Paleolithic diet (paleo diet)

What is The Paleo Diet?

The Paleolithic diet is also known as 'The Paleo Diet®', the 'Caveman diet', the 'Stone Age diet' and the 'Hunter-gatherer diet'.

The fundamental concept of the diet is the belief that humans should eat unprocessed, natural, fresh foods to reflect the diet of our hunter-gatherer ancestors who were alive during the Paleolithic era. This era began 2.5 million years ago and ended 10,000 years ago.

The diet comprises foods that need to be 'hunted' or fished, such as meat and seafood, and those that can be 'gathered' such as fruits and vegetables. It excludes foods that were not available to humans at that time and some which - although available - do not meet the fundamental nutritional characteristics of the diet (see 'Paleo Diet Food List' below).

Purpose of the paleo diet

Supporters of the Paleolithic diet believe that such foods are better for us because this is what our body has been genetically adapted to eat. They argue that our genetics have not changed much since Paleolithic times.

They believe that the human body and metabolism have not been able to keep up with the advances in agriculture and food manufacturing processes that have taken place. So, the body is not adapted well to coping with the modern human diet rich in dairy products, processed foods and grains. They believe that adopting a Paleolithic diet provides beneficial effects to health and well-being.

There is some scientific evidence to support this. Studies have found that in some cultures - such as Aboriginal Australians - the incidence of obesity, diabetes and heart disease only increased when processed foods were introduced to their diet.

Recent research suggested that risk factors for type 2 diabetes and cardiovascular disease reduced on a Paleolithic diet, but the authors felt more work was needed in this area.

Paleo Diet food list

There are seven fundamental characteristics that make up The Paleo Diet®:

1. It has a high protein content. Protein foods such as meat, meat products and seafood are the diet staples.

2. Carbohydrate intake is low. The carbohydrates that are eaten are those with a low glycaemic index. Non-starchy fresh fruits and vegetables make up the main carbohydrate source, providing between 35-45% of daily calorie intake. These foods have a low glycaemic index. This means that when eaten, they are digested and taken up (absorbed) more slowly by the body, causing less of an impact on blood sugar levels. Note: potatoes are starchy carbohydrates and so should not be eaten on the diet.

3. Fibre intake is high. The main sources of dietary fibre in The Paleo Diet® are from non-starchy fruits and vegetables rather than from whole grains and refined grains.

4. There is a high fat content. Fats that are eaten should be mostly mono-unsaturated and polyunsaturated rather than saturated fats and trans fats.

5. Potassium salt intake is high and sodium salt intake is low. The unprocessed, fresh foods eaten on the diet contain higher proportions of potassium salt versus sodium salt.

6. There is a dietary acid and alkaline balance provided by the diet. Eating plenty of alkaline-producing foods such as fruit and vegetables in the diet achieves a balance with acid-producing foods such as meat and fish.

7. There is a high intake of vitamins, minerals, plant phytochemicals and antioxidants.

What to eat

• Fresh fruit and vegetables.

• Fish and seafood.

• Meat that has been produced from grass-grazing animals.

• Eggs.

• Nuts and seeds.

• Olive, walnut, flaxseed, macadamia, avocado and coconut oils.

What to avoid

• Cereal grains (which means no pasta, bread or rice).

• Dairy foods.

• Refined sugar.

• Legumes, including beans and peanuts.

• Potatoes.

• Processed foods.

• Salt.

• Refined vegetable oils.

What to drink

• Water.

• Sparkling water.

• Soda water, seltzer, club soda.

• Kombucha or other fermented non-dairy drinks.

• Herbal caffeine-free teas.

What are the proposed health effects of The Paleo Diet?

Claims are that The Paleo Diet® can improve health by reducing the risk of:

• Heart disease.

• Type 2 diabetes.

• Chronic degenerative diseases.

And that it can also:

• Enable weight loss.

• Slow or reverse the progression of autoimmune disease.

• Improve sleep.

• Increase energy.

• Improve acne.

• Increase athletic performance.

• Increase libido.

• Improve mental clarity and outlook.

What is the evidence behind a Paleolithic diet?

In general, the studies and research that have looked into Paleolithic diets so far have only involved very small numbers of people. Many have not involved long-term follow-up or control subjects (a group of subjects closely resembling the group being studied who are acting as a comparison).

A study published in 2014 brought media attention because it did include control subjects. It also involved slightly larger numbers of people and followed up participants for a little longer. The study involved a group of 70 women who had gone through the menopause. The women were split into two groups: a group who followed a low-fat Nordic diet that did not exclude any food group (the control group), and a group who followed a Paleolithic diet. The two groups of women were followed up for two years.

Even though those who were following a Paleolithic diet had lost more weight at six months, at two years weight was the same in both groups. There was a difference in triglyceride levels between the two groups at two years. (Triglycerides are a certain type of fat thought to be involved in heart disease). The women on the Paleolithic diet had better triglyceride levels at two years. However, the women in the control group still had levels of triglycerides that were thought to be safe.

The bottom line is that it is very difficult to draw specific conclusions from the studies carried out on a Paleolithic diet so far. Studies involving larger numbers of people that look at the more long-term health effects are needed before health benefit claims of Paleolithic diets can be backed up.

Paleo diet benefits

Making fresh, unprocessed foods the basis of what you eat (as in a Paleolithic diet) does mean that you will stay away from processed foods. Processed foods are generally regarded as those foods that have been treated or prepared using some manufacturing process - for example, by adding preservatives or artificial flavourings.

Processed foods tend to be high in calories and also often high in salt. We do know that too much salt in your diet increases your risk of developing high blood pressure, which itself can lead to heart disease and stroke.

Also, once you have grasped the basic concept, a Paleolithic diet is relatively easy to follow. It does not involve counting calories, weighing foods, etc.

Paleo diet risks and downsides

As discussed above, Paleolithic diets do not have plentiful research and scientific evidence to back them up at present.

The current UK Department of Health advice is that people should not eat more than 70 g of red or processed meat daily because of an increased risk of bowel cancer. Critics of Paleolithic diets would say that the high meat content of such diets goes against this advice.

The fact that the diet does not allow consumption of dairy products is also criticised by some nutrition experts, including the British Dietetic Association. Eliminating key food groups such as dairy products from your diet raises the chance of nutritional deficiencies.

A major concern with Paleolithic diets is that they may lead to calcium deficiency because of the exclusion of dairy products. Calcium is needed for healthy teeth and bones and is also involved in blood clotting and muscle contraction.

There is also evidence that whole grains reduce the risk of heart disease, stroke, type 2 diabetes and some cancers. Paleolithic diets exclude grains and so some nutrition experts are concerned about this.

Finally, because Paleolithic diets involve eating meat, they are expensive and cannot be followed by vegetarians.

What other options are there to lose weight?

Other types of diet are available - for example:

• Dukan diet.

• Atkins diet.

• 5:2 diet.

There are other ways of changing your diet and altering your lifestyle to help you lose weight, such as increasing your physical activity.

You may find other leaflets in this series helpful including:

• Obesity and weight loss.

• Weight reduction.

• Orlistat (Weight loss medicine).

• Weight loss surgery.