Which Diet Does Science Say Is Best For Gut Health?

Written by Clare Carrick ANutr (BHSc)

Scientifically reviewed by Dr Fathalla Ali, PHD Paediatrics


Google ‘What’s the best diet for gut health?’ and you will be bombarded with foods you should avoid, supplements you should take, keto meal plans to follow, and ‘detox’ programs you should sign up for. With all of this conflicting and unfounded advice being thrown at you from all angles, you could be forgiven for assuming that looking after your gut requires a complicated and regimented approach.

Whilst diet is only one tool in the toolbox for optimising our gut health, it has a significant impact on our gut composition. Let’s take a quick peek at what the scientific evidence recommends we eat for our best shot at a healthy gut…

But First, What Is a Healthy Gut?

Every single person has their own unique gut microbiome composition, influenced by their delivery mode, their diet, medication use, lifestyle and culture, and even whether or not they own a pet (1)! The best indicator for a ‘healthy gut’ is a rich and diverse community of gut bugs (1). If things get a bit out of whack in the gut, with the more beneficial bacteria being overrun by less beneficial bacteria, you may start to experience some unpleasant symptoms (1). In the short term, these might present as gut symptoms like constipation or diarrhoea, but if this imbalance continues for a long time you will have an increased risk of developing cardiovascular disease, cancer, diabetes, obesity, and neurological disorders like Alzheimer’s disease, depression, and autism (1).

An Unhappy Western Gut

What we eat plays a crucial role in the health and composition of our gut (1). Typically, the Western diet contains high levels of saturated fats and proteins from animals, simple sugars, and salt. Unfortunately for us (and our gut bugs) this classic ‘Western diet’ does not nurture the beneficial gut bugs, can decrease the production of short chain fatty acids, and can even help to fuel the unbeneficial gut bugs (1). This can cause a gut imbalance, known as dysbiosis, and also potentially damages the barrier of the intestine, leading to intestinal permeability, or ‘leaky gut’ (1). Having an abnormally ‘leaky gut’ may affect your ability to absorb nutrients from foods, and can also allow toxic molecules to enter your blood stream (1). Gut dysbiosis can increase inflammation and your risk of developing IBD (1).

How About the Low FODMAP Diet for Gut Health?

The Low FODMAP Diet, which stands for Fermentable Oligosaccharides, Dissacharides, Monosaccharides, And Polyols, restricts the ingestion of short-chain carbohydrates and sugar alcohols, all of which have been shown to trigger gut symptoms in more sensitive tummies (2).  Whilst the low FODMAP diet is designed to help the gut, it is definitely not recommended for long term gut health, and certainly not in a population-wide capacity (1). The intended purpose of the low FODMAP diet is to reduce uncomfortable gut symptoms and help people identify potential trigger foods, but this only works for select conditions and people (1, 3). Following the low FODMAP diet for an extended period of time has actually been shown to reduce beneficial bacteria (1). This makes sense, because the diet cuts out many of the prebiotic foods that your beneficial gut bugs love to feast on (1, 3).

And The Winner Is….

The Mediterranean Diet comes out on top for its gut health benefits (1). This diet centres around high amounts of plant foods, including fruit, vegetables, nuts, seeds, legumes, and whole grains, extra virgin olive oil as its main source of fat, moderate amounts of dairy, especially fermented products, eggs, seafood, and small amounts of red wine (4). The abundance of plants in the Mediterranean Diet is key to its gut-loving reputation, alongside its inclusion of high levels of fatty fish, which can boost the production of anti-inflammatory compounds and help restore our favourite types of gut bugs (1). This way of eating has been shown to increase gut diversity, boost short-chain-fatty-acid levels, and help the beneficial bacteria to thrive (1, 4). Following a Mediterranean diet may be the key to a healthy gut, helping you to avoid gut imbalances, unpleasant gut symptoms, immune dysfunction, and potential neurological disorders (1).


  1. Rinninella E, Cintoni M, Raoul P, Lopetuso LR, Scaldaferri F, Pulcini G, Miggiano GA, Gasbarrini A, Mele MC. Food components and dietary habits: keys for a healthy gut microbiota composition. Nutrients. 2019 Oct;11(10):2393.
  2. Gibson PR. History of the low FODMAP diet. Journal of gastroenterology and hepatology. 2017 Mar;32:5-7.
  3. Altobelli E, Del Negro V, Angeletti PM, Latella G. Low-FODMAP diet improves irritable bowel syndrome symptoms: a meta-analysis. Nutrients. 2017 Sep;9(9):940.
  4. Merra G, Noce A, Marrone G, Cintoni M, Tarsitano MG, Capacci A, De Lorenzo A. Influence of mediterranean diet on human gut microbiota. Nutrients. 2021 Jan;13(1):7.

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