This article is part of our Fad Diet series.
For those of you who have just joined us, we are taking a look at some of the most popular fad diets of the year. Last week we looked at the keto diet: a highly restrictive diet that limits carbs and increases fats. Keto is beneficial for some groups of people (studies involving people with type 2 diabetes and obesity) but does more harm than good in the long run. This week we are tackling the notorious Paleo diet, aka the “caveman” diet.
No doubt you’ve heard of this diet from ‘Paleo-pushing Pete’ (Evans), a well-known Australian celebrity chef. Paleo involves eating a diet modelled on that of our prehistoric human ancestors, specifically during the Palaeolithic era—which dates from 2.5 million to 10 000 years ago. Paleo food typically includes lean meats, fish, nuts, seeds, fruits and vegetables—foods typically obtained by hunting and gathering. As such, the diet restricts dairy products, legumes and grains, foods that became common when farming emerged about 10,000 years ago. It also avoids refined sugars, salt and highly processed foods in general (sounds quite healthy actually!).
The aim of the Paleo diet—as you’ve probably gathered (no pun intended)—is to go back to an eating plan closely resembling what early humans ate. But why, though? Y’all are happy enough using electricity and upgrading to the latest gadgets, so what’s wrong with modern food? (I mean apart from the fact that most things are highly processed, chock full of chemicals and additives, and unethical/unsustainable sourcing). The Paleo reasoning is that our human bodies are genetically mismatched to the post-farming modern diet, this idea is termed the discordance hypothesis.
Farming changed human diets, making dairy, grains and legumes staples. This late and rapid dietary change did not match with the body’s ability to adapt (according to the discordance hypothesis). And it is this mismatch that is thought to be the factor contributing to the prevalence of cardiovascular disease, diabetes and obesity.
Harmful or beneficial?
A main difference between the Paleo diet and other healthy diets, is that absence of dairy products, which are known sources of protein (to build muscle) and calcium (for bone growth and development), vitamins, and whole grains and legumes (good sources of fibre and great for your gut bacteria). Dietician Alex Nella at the University of California warns that a typical Paleo diet puts people at risk of calcium and vitamin D deficiencies.
In 2007, a study was performed on pre-diabetic patients with ischemic heart disease who were placed on one of two diets, a Paleo diet or a Mediterranean diet (focused on whole grains, low fat dairy) for 12 weeks. After 12 weeks, the Mediterranean group lost body fat and saw improvements in markers of diabetes. Interestingly, those in the Paleo group fared even better. They lost 70 per cent more body fat and also had normal blood sugar levels by the end of the study—which is a great result! A second study was performed, but instead of using people with an early and mild case of diabetes, the researchers used long-term diabetic patients. Researchers found that a Paleo diet did not ‘cure’ their diabetes, but it could improve it. Similarly, in 2009, researchers studied Paleo vs usual diet of nine non-obese, sedentary (inactive) lifestyle, healthy people and found that a Paleo diet improved blood pressure, insulin sensitivity and lipid levels. Many clinical trials have compared Paleo to other eating plans. Overall, the findings suggest that a Paleo diet may offer benefits including weight loss, better glucose tolerance, improved blood pressure and better appetite management.
However, other studies have found no significant differences in results when comparing Paleo to other diets. In a 2015 study involving 24 healthy male volunteers, no differences were found in glucose and insulin response between meals.
A caveat of most studies is macronutrient matching. In some studies, the Paleo group ate more protein compared to other diet groups. As we know, protein helps maintain lean mass and keeps us feeling satisfied by our meals. And so, Paleo may indeed be beneficial but without macronutrient matching, it’s hard to know for sure whether the benefits are directly due to the Paleo diet or other factors such as differences in macronutrients between diet groups.
The reality with Paleo, is that it is over-hyped and under researched. Despite the claims made by celebrities who swear by Paleo, it remains largely unsupported by current scientific evidence. Some aspects of Paleo may confer benefits through the intake of foods that are nutritious and healthy, but long-term effects of restricting major nutrients such as dairy, grains and legumes are not known. The key to unlocking good health, is moderation in everything and, a balanced and active lifestyle.
Not everyone is suited to the Paleo diet, for various reasons including kidney disease, cardiovascular disease and nutrient deficiencies. Please speak to a medical professional and do your research if you are thinking of going on a diet.