Aiding digestion, the immune system and overall health, the gut is one of the most hardworking organs in the human body – but it also happens to be the one we damage most regularly. Maintaining a healthy gut starts with what you put into your body, so we asked a registered nutritionist to reveal the foods we should avoid when trying to boost gut health.
Click or scroll through our gallery as we explore the foods that damage your gut health – counting down to the biggest offender of all.
While these veggies aren’t unhealthy per se, they provide little nourishment for the gut microbiome as they’re made up mostly of water, explains registered nutritionist Jen Walpole. Lettuce, cucumber and courgette offer minimal fibre, polyphenols (natural compounds that act as antioxidants) or prebiotics. “Instead, swap in leafy greens such as rocket, watercress and spinach,” says Walpole.
If you’re someone who struggles with a sensitive stomach, you might want to think about what ingredients you’re pairing these green-hued veggies with; this could be as simple as switching a dairy dressing to an olive oil–based one, or incorporating more nutrient-dense foods into your salads. “If you use cucumber and courgette, keep the skin on, as this is what holds most of the nutrients,” recommends Walpole.
Rich with caramelly flavour, dates are a popular snack and are often used in baking. However, they should be eaten in moderation, explains Walpole. While the dried fruit is loaded with fibre, it’s high in natural sugars – and excessive sugar intake, even from natural sources, can drive dysbiosis (a shift in the composition of the gut microbiome).
Due to their high sugar content, some experts recommend limiting your intake to no more than six per day, or you could swap in other alternatives. “Instead, go for whole fresh fruit for sweetness rather than dried fruit,” says Walpole. “You can use bananas in recipes to add natural sweetness, rather than dates.”
While it might seem healthier, this creamy condiment could be doing your gut more harm than you realise. “Low-fat versions of mayonnaise often replace fat with starches, gums and sugar, all feeding opportunistic microbes and increasing inflammation,” says Walpole. “These products often include starch and glucose syrup, both associated with gut barrier disruption.”
If you’re a lover of mayonnaise, Walpole suggests opting for a full-fat mayo instead or, better still, one made with 100% avocado oil and no seed oils. You could also try making your own at home by combining an egg yolk with fresh lemon juice or apple cider vinegar, Dijon mustard, salt and pepper and a healthy oil like extra virgin olive oil or avocado oil. This allows for better control over ingredients and what you’re putting into your body.
There has been a real surge in popularity surrounding vegan alternatives to dairy in recent years, but these options aren’t necessarily as healthy as they seem. “Vegan cheese is often ultra-processed with emulsifiers, starches and coconut or seed oils, which lack probiotic value and can irritate the gut,” says Walpole.
That’s not to say all vegan cheeses should be avoided. “Instead, go for vegan cheeses made from nuts and minimal ingredients – there are some great ones on the market now,” says Walpole. Similarly, you could try sprinkling nutritional yeast, a heat-treated, deactivated yeast, over your dishes; it’s packed with essential B vitamins and has a distinct cheesy flavour.
While they can be handy when time is tight, instant noodles hold little to no nutritional benefits and are worth avoiding if you’re trying to promote gut health. “They contain MSG, artificial flavourings and refined wheat, resulting in a low fibre, high glycaemic loaded product with zero microbiome support,” says Walpole.
Scientific research in the US has also found that consuming instant noodles on a regular basis can increase your risk of heart disease, diabetes and strokes. Swap these ultra-processed packets for wholewheat fresh or dried noodles – more often than not, they take the same time to cook.
If you’re someone who struggles with gas, bloating and constipation, it could be down to what you’re drinking. Whether it’s a full-fat soda or a diet alternative, fizzy drinks are known to be a big cause of bloating, which has also been found to lead to heartburn. These addictive beverages are also loaded with sugars, sweeteners, food dyes and additives, all of which play a role in damaging the gut.
Experts recommend limiting your consumption as much as possible or, better still, removing them from your diet altogether, especially if you struggle with irritable bowel syndrome (IBS). Switch these out for water (add in fruit and herbs to make it more exciting) and herbal teas.
Whether you prefer a vegetable-based option or a brothy style, soups can be a great way to get nutrients into your diet, but opting for a dehydrated product isn’t the way to go. “They are loaded with additives, salt, thickeners (such as maltodextrin) and preservatives, which can disrupt gut flora,” says Walpole. “Maltodextrin has been shown to suppress intestinal antimicrobial defence, too.”
While these packet alternatives have been designed to save you time, you’ll be seriously sacrificing your gut health. Instead, Walpole recommends choosing a good quality tinned or fresh soup that’s brimming with vegetables and nutrients. Alternatively, making your own from scratch is even better; make it in bulk and store in portions in the freezer for a later date.
