What is the paleo diet?
One of the most well known mainstream diets, the paleo diet is designed to emulate the eating habits of our hunter-gatherer ancestors. The rationale behind it is that they did not suffer with the same non-communicable diseases, such as type 2 diabetes and cardiovascular disease, that are so prevalent in today’s society.
Those who adhere to and promote the paleo diet suggest that modern diets that are result of advanced farming practices are not compatible with our bodies, this is known as the discordance hypothesis.
The paleo diet promotes consumption of unprocessed foods, from both animal and plant sources, and eliminates processed foods and refined sugar.
The original version, depicted in the book ‘The Paleo Diet’ by Dr Loren Cordain, also requires avoidance of grains and dairy, though some of the more modern iterations have incorporated these in some forms, such as rice.
What does the diet look like?
Foods that are avoided on the paleo diet are sugar, soft drinks, processed foods, legumes, artificial sweeteners, vegetable oils, margarine, trans fats, and, depending on the version of the diet, most dairy products and grains.
Foods that are encouraged are vegetables, fruits, nuts, herbs, spices, seeds, meat, eggs, fish, healthy fats and oils. Some of the more recent versions of the diet also allow modern foods that the author believes to be healthy, examples include grass-fed butter, non-gluten grains such as rice, and bacon from pasture raised pigs. The paleo diet also encourages drinking lots of water and daily exercise.
A typical day following the paleo diet may look like this;
Breakfast: Scrambled egg with vegetables, and a piece of fruit.
Lunch: Chicken salad, with a handful of nuts on the side.
Dinner: Burgers fried in butter without a bun, with vegetables and salsa.
The Benefits and Downsides
The paleo diet promotes increased consumption of healthy foods such as vegetables, nuts, and fish, which will have a positive impact on the individual’s health. Furthermore, eliminating highly processed foods from the diet is likely to promote weight loss and better cardiometabolic health.
Similarly to all mainstream diets, the paleo diet appeals to those who would like to lose weight and find it easier to adhere to diets with clear rules and a more rigid structure. Another factor in its popularity is that the rationale behind the diet is easily explained and sounds plausible.
With regards to the premise of paleo diet, there are several holes in the discordance hypothesis. Research suggests that our diets may have included grains as long as 30,000 years ago, long before farming began. Similarly, other factors, such as food availability and climate, would have influenced our nutritional needs, therefore the paleo diet is likely to put too much focus on the impact of farming.
The most obvious difference between the paleo diet and long established healthy diets, such as the Mediterranean diet, is the avoidance of wholegrains and legumes, which are an important source of fibre, vitamins, and nutrients.
These foods are also typically much more affordable than key elements of the paleo diet, such as nuts and meat, which make this diet difficult to follow on a budget. Many paleo recipes also use coconut oil, a product that has seen a huge increase in popularity in recent years, however the literature suggests coconut oil is not the health product many claim it to be. This was extensively discussed in this review.
What does the research say?
Unlike many mainstream diets, there are several studies looking at the efficacy of the paleo diet on different health outcomes.
A short-term study comparing a paleo diet to a diet based on the American Diabetes Association recommendations, showed both groups had improvements in metabolic measures, but a greater improvement in glucose control and lipid profiles was observed in the paleo group. The full study can be found here.
This is not an isolated study, a similar result was also seen in research investigating the paleo diet and glucose tolerance in individuals with heart disease.
A study looking at the impact of short-term adherence to the paleo diet in healthy students also demonstrated weight loss, reduced weight circumference and systolic blood pressure.
Though the above studies would suggest strong evidence for the paleo diet, there are important limitations to consider.
Studies of the paleo diet are small, with low numbers of participants reducing the confidence in any findings. The studies are also short-term, and there is a notable lack of long term studies demonstrating the superior effects of the paleo diet when compared to a healthy control diet.
The version of the paleo diet typically used in research is also the original, and therefore restricts salt and dairy, and puts a strong emphasis on consuming lean meats. Modern versions of the paleo diet can look quite different to this, with many suggesting recipes for ‘healthy’ alternatives to processed foods, such as cheesecake, that contain high amounts of fruit sugar, honey, or maple syrup.
Overall it is likely that adherence to the paleo diet will help to lose weight and improve other biomarkers of disease, primarily through the elimination of processed foods and increased consumption of healthy foods.
However, it is well documented in the literature that these effects can also be achieved through any healthy, balanced diet based on lots of fruits and vegetables, and complimented by regular exercise.
Therefore, following a strict paleo diet is arguably unnecessary, and instead of promoting one diet as a ‘fix’ for diet related disease, taking steps towards diets generally much higher in healthy components and lower in processed foods, that work for each individual, is likely to be more effective and sustainable.