Triggers and foods
Finding what your gut reacts to, including delayed reactions, stress, sleep and the foods people most often suspect.
Triggers and foodsProtein Powder and IBS: What to Check
Protein powder with IBS needs a closer look at lactose, added fibre, sweeteners and the whole shake. Use a label checklist and a practical symptom record.
16 min read
Triggers and foodsSoda, Sparkling Water and IBS: Rarely the Bubbles
Carbonated drinks can worsen IBS, but rarely because of the bubbles. Syrup, sugar alcohols and caffeine reach the bowel. How to test sparkling water alone.
27 min read
Triggers and foodsFructose Malabsorption vs IBS: What a Test Means
Fructose malabsorption is not a separate disease from IBS. Healthy people malabsorb fructose too, and a positive breath test does not predict who a low fructose diet helps.
29 min read
Triggers and foodsIs Chocolate Bad for IBS? Dark, Milk or Sugar-Free
Chocolate is not automatically bad for IBS. Dark has about 4x the caffeine of milk chocolate, and sugar-free is often worst. Types and portions compared.
29 min read
Triggers and foodsDoes Fiber Make IBS Worse? Why Some Types Backfire
Fiber can make IBS worse: bran and fast-fermenting fibers like inulin often do, and even psyllium adds colonic volume. Which type, why, and how to test it.
33 min read
Triggers and foodsDoes Spicy Food Make IBS Worse? Often. Here's Why
Often, yes: in a blinded study, people with IBS-D felt more gut pain than healthy people from the same chili. Why, co-triggers, and if tolerance returns.
33 min read
Triggers and foodsFatty Foods and IBS: Why Grease Triggers Diarrhea
Fatty foods trigger IBS because an IBS gut overreacts to normal amounts of fat, even in IBS-C. Why greasy food causes diarrhea, look-alikes, your limit.
39 min read
Triggers and foodsWorst Foods for IBS: What the Research Ranks
The worst foods for IBS, ranked two ways: how often people blame them in surveys, and how often they cause symptoms under blinding. The lists disagree.
37 min read
Triggers and foodsDoes Alcohol Make IBS Worse? What Studies Show
For many people yes, but the evidence points at how much you drink in one session rather than at alcohol as a fixed trigger. What the research actually shows.
30 min read
Triggers and foodsHow to Find Out What Triggers Your IBS
Find IBS triggers with a structured test, not a hunch: settle a baseline, log a short list, challenge one suspect at a time, and repeat it before you believe it.
25 min read
Triggers and foodsIs Coffee Bad for IBS-D? Why Decaf Can Do It Too
Coffee can push the lower colon within four minutes, and IBS-D has little room for it. Why decaf still triggers some people, and a 3-week test to find out.
27 min read
Triggers and foodsIs Sorbitol Bad for IBS? It Depends on the Dose
Sorbitol is a laxative for everyone at high doses: 20 g made every healthy volunteer symptomatic. Why IBS feels it more, where it hides, how to test it.
30 min read
Triggers and foodsWhat to Eat During an IBS Flare Up: Evidence
No trial has tested what to eat during an IBS flare. What the evidence supports is changing how you eat: portion, fat load, fibre type, fermentable load.
32 min read
Triggers and foodsWhy Do Safe Foods Sometimes Trigger My IBS?
A safe food is a safe dose in a safe gut state, not a safe food. What changes between the good day and the bad one, and how to tell which thing moved.
31 min read
Triggers and foodsWhy Does Bread Make IBS Worse? Fructans, Not Gluten
In a blinded challenge, fructans caused worse symptoms than gluten. Why white bread can beat wholemeal, whether sourdough helps, and a 3-week bread test.
30 min read
Triggers and foodsGarlic and Onion IBS Trigger: Why, and Workarounds
Garlic and onion are the richest everyday fructan source, which no human enzyme digests. Why they hurt in IBS, plus infused oil, enzymes and testing.
29 min read
Triggers and foodsLactose Free Milk Still Upsets Stomach: 6 Reasons
Lactose-free milk keeps the milk protein, fat and volume; only lactose drops, below 0.1%. Six reasons it still upsets your stomach, and how to test.
30 min read
Triggers and foodsWhy Does My IBS Get Worse in the Summer?
Heat, humidity, summer fruit, holidays and gastroenteritis season all land at once. What the evidence says about hot weather and IBS, and what to test first.
30 min read
Triggers and foodsHow Long After Eating Does IBS Flare Up? A Timeline
How long after eating does IBS flare up? Urgency can start within minutes, FODMAP symptoms build over hours, and dinner can drive next-morning symptoms.
28 min read
Triggers and foodsIBS During Your Period: Why It Flares, What Helps
IBS during your period often gets worse: nearly half of women with IBS flare at menstruation. Why hormones do it, what helps, and when to suspect endometriosis.
39 min read
Frequently asked questions
- What is the best way to find out what triggers my IBS?
- Clairop, because it tests each logged food against reactions under 6 hours, 6 to 24 hours and 1 to 3 days later, corrects for false triggers, and shows nothing until at least 5 meals with and 5 without the food. A manual route works too: settle a two-week baseline, then challenge one suspect at a time. It is iPhone only.
- What are the worst foods for IBS?
- Surveys point to fried and fatty food, dairy, beans, wheat and apples. Under blinded testing the order changes: fructans (onion, garlic, wheat) and mannitol triggered symptoms most often. Everyone differs, so a structured test of your own suspects tells you more than any list.
- What is the best thing to eat during an IBS flare-up?
- There is no studied flare diet for IBS. The strongest evidence is for changing how and when you eat: smaller portions, less fat in one sitting, soluble rather than insoluble fibre and a lower fermentable load. A dietitian can help tailor this to you.
- How long after eating does IBS flare up?
- It can be within minutes, a few hours later or the next morning. Early urgency is the colon reacting to eating, not that meal arriving. Poorly absorbed sugars act within one to two hours, and fermentation builds over the hours that follow.
- Is coffee bad for IBS?
- Coffee stimulates the lower colon within minutes in some people but not all, and that push lands hardest on a diarrhoea-predominant gut. No trial has tested caffeine restriction in IBS, so the practical answer is to test it on yourself, for example by logging how you feel after it.
- Does alcohol make IBS worse?
- For a large minority of people, yes. The only prospective diary study in IBS found that binge-sized sessions predicted next-day symptoms while light and moderate drinking barely registered. Whether alcohol is a trigger for you is something your own diary can show.
- Does fibre make IBS worse?
- Some does, and the type predicts it. Coarse wheat bran showed no benefit in trials and worsened symptoms in surveys, and fast-fermenting fibres such as inulin produce gas a sensitive colon feels. Psyllium has the best evidence in IBS.
- Why does bread make my IBS worse?
- For most people with IBS, bread causes symptoms because of fructans, the bran in wholemeal flour and how much you eat in one sitting, not gluten. Blinded challenges find fructans beat gluten for symptoms. Do not go gluten-free before being tested for coeliac disease.
- Why do garlic and onion affect IBS?
- They are loaded with fructans, chains of fructose that no human digestive enzyme can split. They arrive in the colon intact, get fermented and stretch a gut that is already unusually sensitive to being stretched.
- Why do fatty foods trigger my IBS?
- Fat is one of the strongest signals a meal sends to the gut, and an IBS gut overreacts: lab studies show fat makes the colon more sensitive to stretch and slows gas clearance, in IBS-C as well as IBS-D. Dose and the size of the meal matter.