diet suggests aiming for a diet that consists of 19-36% protein, 22-40% carbohydrates, and 28-58% fat, by energy. However, this recommendation makes the Paleo Diet lower in carbohydrates and higher in protein than conventionally recommended diets such as those that are promoted by the United States Department of Agriculture and Health Canada. 

The recommended Paleo Diet macronutrients are based on a study that estimated the percentages for over 200 hunter-gather groups, but recently an issue has been revealed with that study. The issue lies in the macronutrient values used for plant foods; several sets of macronutrient values were used for animal foods but only one set of values was used for plant foods, obtaining the plant data from an analysis of foods that are traditionally eaten by Indigenous Australians. 

The recent study evaluated the effects of this decision with 2 plant macronutrient datasets that both consisted of values for plants consumed by hunter-gatherers across several continents. This multi-plant multi-continent data resulted in significantly different macronutrient estimates which produce macronutrient ranges of 14-35%protein, 21-5% carbohydrates, and 12-58% fat by energy which are wider than those recommended in the Paleo Diet. These wider ranges also overlap those that are recommended by the United States Department of Agriculture and those from Health Canada. This overlap with government-approved macronutrient ranges casts even further doubt on the idea that the Paleo Diet is healthier than conventionally recommended diets. 

Based on these findings the evolutionary anthropologists are not surprised that the purported health benefits of the Paleo Diet have not been supported by clinical studies because the macronutrient recommendations are not scientifically robust, and the rationale for adopting this diet is not supported by available research. They conclude an article published in the Conversation by stating that  “The Paleo Diet has been a worthwhile experiment, but at this point it seems likely that people following it might just be wasting money. Conventional, government-recommended diets offer comparable outcomes at a lower cost. In our view, it’s time to leave the Paleo Diet in the past.”