The Paleo Diet

What is the Paleolithic Diet?

This diet is a modern version of the traditional hunter-gatherer diet containing wild animals and plants which evolved during the Paleolithic era. The typical contemporary diet includes vegetables, fruit, nuts and seeds, insects, eggs, grass fed pasture raised meat (including offal), seafood, herbs and spices. Food can be eaten either raw or cooked. It excludes cereals and grains, legumes, dairy and salt as well as processed and refined sugars and fats. Alcohol is also prohibited on this diet. 

Macronutrient Composition

The Paleolithic diet is high in protein and usually low in carbohydrate (~23% of total energy intake). However sometimes versions of the diet which include root vegetables such as potatoes will result in a higher carbohydrate intake. This diet also has a lower energy density than the typical Western Diet. This means it contains less energy per gram of food.
The theory behind the diet

The key justification for the diet is that our genetics are adapted to this Palaeolithic diet and that there has been no change in human genetics since the dawn of agricultural development and the industrial revolution. It puts forward the argument that these two factors have greatly influenced the food supply and negatively impacted dietary intake and consequently health.

The Supporting Argument

· Compared to the Paleolithic diet, today’s energy dense diets with many processed and refined sugars and fats can lead to overeating, weight gain and the development of chronic disease. 

· Studies have demonstrated that carbohydrate restriction may help prevent obesity and type 2 diabetes as well as atherosclerosis (the build-up of fatty plaques in blood vessels). Being a mainly low GI diet, many of the included foods place less stress upon the pancreas to produce insulin, preventing gradual insulin insensitivity.

· The diet is high in fibre. Pre-agricultural diets were thought to exceed 100g/day (In Australia we recommend 25-30g/day and quite often the average person does not consume this much). Fibre is essential for optimal bowel health and keeps us fuller for longer, often preventing over consumption or quick sugar fixes.

· The diet is low in sodium, a key factor which can contribute to the decline of cardiovascular health. 

· For those with intolerances such as gluten or lactose intolerance this diet is appropriate to avoid symptoms and prevent future damage to organs within the body. For example for those with gluten intolerance this will cause small bowel damage and mal-absorption of nutrients.

The Argument Against

· The modern day version of the diet is unlikely to mirror the original Paleolithic diet as food for consumption today is not the same or as commonly available as wild animals and plants existing more than 10 000 years ago.

· There is evidence that Paleolithic societies used cereals as early as 23 000 years ago and potentially even as early as 200 000 years ago.

· Being so restrictive in its features, duplicating such a regimen is difficult and makes the diet potentially unsustainable in the long term.

· Banning particular foods can result in an inadequate intake of vitamins and minerals. Cutting out dairy can lead to an inadequate intake of calcium. Calcium is essential for maintaining bone strength. Breads and cereals are leading contributors to fibre, folate, niacin, thiamine, iron, zinc, magnesium and carbohydrate intake. These nutrients play vital roles in growth, immunity, brain function and energy levels. Vitamin D is another vitamin at risk whilst adhering to this diet.

· Greater intake of environmental toxins from a high intake of fish

· Our genetics have adapted to our modern day diet to some degree. For example alleles conferring lactose tolerance (lactose is a sugar found in dairy) increased dramatically in Europe a few years after animal husbandry. 

The Hard Evidence (Documented Studies)

· In a randomized crossover study a Paleolithic diet improved glycemic control and several cardiovascular risk factors compared to a diabetes diet in a cohort of patients with type two diabetes. However it is to be noted that the study was of a small sample size (less valid) and terminated early due to low participation rates.

· Another 2009 study comparing a normal western diet to a Paleolithic diet found compared with the usual diet subjects receiving the intervention diet experienced significant reductions in blood pressure, improved arterial dispensability, improved insulin sensitivity and significant reductions in total cholesterol, low-density lipoproteins, and triglycerides. This study also only had 9 participants (small sample size, again less validity).

· In Kitava, Trobriand Islands a study was conducted and noted the absence of cardiovascular disease and associated risk factors among 2,300 inhabitants (6% of which were 60–95 years old) as well as among the remaining 23,000 people in the Trobriand Islands. Yam, sweet potato, taro, and fruit were staple foods while grains, dairy, refined fats, and sugar were absent. The study supports the notion that a high-carbohydrate intake is not a problem in itself but perhaps today’s modern processed foods play a defining role.

· Studies have also found evidence that when trialed a ‘‘Paleolithic" diet was more satiating, such that the meals gave a feeling of fullness at a lower level of energy intake

 My opinion

I do have some concerns about this diet, although conversely I also appreciate some of its underlying principles. There is a strong evidence base that cutting out essential nutrients such as calcium most commonly found in dairy foods can lead to diseases such as osteoporosis later in life. Grains and cereals contribute to achieving recommended vitamin and mineral intakes, with their fibre content influential in maintaining optimal bowel and gastrointestinal function. Such a strict diet and one which truly reflects a genuine hunter gatherer diet is also going to be hard to maintain. Getting back to basics it’s not rocket science, cut out products containing sodium, refined sugar and processed fat (particularly saturated and trans fats) and most definitely your health with benefit. Follow a varied diet with 5 serves of vegetables and 2 serves of fruit a day. A low carbohydrate diet is not recommended. Carbohydrates are an essential fuel for our body, as long as they are of the right quality (of a low glycaemic index) and quantity (provide 45-65% of our energy requirements). 

 References

David C. Klonoff, M.D., FACP (2009), The Beneficial Effects of a Paleolithic Diet on Type 2 Diabetes and Other Risk Factors for Cardiovascular Disease, J Diabetes Sci Technol. 3(6): 1229–1232

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):947–955

Lindeburge Staffan (2012) Paleolithic Diets as a Model for Prevention and Treatment of Western Disease, AMERICAN JOURNAL OF HUMAN BIOLOGY 24:110–111