The Paleo Diet and IBS

The Paleo Diet is a way of eating that is based on trying to eat like our hunter-gatherer ancestors did. The theory behind the diet is that our bodies evolved to eat what was available at the time — vegetables, fruits, and lean meats. Paleo Diet proponents purport that these hunter-gatherers were quite healthy and fit, with strong bodies and teeth, and did not suffer from the diseases of modern-day.

Salmon with papaya chutney
Nicole S. Young / E+ / Getty Images

According to Paleo Diet proponents, the addition of grains to our diets approximately 10,000 years ago brought about a whole host of health problems. It is acknowledged that grains were convenient and allowed for the benefits of settled civilization, but thought that they brought about:

  • Dental problems
  • Heart disease
  • Diabetes
  • Obesity

Allowed Foods on the Paleo Diet

  • Fruits
  • Non-starchy vegetables
  • Healthy Fats (olives, olive oil, nuts, avocados)
  • Animal foods (grass-fed beef, pastured pork, free-range chicken, fish)

Foods to Avoid on the Paleo Diet

  • Dairy products
  • Grains (including wheat, rye, barley, corn, rice)
  • Legumes (beans, lentils, peanuts, peas)
  • Refined sugar
  • Vegetable oils (including canola, corn, peanut, soybean)
  • Processed foods containing any of the above

Purported Health Benefits of the Paleo Diet

There have not been a lot of clinical studies done on the Paleo diet.

A recent Mediterranean cohort study that consisted of 18,210 participants who were followed for 12 years found an association between adherence to the Paleo diet and reduced risk of heart disease. The researchers noted that the avoidance of ultra-processed foods seems to play a key role in these health benefits.

Currently, there is still a lack of long-term, large-scale studies to support the benefits of the Paleo diet. Additionally, a recent meta-analysis and systematic review found that the Paleolithic diet did not differ from other types of healthy diets with regard to effects on blood sugar and insulin levels.

Paleo Diet Criticisms

One of the biggest criticisms of the diet is the lack of clinical research trials. In addition, some researchers question the conclusions regarding the health of our ancestors. Some dietary experts express concerns about potential nutrient deficiencies caused by the restriction of grains and legumes, as well as concerns about excessive saturated fat consumption from eating higher amounts of red meat.

The Paleo Diet and IBS

Although I have heard a lot of anecdotal tales about IBS clearing up once a person switches to a Paleo diet, I was not able to find any research on the subject. The closest I got was this sentence from ​one research report, "A diet of grain-free whole foods with carbohydrate from cellular tubers, leaves, and fruits may produce a gastrointestinal microbiota consistent with our evolutionary condition, potentially explaining the exceptional macronutrient-independent metabolic health of non-Westernized populations, and the apparent efficacy of the modern “Paleolithic” diet on satiety and metabolism." I would love to see research being conducted as to the effect, and long-term safety, of a Paleo diet on gastrointestinal symptoms and the health of the gut flora.

That being said, it is not news that typical Western high-carbohydrate diets are contributing to obesity, diabetes and heart disease, as well as having a negative impact on our microbiomes. Choosing to eat more vegetables, fruits, and lean protein, and cutting out processed foods filled with excessive sugar, refined grains, and unhealthy fats is certainly a way toward improved overall and digestive health.

If you do decide to try the Paleo Diet, please discuss the issue with your healthcare provider. You may want to start off by choosing low-FODMAP fruits and vegetables so as to not experience increased IBS symptoms as your body adjusts to this new way of eating.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Challa HJ, Uppaluri KR. Paleolithic Diet. In:StatPearls [Internet].

  2. de la O V, Zazpe I, Goni L, Santiago S, et al. A score appraising Paleolithic diet and the risk of cardiovascular disease in a Mediterranean prospective cohort. Eur J Nutr. 2022 Mar;61(2):957-971. doi:10.1007/s00394-021-02696-9

  3. Jamka M, Kulczyński B, Juruć A, Gramza-Michałowska A, Stokes CS, Walkowiak J. The Effect of the Paleolithic Diet vs. Healthy Diets on Glucose and Insulin Homeostasis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Clin Med. 2020 Jan 21;9(2):296. doi: 10.3390/jcm9020296

  4. Fenton TR, Fenton CJ. Paleo diet still lacks evidenceAm J Clin Nutr. 2016;104(3):844. doi:10.3945/ajcn.116.139006

  5. Spreadbury I. Comparison with ancestral diets suggests dense acellular carbohydrates promote an inflammatory microbiota, and may be the primary dietary cause of leptin resistance and obesityDiabetes Metab Syndr Obes. 2012;5:175–189. doi:10.2147/DMSO.S33473

Additional Reading

By Barbara Bolen, PhD
Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.