When we talk about health, we often think about the heart, the brain, or even body weight. But one of the most important organs for overall wellbeing is the gut. Not only is it central to digestion, but it also plays a vital role in our immune system, our mood, and even how our body regulates appetite and weight.
For people who have undergone bariatric surgery, or those taking GLP-1 medications (such as Wegovy or Ozempic), looking after gut health becomes even more crucial. Both surgery and medication directly affect how food moves through the digestive tract, how nutrients are absorbed, and how the body responds to hunger and fullness cues.
So, how can you support your gut to work at its best? Let’s start with why gut health matters.
Gut health and digestion
The gut is responsible for breaking down food, absorbing nutrients, and removing waste. After bariatric surgery, the size and function of the stomach and sometimes the small intestine are changed. This means that digestion is altered, and patients need to take special care to optimise nutrient intake. GLP-1 medications also slow down stomach emptying, which can change the way food is digested and how nutrients are absorbed.
Gut health and immunity
Did you know that around 70% of the immune system sits in the gut? The gut lining and its microbiome (the trillions of bacteria and other microorganisms living there) act as the body’s first line of defence against harmful bacteria and viruses. Supporting gut health can therefore help support immunity.
Gut health and mood
The gut and brain are closely linked via the gut–brain axis. Around 90% of serotonin, often called the “happy hormone”, is produced in the gut. Research shows that gut bacteria can influence mood, anxiety, and even cognition. Many patients notice improvements in wellbeing when their digestive health is cared for.
Gut health and weight regulation
The gut helps control hunger and fullness signals through hormones such as GLP-1, PYY, and ghrelin. Bariatric surgery alters these signals, often reducing hunger and increasing satiety. GLP-1 medications mimic these effects. Keeping the gut healthy can support this natural regulation and help prevent overeating.Top tips for a healthy gut
The good news is there’s a lot we can do to look after our gut. Here are my top evidence-based tips:
1. Eat enough fibre - and build up gradually
Fibre is essential for healthy digestion, helping to keep bowel movements regular, feed beneficial gut bacteria, and support blood sugar control. After bariatric surgery, fibre intake can sometimes be low due to smaller portion sizes and dietary restrictions. Aim to gradually build up to 30g of fibre a day, in line with UK recommendations. Start slowly after surgery, as tolerance may vary, and increase fibre intake gradually to avoid discomfort such as bloating or gas.
2. Eat a variety of fibres
Not all fibre is the same, different types benefit the gut in different ways. Soluble fibre (found in oats, beans, lentils, and apples) helps with satiety and blood sugar control. Insoluble fibre (in wholegrains, nuts, seeds, and vegetables) helps keep the bowel moving. Prebiotics (in onions, garlic, leeks, asparagus, and bananas) specifically feed beneficial gut bacteria. Variety is key - try to “eat the rainbow” by choosing fruits and vegetables of different colours. Each colour contains different polyphenols, natural plant compounds that nourish beneficial gut microbes.
3. Stay well hydrated - but space fluids carefully
Adequate fluid is vital for gut health, helping fibre do its job and keeping bowel movements regular. Aim for at least 1.5 to 2 litres a day, unless advised otherwise by your healthcare team. After bariatric surgery, avoid drinking large amounts with meals as this can stretch the stomach pouch and push food through too quickly (triggering dumping syndrome). Instead, sip fluids slowly between meals.
4. Include probiotics when needed
Probiotics are “good bacteria” that can help restore balance in the gut microbiome. They may be particularly useful after a course of antibiotics, which can disrupt gut bacteria. Probiotics can be found in supplements, but also in foods such as kefir, live yoghurt, miso, kimchi, and sauerkraut (see tip 5!).
5. Try fermented foods
Fermented foods are naturally rich in beneficial bacteria and can support gut diversity. Options include kefir (fermented milk), kombucha, kimchi, sauerkraut, and live yoghurt. These foods can be a tasty, everyday way to support gut health - just introduce them gradually to avoid digestive discomfort.
6. Prioritise sleep
Good quality sleep is often overlooked, but it’s essential for a healthy gut. Poor sleep can alter the gut microbiome, increase cravings, and impact mood. Aim for 7 to 9 hours per night, keeping a consistent sleep routine where possible.
7. Keep moving
Regular physical activity supports digestion by stimulating the natural contractions of the intestines, which help move food along. Exercise has also been shown to positively influence the diversity of gut bacteria. Even gentle activities such as walking, yoga, or stretching can help.
Gut health after bariatric surgery and GLP-1s
If you’ve had bariatric surgery, or are taking a GLP-1 medication, gut health should be a particular focus. Surgery changes the anatomy of the digestive tract, while GLP-1s slow gastric emptying. Both can impact nutrient absorption and bowel function. Working with a specialist dietitian can help ensure you’re meeting your nutritional needs, minimising side effects, and protecting long-term health. Building up fibre gradually, spacing fluids, and supporting your gut microbiome through diet and lifestyle can make a real difference.
Final thoughts
The gut does far more than digest food - it plays a central role in immunity, mood, and weight regulation. Whether you’ve had bariatric surgery, are on GLP-1s, or simply want to feel your best, looking after your gut should be a top priority. By focusing on fibre, variety, hydration, probiotics, sleep, and movement, you can give your gut the care it deserves - and in turn, support your overall health.