Feeling bloated, tired or foggy after meals and not sure why? A simple chart can turn a jumble of "off" days into a clear picture. This guide gives you a food intolerance symptoms chart you can use straight away: the common signs, when they tend to show up, the foods and ingredients most often involved, and a printable tracker to fill in over the next two weeks.
When you're ready to look at the bigger picture, our food sensitivity test checks up to 1,600 food and non-food items from a small hair sample, with results in 5–7 working days once your sample is received.
The food intolerance symptoms chart
The most common symptoms of a food intolerance are diarrhoea, bloating, farting (wind) and tummy pain. Others include headache, feeling tired or exhausted, feeling sick, constipation, joint pain and rashes. Symptoms usually start a few hours after eating and can last for a few hours or days.
| Symptom | When it usually starts | What to note in your chart | Read more |
|---|---|---|---|
| Bloating | A few hours after eating | Time it started, how long it lasted, what you ate in the hours before | Bloating |
| Wind (farting) | A few hours after eating | Which meals, and whether it follows the same foods | Symptoms |
| Tummy pain or cramps | A few hours after eating | Where it hurts, how strong (0–10), how long | Symptoms |
| Diarrhoea or constipation | A few hours after eating | Changes from your usual pattern, and which days | Symptoms |
| Feeling sick | A few hours after eating | Whether it follows rich, fatty or particular foods or drinks | Symptoms |
| Headache | A few hours after eating | Drinks as well as food: coffee, tea, wine | Drinks |
| Tiredness or brain fog | A few hours after eating | Sleep the night before, so you can tell the two apart | Brain fog |
| Joint pain | A few hours after eating | Which days, and anything else that changed that week | Symptoms |
| Skin rashes | A few hours after eating | Where, what it looks like, a dated photo | Symptoms |
A chart works best when it shows patterns over time. One bad evening tells you very little. The same symptom after the same kind of meal, again and again, is worth noticing.
Common trigger foods and ingredients: the chart
Lactose intolerance is generally described as the most common food intolerance, and you can be intolerant to almost any food or ingredient. These are common examples, with where you'll find them.
| Ingredient | Where it's found | Explore more |
|---|---|---|
| Lactose | Milk and dairy products such as cheese and yoghurt | Problem foods |
| Gluten (wheat, rye, barley) | Bread, pasta and many baked goods | Gluten and wheat |
| Histamine | Foods and drinks like wine and cheese | Problem foods |
| Caffeine | Coffee, tea and some fizzy drinks | Drinks |
| Alcohol | Beer, wine, spirits | Drinks |
| Sulphites | Cider, beer and wine | Drinks |
| Salicylates | Some fruits, vegetables, herbs and spices | Problem foods |
| MSG (monosodium glutamate) | Ripened fruits, cured meats and savoury foods | Problem foods |
| Benzoates | A preservative in soft drinks, fruit juices, salad dressings, jams, jellies and pickles | Problem foods |
Yeast is another ingredient many people ask about. Our yeast page covers the foods it turns up in.
Your 14-day symptoms tracker (copy this)
Copy this table into a notebook, a spreadsheet or the notes app on your phone. Fill in one row per meal or snack, including drinks.
| Date and time | What I ate and drank | Symptoms (what, when, how long, 0–10) | Sleep and stress | Notes and questions |
|---|---|---|---|---|
| Mon 12:30 | Cheese sandwich, latte | Bloated 15:00, about 2 hours, 4/10 | 6 hours' sleep, busy day | Check the bread brand |
| Mon 19:00 | Pasta, tomato sauce, glass of wine | Nothing noticed | – | – |
A few tips that make the chart far more useful:
- Write it down at the time. Memories of "Tuesday lunch" fade fast.
- Include the small things. Milk in tea, a biscuit or cookie, a sauce, a handful of something while cooking.
- Log the good days too. Days without symptoms help you compare.
- Keep observations and guesses apart. "Bloated after lunch" is an observation; "the bread did it" is a guess to check later.
Want a ready-made version? Our free food and symptom diary template does the formatting for you.
Reading your chart after two weeks
Look back over your tracker and ask:
- Which symptoms come up most often? Circle the top two or three.
- When do they appear? Same time of day, same type of meal, same drinks?
- What else was going on? Poor sleep, stress, travel and illness can all play a part.
- What questions do you have now? Write them down; they are the best starting point for a chat with your doctor or a dietitian.
Don't cut foods out of your or your child's diet without advice from a doctor or dietitian, because you could miss out on important vitamins and minerals. A chart is a tool for spotting patterns, not a reason to cut out lots of foods at once.
Taking it further with an at-home hair sensitivity test
Your chart shows what happens day to day. Our At-home Hair Sensitivity Test adds a much broader view, so you can discover potential food and environmental sensitivities across hundreds of items you might never think to track.
- Individual Sensitivity Test: 600 items
- Ultimate Individual Test: 1,000 items
- Optimum Sensitivity Test: 1,600 items
Choose digital hair-sample instructions by email, or a posted collection kit (UK only). Your sample is processed by our experienced testing team, and you receive personalised results showing potential sensitivity patterns. Results in 5–7 working days once your sample is received; postal time is separate. Every test comes with a 30-day money-back guarantee on hair sensitivity tests.
Use your report alongside your chart: the report suggests items to explore, and your chart shows what actually happens when you eat them. Not sure which test suits you? Compare our tests, or read what happens after you send your hair sample.
See all our hair sensitivity tests
Food intolerance symptoms: FAQs
What is the difference between a food intolerance and a food allergy?
A food intolerance means difficulty digesting certain foods or ingredients. It is not caused by the immune system, so it cannot cause a serious allergic reaction. A food allergy involves the immune system and can cause symptoms such as itchy skin, wheezing, or swelling of the lips, face and eyes. Almost 11% of adults have a true food allergy, yet 19% believe they do. Many are actually dealing with a food intolerance or sensitivity (JAMA Network Open, 2019).
When should I see a doctor?
See a doctor if you or your child have food intolerance symptoms that keep coming back. Call your local emergency number (999 in the UK, 911 in the US and Canada, 000 in Australia, 111 in New Zealand, 112 or 999 in Ireland) if lips, mouth, throat or tongue suddenly swell, or someone is struggling to breathe or swallow; these can be signs of a serious allergic reaction.
How long after eating do food intolerance symptoms start?
Usually a few hours after eating the food or ingredient, and they can last for a few hours or days. That delay is exactly why a chart with times helps.
Can a food intolerance make you tired?
Yes. Feeling tired or exhausted is among the commonly listed symptoms. Tiredness has many causes, so note your sleep in your chart to help tell them apart.
Is a hair sensitivity test an allergy test?
No. Our tests help you discover potential food and environmental sensitivities. Bioresonance looks at energetic frequencies from a hair sample to identify potential sensitivity patterns. There's more about how our tests work in the "About our tests" section below.
Why choose Test My Food Sensitivity?
We've been helping people explore their sensitivities since 2008, with over one million tests sold across our family of brands since 2008.
About our tests
Test My Food Sensitivity offers a bioresonance hair sensitivity and intolerance test. It is not an allergy test and does not diagnose allergies or any medical condition. Use your results as a starting point and a guide, and speak to your doctor if you suspect an allergy or before making significant or prolonged changes to your diet.