Processed meats, such as hot dogs, ham, deli slices and tinned meats, have been categorised as carcinogens by The International Agency for Research on Cancer, and intake of such foods should be kept to a minimum. It might come as little surprise that these processed meats have also been found to disrupt the digestive system and decrease vital gut bacteria.
High in salt and additives, processed meats can increase the risk of other health problems, such as high blood pressure and bowel cancer. Experts suggest replacing them with unrefined, lean proteins such as chicken, turkey and fish, as well as plant-based options including gut-friendly tofu and tempeh.
If you’re looking to get more protein into your diet, pre-packaged bars aren’t always the best choice. “These contain artificial sweeteners, low-quality protein isolates and poorly tolerated fibres, such as inulin and chicory root,” explains Walpole. “Polyols and inulin are known to cause bloating and microbial imbalance,” she adds.
Read the labels, and you might be surprised at how much added sugar is included in each serving, too. Try opting for a handful of nuts or a serving of Greek yogurt and a piece of fruit, suggests Walpole. You could also add some clean protein powder to milk for a nutritious, protein-packed alternative.
A refreshing treat on a warm summer’s day, store-bought ice cream is often high in calories and loaded with sugar. Walpole recommends avoiding the brands that use glucose syrups, as these spike blood sugar and can harm gut barrier integrity. “Studies show us that high-sugar diets reduce beneficial gut bacteria, too,” she adds.
If you’re itching to satisfy your sweet tooth, check the labels before purchasing – look for brands that use minimal ingredients or, better yet, have a go at making a tasty alternative at home. “Try frozen full-fat yogurt or make your own ‘nice cream’ by blending frozen fruit with a little yogurt or milk,” suggests Walpole.
Love a rare rib-eye steak? Partial to a cheeseburger? You might want to rethink your dinner choice if you’re trying to boost your gut health. A research study conducted in 2019 found that red meat can disrupt the digestive system; it was seen to increase levels of trimethylamine N-oxide (TMAO), a compound made when vital gut bacteria try to break down certain foods like red meat. Too much trimethylamine can put you at risk of certain health problems, such as strokes.
Red meat does, of course, have some nutritional benefits, such as high levels of protein and certain vitamins, like iron and B12, but it also contains a lot of saturated fat and experts recommend consuming it in moderation. Switch to other protein sources like white meat, fish, beans and pulses.
Made using live culture grains and fresh milk, this fermented drink has been consumed for centuries and is known for its gut health–boosting qualities. It’s become increasingly trendy in recent years, with sweetened fruit styles now available to mask the fizzy, sour taste – but it’s worth being mindful when choosing which kefir to buy.
“Some contain more sugar than fizzy drinks,” says Walpole. She adds that while they may be marketed as a probiotic, the sugar content can negate benefits and feed dysbiosis (an imbalance of microbial species). Instead, go for plain kefir, which you can sweeten by blending with fresh fruit, if you wish.
While we’ve been led to believe that all yogurts are good for us, fruity styles can often be far from it; many have minimal live cultures and are loaded with sugar and sweeteners, as well as thickening agents. “Some contain up to five teaspoons of sugar per serving,” reveals Walpole.
Unfortunately, these fruit-flavoured yogurts are often aimed at children, too. “It’s essentially a dessert disguised as health food,” says Walpole. Skip these altogether and instead buy full-fat Greek yogurt and add in your own fresh fruit and toppings like chopped nuts and homemade fruit compote to make it more fun for children (and big kids).
Crisp, golden fried foods can be delicious, but experts recommend limiting your intake to the occasional treat. Fried foods are often cooked in cheap oils that can majorly disrupt your gut microbiome and these trans fats can be difficult for your body to digest. Consuming these high-calorie foods regularly can increase your risk of certain health problems, too, including heart disease and high cholesterol.
Keep fried foods to a minimum, and swap to healthier alternatives like stir-frying or air-frying breaded or battered foods instead; homemade chicken nuggets or fish fingers are easy to make and can still achieve that crispy coating when cooked in an air fryer or oven. What’s more, your gut will seriously thank you.
Can’t get enough of this decadent toast topper? You might want to rethink your options. Described by Walpole as a "gut-damaging cocktail", processed versions of chocolate spread are high in sugar and contain palm oil and emulsifiers. “Emulsifiers like soy lecithin and polysorbates may also impair the mucosal barrier,” she adds. This protective layer, which stops the body from coming into contact with contents from the gut, is vital for normal body function.
Combining this spread with white bread is a bad recipe for your gut, too, as white bread can also play havoc with your digestive system. Instead of opting for the store-bought varieties, try making your own at home by blending hazelnuts with raw cacao powder for a minimal effort sandwich spread the kids will still love.
