How to Improve Gut Health: Diet and Lifestyle Tips

Written by Kate Hilton, RD Published 19 April 2024

Medically reviewed by Sonia Khan, Pharmacist Last reviewed 7 September 2026

The changes most consistently linked to better gut health are eating more fibre from a wide range of plants, eating fermented foods regularly, moving more, sleeping well and keeping alcohol in check. Your gut bacteria start responding to a change of diet within days, though symptoms usually take weeks of consistency to improve. This guide covers the signs of an unhealthy gut, what long-term problems it is linked to, what damages it, the specific diet and lifestyle changes the research supports, and how long each takes to work.

Why is our gut health important?

Your gut is home to trillions of bacteria, viruses and fungi, together known as the gut microbiome. These microbes help digest food, make certain vitamins, train the immune system and produce compounds that influence organs well beyond the gut, which is why the gut is sometimes called the body's second brain.

A healthy gut supports:

Digesting food and absorbing nutrients
Synthesizing important vitamins and minerals
Protecting against harmful pathogens
Supporting the immune system
Protect against many chronic diseases
Regulating metabolism
Influencing mood and behaviour
Sleep quality

Research links the make-up of the gut microbiome to immune function, mood and the risk of several long-term conditions, although much of this evidence shows association rather than cause. Our guide to the gut microbiome covers what it is and how it works in more depth.

How do I know if my gut is unhealthy?

An unhealthy gut does not only show up as digestive trouble. Because gut bacteria are involved in immunity, energy and the gut-brain axis, the signs can appear around the body. The most common signs include the following.

Digestive symptoms. Persistent bloating, gas, diarrhoea after eating, constipation or heartburn.
Food sensitivities. Digestive symptoms after foods that previously caused no problems, a pattern our guide to food intolerance covers in detail.
Getting ill more often. Much of the immune system sits in and around the gut, and poor gut health is linked to weaker immune responses.
Ongoing tiredness. Fatigue that will not shift can be linked to poor nutrient absorption or a food intolerance, though it has many other causes worth ruling out with a GP. Tiredness after eating in particular has its own common explanations.
Broken sleep. Sleep quality and gut bacteria appear to move together in research, although which affects which is not clear.
Low mood or anxiety. The gut and brain signal to each other constantly, and mood changes sometimes travel with gut symptoms. Some people notice anxiety after eating in particular.
Skin flare-ups. Conditions such as eczema, acne and rosacea are linked with the gut in some research, although cause and effect are not settled.
Weight changes you cannot explain. Weight can shift when digestion and nutrient absorption are disturbed. Unexplained weight loss always needs a GP appointment rather than a home test.

A gut microbiome test shows which bacteria are present in your gut and how diverse they are. It cannot diagnose any condition, but it gives you a baseline to compare against after you make changes.

What can poor gut health lead to?

An imbalance in gut bacteria that persists, which researchers call dysbiosis, has been linked to conditions well beyond the gut. A 2020 review of the gut microbiome in health and disease connects it to digestive, metabolic, immune and mental health conditions. Nearly all of this research shows association rather than cause. The gut bacteria of people with these conditions look different from the gut bacteria of people without them, and researchers do not yet know whether the bacteria change first or the condition develops first.

Metabolic conditions. People with obesity, type 2 diabetes and heart disease tend to carry a different mix of gut bacteria from people without them, according to a 2021 review of two decades of research.
IBS. A review of 24 studies found measurable differences in the gut bacteria of people with IBS, though it could not say whether those differences cause IBS or result from it. Our guide to the gut microbiome and IBS covers the link in more detail.
A more permeable gut lining. Ongoing damage to the gut lining can make it easier for bacteria and their by-products to cross into the bloodstream, sometimes called leaky gut.
Mental health. A 2021 King's College London analysis of 59 studies found that people with depression and anxiety tend to have fewer of the gut bacteria linked with lower inflammation. Studies of this kind cannot show which direction the effect runs, and changing your gut is not a treatment for either condition. If low mood or anxiety is affecting your life, speak to your GP. In England you can also refer yourself directly to NHS talking therapies.
Brain and nerve conditions. Early research is exploring links between gut bacteria and conditions such as Parkinson's disease and Alzheimer's disease, summarised in a 2022 review. This work is at the association stage, and it is not something to read into everyday gut symptoms.

Serious conditions develop from many causes, and gut symptoms on their own do not mean any of these lie ahead. Persistent symptoms are worth acting on for their own sake, and the same everyday changes that ease them also support long-term health.

What affects gut health?

Several everyday factors shape the balance of your gut bacteria:

Diet: diets high in sugar and heavily processed foods feed less helpful bacteria, while a lack of fibre starves the beneficial ones. What you eat is the single biggest influence on your gut microbiome that you can control.
Antibiotics and certain medicines: antibiotics cannot tell helpful bacteria from harmful ones, so a course kills both and reduces diversity. Other medicines affect the gut too, including NSAID's such as Naproxen which can damage the lining of the stomach. Researchers are also studying how widely used prescription medicines relate to gut bacteria, including statins and the gut microbiome. Never stop or change a prescribed medicine because of its possible gut effects; speak to your GP or pharmacist.
Infections and illnesses: gut infections such as gastroenteritis can damage the gut lining and disrupt the balance of bacteria, and in some people trigger longer-term problems such as IBS. gut parasites can also cause unpleasant symptoms and disturb the gut in the same way.
Stress: ongoing stress raises cortisol, which affects how quickly food moves through the gut and how much blood reaches it. Research also suggests the relationship runs both ways, with stress altering gut bacteria and gut bacteria influencing the stress response, based on a 2019 review of human studies.
Alcohol: alcohol can irritate and damage the gut lining, making it easier for bacteria and their by-products to cross into the bloodstream.
Sleep: irregular or poor-quality sleep disturbs the body's internal clock, and gut bacteria follow daily rhythms of their own.
Hydration: too little fluid makes stools harder and drier, which commonly leads to constipation.
Physical activity: regular movement keeps food moving through the intestines and is linked with a more diverse microbiome. Inactivity slows digestion.

