Gut Health
What to eat, what to skip, and how long it takes
Gut Health
The short answer
Gut health improves fastest when you increase the variety of plants you eat, not the quantity of any single superfood. Aim for 30 different plants a week, add one fermented food daily, and raise fibre slowly toward 30g. Most people notice a difference within two to four weeks.
I spent three years growing microgreens in London and supplying them to health shops, restaurants and colleges. In that time I had roughly the same conversation several hundred times, and it almost always started the same way. Someone would pick up a punnet of radish shoots and ask whether it would fix their bloating.
The honest answer was never yes. But the question underneath it was a good one: I feel wrong after I eat and I don't know why, and I'd quite like someone to tell me what to do about it without selling me a £60 tub of powder.
This is that answer, as briefly as I can give it.
One thing first. This is general information, not medical advice. Persistent symptoms, including blood, unexplained weight loss, pain that wakes you up, or a change in bowel habit lasting more than three weeks, need a GP rather than a blog post.
Your large intestine holds roughly a trillion bacteria across hundreds of species. They ferment the parts of plants you cannot digest yourself, and in doing so produce short-chain fatty acids that feed the cells lining your colon. Feed them well and they produce plenty. Feed them poorly and your gut lining is worse off for it.
So the useful mental model is this: you are not only feeding yourself, you are feeding them.
The American Gut Project analysed thousands of participants' microbiomes alongside their diets. The finding that stuck: people eating more than 30 different plant types a week had markedly more diverse microbiomes than people eating 10 or fewer. Not more grams of plants. More kinds.
Thirty sounds like a lot until you count properly.
Herbs count. Spices count. Nuts, seeds, grains, pulses, tea and coffee all count.A bowl of porridge with mixed seeds, cinnamon and berries carries seven before you have left the kitchen.
Introduce them in this order. Starting with fibre before your bacteria are ready is the most common way people talk themselves out of this entirely.
Live bacteria, delivered directly. Start with a tablespoon rather than a jar, because going big on day one will convince you fermented food does not agree with you.
It has to be genuinely live. Look in the chilled section, check for the word unpasteurised, and if the ingredients run past four items you are holding a pickle rather than a ferment. Both are fine to eat. Only one does this job.
This is what your bacteria actually eat, and it matters more than the probiotic side of the equation. Oats, slightly green bananas, garlic, onions, leeks, beans and lentils all qualify. The NHS recommends 30g a day. UK average intake sits nearer 20g, so most people have a 10g gap to close.
Close it by 3g to 5g a week, not overnight, and drink more water as you go.
Anti-inflammatory, and it speeds gastric emptying, which is the mechanism behind its reputation for settling nausea and that heavy feeling after a meal. Kitchen tip worth having: freeze the root and grate it from frozen. Finer grate, no peeling, and no more soft ginger forgotten in the drawer.
Fibre, polyphenols, magnesium and folate, plus a sulphur-containing sugar that appears to selectively feed beneficial bacteria. Rotate them. Four different greens across a week does more than the same one four times.
Microgreens earn their place here as a diversity multiplier: four or five plant types per punnet, and you can grow them on a windowsill in eight days.
Adding good things matters more than removing bad ones. But emulsifiers, the ingredients that stop things separating, are worth knowing about. Research on their effect on the gut mucus layer has raised legitimate concerns. Much of the strongest evidence comes from animal models and I do not want to overstate it, but the direction of travel is not reassuring. They cluster in heavily processed food, which is worth eating less of for a dozen other reasons anyway.
The first three ingredients are the product.
Everything after that is a rounding errorIngredients are listed by weight. If sugar, a syrup or a refined oil appears in the first three, that is substantially what you are eating, whatever the front of the pack says. A granola advertising gut health with sugar listed second is a dessert. It takes four seconds to check and it works on everything. More on that in how to read a food label.
The two-week dip is the whole game. Nearly everyone who tries to overhaul their gut in a weekend hits it, decides it is not working, and stops one week before it would have started working.
Most gut health advice fails at this point, because it hands you principles and leaves you to work out the shopping. So here is the actual week, in the order I would run it.
The number you wrote down on Friday is the thing to move. Not weight, not bloating, not how you feel on any given morning, all of which fluctuate for reasons that have nothing to do with your gut. Plant count is the one number you control directly and the one that tracks the outcome.
Move one number: how many different plants you ate this week.
From 10 toward 30, a few at a timeNot a protocol, not a reset, not a cleanse. One number and a fortnight of patience.
Most people notice improved digestion within two to four weeks of consistent change, though meaningful microbiome diversity shifts take three to six months. The first fortnight often feels worse before it feels better, as fibre intake rises and your bacterial population adjusts.
There isn't one, and that is the actual answer rather than a dodge. Diversity beats any individual food. People eating over 30 different plant types weekly show markedly more diverse microbiomes than those eating 10 or fewer.
Not necessarily. Feeding the bacteria you already have, with fibre and fermented food, generally does more than importing new ones. Probiotics are most useful after antibiotics, or for specific conditions where particular strains have evidence behind them.
Because you increased it too quickly. Your gut bacteria need time to scale up to handle more fermentable material. Add 3g to 5g a week rather than jumping straight to 30g, and drink more water alongside it.
It can be, if it is genuinely live and not loaded with sugar. Many commercial kombuchas are pasteurised, sweetened, or both. Check the chilled section, look for live cultures, and check sugar per 100ml. Anything above about 5g is closer to a soft drink.