The Paleo Diet: What it is and how it works

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The paleo diet has become popular because it’s seen as a natural way of eating. It is based on the diets of paleolithic humans and focuses on increasing the consumption of meat, nuts and fresh fruit and vegetables, and it limits the amount of grains and processed foods consumed. 

Many celebrities have embraced the paleo diet, further popularizing it, but there is little scientific evidence to back up the supposed health benefits. In some cases it seems to carry more risk than reward, with doctors advised to be careful with patients with osteoporosis following the paleo diet – due to the low calcium intake. Additionally, there have been connections made between red meat consumption and bowel cancer, which doesn’t ring true with one of the core paleo diet principles of eating grass-fed meat. 

So why would a modern human need to emulate an ancient diet, especially when we have access to a wider range of foods than our ancestors did? Plus, are there actually any benefits to following the paleo diet, or do you need to consider supplements like the best multivitamin for women to make up any shortfalls? Read on for everything you need to know.

What is the paleo diet?

The paleo diet is based on what humans most likely ate 2.5 million-10,000 years ago. It is a diet rich in lean meats, fish, fruits and vegetables, in line with the diet of paleolithic hunter-gatherers. A study from the International Association for the Study of Obesity indicates that the hunter-gatherer lifestyle and diet contributes to excellent cardiovascular and metabolic health. 

The lives of people in the paleolithic era are a far cry from our modern, often sedentary lifestyles, heavy with processed meals and fast food, so the romanticism of the paleo diet is clear, but are there health benefits? Does this ancient diet have any applications for modern humans?

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What can you eat on the paleo diet?

The paleo diet encourages eating plenty of lean meat, fish, fruit and vegetables, as our hunter-gatherer ancestors would have consumed. However, building meals around a protein source as recommended by the paleo diet deviates from the government dietary guidelines, as the USDA recommends basing your meals around starchy food and grains, such as oats or potatoes. 

Snacking on seeds and nuts or berries instead of processed foods like chips or sweets could increase your intake of vitamins and minerals, supporting your body to function at its best. Dr Nirusa Kumaran, medical director and founder of Elemental Health Clinic, says that one of the key principles of the paleo diet is to cut out heavily processed foods. 

“The paleo diet, also known as ‘the caveman diet,’ focuses on eating lean grass-fed meat, fish, fruit and vegetables,” she says. “This means that you should eliminate processed foods and most dairy products, and instead eat a diet rich in nuts, seeds, fruit, lean meat – such as lamb and chicken – and omega 3 containing fish, such as salmon and mackerel.”

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What can’t you eat on a paleo diet?

Kumaran explains that certain foods are restricted when following the paleo diet. “The diet typically restricts grains, legumes, sugar, salt and processed foods, including alcohol, pasta, bread, potatoes, beans and cheese,” she says. 

The paleo diet encourages you to cut out or reduce refined foods, including sugar, flour, dairy and salt. The resulting diet ends up being low in starchy foods, with wheat products (like bread and pasta) and even mostly unprocessed products, such as potatoes and legumes, all heavily restricted. Dairy is also a no-go, which makes calcium deficiency a possibility in those who follow the paleo diet. 

Have a look at the Mediterranean diet, for another healthy alternative to paleo.

What are the potential benefits of a paleo diet?

The paleo diet may have health benefits, particularly for those who are of poor health – due to issues like obesity and diabetes – as well as lowering blood pressure and maximizing high-quality protein intake. 

A study in 2000 from the American Journal of Clinical Nutrition suggests that consumption of leaner protein led to the bodies of hunter-gatherers relying more heavily on protein than carbohydrates for energy, which could potentially protect against certain diseases.

According to Kumaran: “The potential benefits of the paleo diet include weight loss, blood pressure and blood sugar control, improvement and prevention of autoimmune health conditions, and improved appetite management.” 

She adds: “Lowering the amount of processed foods that you eat means you are less likely to snack on high-calorie, high-sugar and low-nutrient foods. People following this diet could also experience more energy, as they are eliminating the high-sugar, processed foods they were used to eating.”

Research in 2015 published by the European Journal of Clinical Nutrition showed that the paleo diet can be useful in supporting those with type 2 diabetes, showing promising results in increasing insulin sensitivity. 

Kumaran also says that, overall, the paleo diet can support those with certain underlying health conditions. 

“The low sugar and low carbohydrate aspect of the diet could be beneficial for those with diabetes, heart problems, obesity and other metabolic health conditions as it can help increase insulin sensitivity,” she says. 

“If you have an autoimmune condition, you may find a paleo diet can aid you going into remission, as one likely cause of the immune activation is due to proteins (often found in grains, legumes and dairy). Once these proteins are removed, the immune process is no longer triggered, aiding disease remission. 

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Is the paleo diet safe?

An American Journal of Clinical Nutrition report from 2016 suggests that the paleo diet lacks evidence to support it as the holy grail of healthy eating, which is how it is often presented. It may be problematic for some people to follow, particularly if they already have nutrient deficiencies or underlying health problems.

Kumaran warns only to make drastic dietary changes under medical guidance. 

“I would always advise that any dietary modifications which could potentially be extreme, such as this, should be done under the guidance of a qualified health professional,” she says. “It’s important to be aware that this diet restricts food groups which have many nutrients that our body requires. For example, dairy, which is a good source of calcium, and legumes and wholegrains which our body uses for energy and is a good source of fiber. As such, the paleo diet may put you at risk of nutrient deficiencies.”

A 2019 report in Food Research International showed dietary fiber to be important for our digestion, and the paleo diet may make it difficult to achieve your daily fiber requirements by restricting starchy foods, such as grains and legumes. 

Kumaran also says that the low-fiber nature of the paleo diet could lead to health issues. “A diet lacking in fiber could risk dysbiosis, an imbalance of the gut microbiome, which could then be a precursor to the onset of a health problem in future. Additionally, lacking fiber in the diet increases your risk of constipation, and without optimal bowel function our body cannot detoxify effectively.” 

A study in Gut Microbes also indicates that our bodies struggle to function properly without adequate dietary fiber and that we need it to support our gut microbiome and successfully digest food. 

You can check out our guide to gut health and why it’s important for more about the role fiber plays in maintaining good gut health.

This article is for informational purposes only and is not meant to offer medical advice.

Lou Mudge
Health Writer

Lou Mudge is a health writer based in Bath, United Kingdom for Future PLC. She holds an undergraduate degree in creative writing from Bath Spa University, and her work has appeared in Live Science, Tom's Guide, Fit & Well, Coach, T3, and Tech Radar, among others. She regularly writes about health and fitness-related topics such as air quality, gut health, diet and nutrition and the impacts these things have on our lives. 

She has worked for the University of Bath on a chemistry research project and produced a short book in collaboration with the department of education at Bath Spa University.