How can I improve my gut health?

Diet and lifestyle are the two levers you control, and diet is the stronger of the two. According to PubMed-indexed research, a 2026 review of 80 controlled trials found that plant-based, high-fibre and Mediterranean-style diets consistently increased the bacteria that produce short-chain fatty acids, the compounds your gut bacteria make when they break down fibre, while Western-style diets did the opposite.

Foods to improve your gut health

Fibre-rich foods: beneficial gut bacteria ferment fibre into short-chain fatty acids, which feed the cells lining your colon. A 2018 study of 151 adults found that people who ate more fibre carried more of these beneficial bacteria. Fruits, vegetables, beans, lentils, nuts, seeds and whole grains all count.
A wide variety of plants: variety matters as much as quantity. In the American Gut project, which analysed samples from over 10,000 people in the UK, US and Australia, people who ate more than 30 different plant foods a week had more diverse gut bacteria than people who ate 10 or fewer. Different plants feed different bacteria, so mixing up your vegetables, grains, herbs and pulses does more than eating a large amount of one.
Fermented foods: yoghurt, kefir, sauerkraut and kimchi contain live cultures. In a 2021 Stanford trial where healthy adults were randomly assigned to add either fermented foods or extra fibre for ten weeks, the fermented food group saw the variety of their gut bacteria increase steadily and several markers of inflammation fall.

If you are weighing up probiotics and prebiotics, our guide explains the difference between them and what each does in the gut.

Recommended read - The best foods for gut health and how they help.

Lifestyle Changes

Regular exercise: movement does more than burn energy. A 2018 study put 32 previously sedentary adults through six weeks of endurance exercise without changing their diets. Their gut bacteria shifted towards species that produce short-chain fatty acids, and the changes faded once they stopped exercising, which suggests the gut benefits of exercise depend on keeping it up.
Adequate sleep: aim for 7 to 9 hours a night. A 2019 study that tracked people's sleep with wrist monitors found those who slept more efficiently had more diverse gut bacteria. This kind of study cannot show which direction the effect runs, but sleep and the gut clearly move together.
Stress management: keeping stress in check reduces the cortisol that interferes with normal gut function. Whatever works for you counts, whether that is exercise, time outdoors or talking to someone.
Avoid smoking: smoking harms the gut along with nearly everything else, and stopping is one of the best things you can do for your overall health. The NHS offers free support to quit.
Hydration: steady water intake through the day softens stools and helps them pass more easily.
Limit alcohol: cutting down protects the gut lining. UK guidance is no more than 14 units a week, spread over several days.
Mindful eating: eating slowly and chewing thoroughly gives digestion a head start and reduces the strain on your gut.

A gut-friendly diet and lifestyle lays the foundation for beneficial bacteria such as Bifidobacterium and Lactobacillus to flourish.

How long does it take to improve gut health?

Your gut bacteria respond faster than you might expect. A well-known 2014 study switched volunteers onto entirely plant-based or entirely animal-based diets and found the make-up of their gut bacteria changed measurably within days. Symptoms take longer. For a minor imbalance in the good and bad bacteria within the gut, people often notice a difference within a few weeks of consistent changes.

Gut dysbiosis is a more established imbalance of the bacteria within the gut, and correcting it takes longer, typically weeks to a few months of sustained changes. In the Stanford fermented food trial, the increase in bacterial diversity built gradually across the full ten weeks rather than arriving at once.

Consistency matters more than intensity. A gut-friendly week followed by a return to old habits will not hold on to the improvement.

How will I know if my gut health has improved?

The main signs of improving gut health are:

Fewer digestive symptoms: less bloating and gas, and regular, comfortable bowel movements.
Better mood and energy: many people report feeling brighter and less sluggish as digestive symptoms settle.
Better sleep: both the quality and length of restorative sleep.
Improved skin: the gut and the skin are connected via the gut-skin axis, and some people find skin inflammation eases as their gut settles.

You can also take a gut microbiome test before and after making changes to see how the composition of your gut bacteria has shifted.

What does a healthy microbiome look like?

When to see a GP

Most gut symptoms improve with the changes above, but some need a doctor rather than a diet change. See your GP if you have blood in your stool, unexplained weight loss, a change in bowel habit lasting more than three weeks, difficulty swallowing, persistent vomiting, or new ongoing gut symptoms starting over the age of 50. The same applies if you have iron-deficiency anaemia or a family history of bowel or ovarian cancer. These symptoms usually have ordinary explanations, but they are the ones the NHS asks GPs to check properly, and no test you can do at home replaces that.