Should I go on the paleo diet?

Could eating like our ancestors from thousands of years ago be the key to long life? That’s what followers of the paleo diet believe… but does the evidence back it up? Here, James takes a deeper dive to help you decide if you should go paleo

If you’ve not heard of the paleo diet and you’re interested in nutrition, you may well have been living in a cave, for about, oh, 10,000 years. Which would be just as well if you do decide to choose the paleo route after reading this article.

To explain, advocates of the paleo diet eat foods similar to that might have been eaten during the Paleolithic era, which dates from approximately 2.5 million to 10,000 years ago. The diet typically includes lean meats, fish, fruit, vegetables, nuts and seeds — foods that in the past could be obtained by hunting and gathering – but not farming.

As such, a paleo diet limits foods that became common when farming emerged about 10,000 years ago. So dairy products, legumes and grains are pretty much out.

The theory behind it is that we developed over millennia to eat in a certain way, and then in the blink of an eye (from an evolutionary point of view at least) changed our diets quite radically and so we now have a genetic mismatch with the modern diet that emerged with farming. In short, our bodies are not built to eat foods that became established when farming took hold. The mismatch, advocates claim, is a factor in the prevalence of many common conditions such as diabetes, obesity and heart disease.

As ever, we are educational, not evangelical at Elevated. The diet certainly has some merits – particularly in the way that strict adherence would mean no chemicals or additives to our foods (although when you see pressed paleo bars in packages and paleo cereals in boxes, you may begin to wonder if there’s not been a thoroughly modern commercial hijacking of the movement).

Below, I take a look at some of the research into the paleo diet, if you read it and decide it’s for you, here are the paleo dos and don’ts.

What to eat

• Fruits
• Vegetables
• Nuts and seeds
• Lean meats, especially grass-fed animals or wild game
• Fish, especially those rich in omega-3 fatty acids, such as salmon, mackerel and albacore tuna
• Oils from fruits and nuts, such as olive oil or walnut oil

What to avoid

• Grains, such as wheat, oats and barley
• Legumes, such as beans, lentils, peanuts and peas
• Dairy products
• Refined sugar
• Salt
• Potatoes
• Highly processed foods in general

The paleo diet and weight loss

The most robust form of scientific evidence is a systematic review which draws together the conclusions of many other scientific studies and tries to draw a unified conclusion from them. One such study looked at 11 trials for a research paper published in Nutrition Journal in 2019 (1). It found that paleo adherents across the trials lost an average of 3.5kg on the diet. However, many trials often take place under controlled circumstances and with strong clinical support from the research team.

As such, questions persist over whether trial results can be reflected in a real-world situation. In 2020, the American Journal of Clinical Nutrition (2) published a study into weight loss using intermittent fasting and the paleo diet over a 12-month period out of clinical conditions. It found that although paleo participants lost around 1.8kg over the course of the year, just 35 per cent of those who started the diet were still following it 12 months later, indicating that people potentially have trouble sticking with the diet long term.

The paleo diet and pregnancy

The paleo diet may have positive effects for women during pregnancy according to a study in the European Journal of Obstetrics and Gynecology and Reproductive Biology (3). It looked at the pregnancies of 37 women on a paleo diet compared to 39 on a regular western diet. It found that the diet may have a positive effect on glucose tolerance, iron stores and haemoglobin levels of participants.

The paleo diet and breast cancer

A small trial study published in Medical Oncology (4) assessed the effect of the paleo diet on the weight of breast cancer patients who were undergoing radiotherapy. The results were cautiously positive. Study participants lost fat mass but retained muscle mass, and their vitamin D levels increased. The dietary intervention however was alongside a programme of daily 30-minutes of exercise, and with just 13 participants and only 11 completing the trial, the evidence is weak if encouraging.

The paleo diet and blood pressure

One systematic review published in the American Journal of Clinical Nutrition in 2020 (5) looked at the results of 50 other systematic reviews that assessed the effect of various popular diets on blood pressure. It concluded that: “evidence for the efficacy of blood pressure lowering using the Mediterranean, vegetarian, Paleolithic, low-carbohydrate, low glycaemic index, high-protein, and low-fat diets was inconsistent.”

And finally….

If after reading the above, you’ve gone potty for paleo, here’s some food for thought. One of the biggest issues with any strict diet plan is long-term compliance – how long people actually stick with it. A December 2020 trial (6) looked at internet search habits of new January dieters and created an algorithm to extrapolate how long they hung in there on their new-found diet plan. The winner was the paleo diet, but the average time was just under six weeks – some way short of 10 or so millennia that you might expect.

References

1. De Menezes EVA, Sampaio HADC, Carioca AAF, et al. Influence of Paleolithic diet on anthropometric markers in chronic diseases: Systematic review and meta-analysis [Internet]. Vol. 18, Nutrition Journal. BioMed Central Ltd.; 2019 [cited 2021 May 31]. Available from: https://pubmed.ncbi.nlm.nih.gov/31337389/
2. Jospe MR, Roy M, Brown RC, et al. Intermittent fasting, Paleolithic, or Mediterranean diets in the real world: Exploratory secondary analyses of a weight-loss trial that included choice of diet and exercise. Am J Clin Nutr [Internet]. 2020 Mar 1 [cited 2021 May 31];111(3):503–14. Available from: https://pubmed.ncbi.nlm.nih.gov/31879752/
3. Lavie M, Lavie I, Maslovitz S. Paleolithic diet during pregnancy—A potential beneficial effect on metabolic indices and birth weight. Eur J Obstet Gynecol Reprod Biol [Internet]. 2019 Nov 1 [cited 2021 May 31];242:7–11. Available from: https://pubmed.ncbi.nlm.nih.gov/31522093/
4. Klement RJ, Koebrunner PS, Krage K, Weigel MM, Sweeney RA. Short-term effects of a Paleolithic lifestyle intervention in breast cancer patients undergoing radiotherapy: a pilot and feasibility study. Med Oncol [Internet]. 2021 Jan 1 [cited 2021 May 31];38(1). Available from: https://pubmed.ncbi.nlm.nih.gov/33247817/
5. Sukhato K, Akksilp K, Dellow A, Vathesatogkit P, Anothaisintawee T. Efficacy of different dietary patterns on lowering of blood pressure level: An umbrella review. Am J Clin Nutr [Internet]. 2020 Dec 1 [cited 2021 May 31];112(6):1584–98. Available from: https://pubmed.ncbi.nlm.nih.gov/33022695/
6. Towers S, Cole S, Iboi E, et al. How long do people stick to a diet resolution? A digital epidemiological estimation of weight loss diet persistence. Public Health Nutr [Internet]. 2020 Dec 1 [cited 2021 May 31];23(18):3257–68. Available from: https://pubmed.ncbi.nlm.nih.gov/33308350/