You might think they appear to be the better alternative to traditional full-fat ice cream, but low-calorie options and sugar-free syrups are usually far worse for your body. “These are often sweetened with polyols that ferment in the colon and cause symptoms like bloating, diarrhoea and microbiota shifts,” says Walpole.
“We know that excessive amounts of polyols are poorly absorbed and contribute to gut discomfort and dysbiosis,” adds Walpole. Add to the fact that these ‘healthier’ alternatives are often more expensive than standard ice cream, and you would be better off just going for the traditional ice cream versus this option, confirms Walpole.
Many nutritionists – including Walpole – say it’s better to go for full-fat butter than margarine. Full-fat butter is packed with essential amino acids and beneficial fats, including butyrate, which promotes gut health and contains anti-inflammatory properties. Margarine and low-fat spreads, on the other hand, aren’t as kind to the gut.
“These spreads often contain hydrogenated oils and artificial additives and lack the beneficial fatty acids of real butter,” Walpole explains. “What’s more, trans fats and industrial oils are linked to microbiome disruption.” Stick to full-fat butter next time you’ve got a craving for buttery toast for breakfast; it works better for homemade bakes and cakes, too.
It may be convenient and readily available, but white bread really isn’t worth eating if you struggle with your gut. It’s highly refined, low in fibre and rapidly digested, meaning it’ll spike your blood sugar, which can increase the risk of a number of chronic health conditions and also starve your microbiome.
Research has also shown that frequent consumption of white bread can be harmful to our overall health, too, increasing the risk of some cancers. Thankfully, there are many healthier – and more delicious – options on the market these days. “Go for wholegrain or wholemeal – or, better still, a seeded sourdough,” says Walpole.
Starting your day with a bowl of colourful, sugary cereal isn’t ideal – especially if you’re looking to boost your gut health. “These have a high glycaemic index and are low in fibre,” says Walpole. What this means is that they’ll raise your blood sugar levels considerably, and you’ll likely find yourself feeling hungry again shortly after eating.
These products are also loaded with sugars, sweeteners, food dyes and preservatives, all of which have contributing factors for disrupting the gut lining. Instead, seek out options that are labelled as being low in sugar, or have a go at making your own granola or muesli with added nuts and fruits.
The vegan food market has transformed in recent years, with everything from plant-based bacon to veggie sticky ‘ribs’ available – but this doesn't mean that they are always the healthiest options available. “Meat substitutes are considered ultra-processed and are packed with emulsifiers, soy protein isolates and artificial flavours,” says Walpole. “Many of these products contain gut-disrupting additives, too.”
It's important to note that this doesn’t mean all faux meat products are bad for you, and there are some great options out there that can improve gut health. Walpole recommends opting for soy mince that’s 100% soy with no additives. Alternatively, try tempeh, a plant-based protein that’s rich with cholesterol-lowering and gut-boosting properties.
Crunchy, salty and satisfying, it’s no secret that crisps aren’t the healthiest of snacks, so it probably comes as little surprise that they can cause havoc in your gut. Crisps, even those that claim to be healthier, often contain seed oils and additives, plus they are low in fibre and can promote oxidative stress to the gut lining.
Check the labels, and you’ll likely find you don’t recognise half of the ingredients listed, from flavour enhancers to food colourings – all of which aren't part of a healthy diet. Can’t sacrifice your savoury crunchy snacks? Try making your own at home by air-frying thinly sliced potatoes drizzled with a touch of oil and sprinkling of salt and spices. Walpole also recommends switching to salted nuts, as these contain more fibre and healthier fats.
Highly processed and containing no nutritional benefits, sweets are among the worst foods for your gut. “They are pure sugar and contain artificial colours and corn syrup,” says Walpole. “This may feed Candida infections in the gut. Studies have found that food dyes are linked to inflammation and microbiome shifts, too.”
Consuming too many sweetened foods can have devastating effects on your health, increasing your risk of heart disease, diabetes and some cancers. Too much sugar can also play a role in your mood and skin. Choose fresh fruits over sweets, says Walpole, and your gut will thank you.
While there’s arguably nothing more delicious than a roast dinner, hearty pie or plate of poutine swimming in gravy, it’s better to make your own from scratch, rather than reaching for a store-bought variety. Gravy granules are ultra-processed, packed out with artificial colourings, flavour enhancers, emulsifiers and preservatives – and they contain very few real ingredients.
“Maltodextrin suppresses anti-microbial defence, while emulsifiers can erode the mucous layer of the gut,” explains Walpole. “They are devoid of nutrition and are highly disruptive,” she adds. Use the juices from a slow-roasted joint of meat, or switch to bone or vegetable broth as the base for your gravy instead.