What is a paleo diet and should I try it?

The paleolithic, or paleo, diet – aka the stone age, hunter-gatherer or caveman diet – is based on the idea that if we eat like our ancient ancestors, we’ll be healthier and reduce our risk of certain diseases. But is it really a good idea to eat like cave people?

Supporters suggest modern food isn’t suitable for the human metabolism, blaming farming and agriculture for contributing to modern-day issues such as obesity. But experts question the nutritional suitability and historical accuracy of the diet. So if you’re considering changing your diet for weight-loss or health reasons, could a paleo plan be right for you?

What can you eat on a paleo diet?

The paleo diet requires you to eat foods that existed before the farming and agricultural revolution (around 10,000 years ago). On the menu is food that could be hunted, fished or gathered – so meat, fish, shellfish, poultry, eggs, veggies, roots, fruits and berries. Off the menu are grains, legumes (beans, lentils and peas), dairy, sugar and salt.

Yet paleo appears to mean different things to different people. Some followers won’t touch processed foods. But others make ‘paleo’ cakes using processed maple syrup and coconut sugar, arguing that maple and coconut trees existed before farming and agriculture, unlike sugar cane or beets, which table sugar is usually made from.

“Nutritionally speaking, sugar is sugar, no matter whether it has come from a maple tree, a coconut, sugar cane or beets”, says dietitian Sophie Medlin. “You may be able to get a marginal amount of electrolytes (salts needed for normal cell and organ function) from some sugars, but that’s like putting a gherkin on a burger and calling it healthy”, she adds.

Is a paleo diet healthy?

Whole foods are encouraged on the paleo diet, which is of course healthy advice. But could cutting out all foods developed since the paleolithic era lead to a risk of nutritional deficiencies?

“Eliminating dairy could increase the risk of calcium deficiency, and avoiding many starchy foods, as this diet does, can reduce the amount of fibre you eat. This could be a problem for your gut microbiome, which thrives off digesting fibre”, says Medlin.

Other sources of calcium include dark leafy greens and fish such as sardines (especially the bones), while fibre is found in vegetables and fruits.

Of course, in cutting out modern foods, you’re eliminating the majority of processed foods, from minimally to ultra-processed, from your diet. When avoiding processed vegetarian protein sources, such as tofu, oats, seitan or tempeh, it’s important to ensure you’re not replacing them with too much red meat. The NHS advises you to eat no more than 70g of red (and processed) meat per day.

One of the issues is that fatty cuts of meat may be high in saturated fats. “We need some fat in our diet to help absorb vitamins, but too much fat, especially saturated fats, can raise your cholesterol, increasing the risk of heart disease”, advises Medlin. According to the NHS, men should eat no more than 30g of saturated fat per day and women 20g. There is also a link between red (and processed) meat and bowel cancer. You can eat meat, fish and eggs on the paleo diet.

Avoiding or limiting salt, as recommended by a paleo diet, can reduce the risks of raised blood pressure, thereby cutting the risk of heart disease and stroke.

So there are benefits of the paleo diet, but “there is no clear scientific evidence for claims that (it) helps prevent or treat medical conditions. In fact, much research is in favour of eating wholegrains and legumes for health issues, such as reducing the risk of cardiovascular disease”, says Medlin.

Is a paleo diet good for weight loss?

There are no weight-loss guarantees on a paleo diet, though some small studies show it can be effective for short-term weight reduction. If you eliminate a food source and don’t replace it with the same number of calories, you may of course lose weight. On the other hand, if you replace legumes, grains and dairy with higher-calorie sources, you may gain weight.

“A paleo diet may help you to lose weight, but on the whole it is not well balanced”, says Medlin. “Diets to promote weight loss can still include pulses, dairy and some wholegrains.” Medlin adds that the best weight-loss diet is one you can stick to, so if you are overweight and the paleo diet works for you, it could be worth a try. But be aware that research suggests it isn’t easy to follow.

A study in the American Journal of Clinical Nutrition followed 250 overweight people for a year as they dieted with minimal professional support, allowing them to opt into a Mediterranean food plan, intermittent fasting, or a ‘paleo’ plan including some dairy, legumes and grains (making it much easier than a traditional paleo diet). After one year, the ‘paleo’ plan had the lowest retention rate, with just over a third sticking to it.

What was a real paleolithic diet?

The paleolithic era stretches from about 2.5 million to 10,000 years ago. Much of what we know about the period is based on studies of skeletal remains, human artefacts and modern hunter-gatherers.

“There’s not much information”, says Mark Thomas, Professor of Genetics at University College London. “It’s reasonable to say the human metabolism could be best suited to the types of diet humans have eaten for the longest period of time. The trouble with that is we don’t know a great deal about ancestral diets, and paleolithic diets were likely to be extremely variable across different regions and time periods.”

Research indicates there have been evolutionary changes since the paleolithic era, which could counter the pro-paleo argument that humans are better suited to an ancient diet. One example is the development of a gene that aids the digestion of lactose, the sugar found in milk. “This gene has evolved over the last six to eight thousand years, in areas where humans started dairy farming. It is found in Europeans, and in many Middle Eastern, African and southern Asian populations”, says Professor Thomas. However, this gene is not as prevelant in areas where dairy farming was, and is still not, common place, such as East Asia, suggesting its evolution is directly influenced by the introduction of dairy.

The bottom line

No-one really knows what a real paleolithic diet was, but the generally accepted modern-day ‘paleo’ plan doesn’t stray too far from a balanced healthy diet. While eating the ‘paleo way’ could help you lose weight, there are always health risks when eliminating entire food groups from your diet. Experts explain you can achieve weight-loss results and be healthy with a balanced diet that includes modern grains and pulses, both of which research finds can reduce the risk of issues such as cardiovascular disease.