How to Start an Elimination Diet UK
If your food diary has pointed towards certain trigger foods, an elimination diet is the next logical step. It is a structured way to confirm which foods are causing your symptoms by removing them and then carefully reintroducing them. This guide explains how to do it safely and effectively in the UK, with reference to NHS guidance.
What Is an Elimination Diet?
An elimination diet is a short-term eating plan designed to identify foods that your body does not tolerate well. It is not a weight loss diet, a fad, or a permanent way of eating. It is a diagnostic tool — a structured experiment to help you and your healthcare provider work out which specific foods are causing your symptoms.
The principle is straightforward: remove suspected trigger foods, wait for symptoms to improve, then reintroduce foods one at a time to see which ones cause symptoms to return. The entire process typically takes 6–12 weeks.
When is an elimination diet useful?
- You have persistent digestive symptoms (bloating, cramps, diarrhoea, constipation) that your GP has not been able to attribute to a specific condition
- You suspect food intolerances but are not sure which foods are involved
- Your food diary has pointed towards possible triggers but you want to confirm them
- Your GP or dietitian has recommended an elimination approach
Speak to your GP first
The NHS recommends consulting a healthcare professional before starting any elimination diet. This is especially important if you suspect a food allergy (which requires proper testing), are pregnant or breastfeeding, have a history of disordered eating, or plan to eliminate multiple food groups.
The 3 Phases of an Elimination Diet
Every elimination diet follows the same basic structure, regardless of which specific approach you use:
Phase 1: Elimination (2–6 weeks)
Remove all suspected trigger foods from your diet completely. This means reading every label, asking about ingredients when eating out, and being meticulous about what you consume. Half-measures will not give you clear results.
During this phase, keep a detailed food and symptom diary. If your symptoms improve significantly, it suggests that one or more of the eliminated foods was contributing. If symptoms do not improve after 4–6 weeks of strict elimination, the foods you removed may not be the issue, and you should discuss next steps with your GP.
Phase 2: Reintroduction (4–8 weeks)
This is the most important phase. Reintroduce one food group at a time, eating a normal portion of it for 2–3 days while continuing to avoid all other eliminated foods. Then wait 3 days before introducing the next food, even if you had no reaction — some symptoms are delayed.
For each food you reintroduce, record:
- What you ate and how much
- Any symptoms that appeared (and their timing)
- The severity of any symptoms
- Whether symptoms resolved when you stopped eating that food again
If a food causes symptoms to return, remove it again and wait until symptoms clear before testing the next food. If a food causes no symptoms, it is likely safe to add back to your regular diet.
Phase 3: Maintenance (ongoing)
Based on what you learned during reintroduction, create a personalised long-term diet that avoids your confirmed trigger foods while including everything else. This is not meant to be overly restrictive — the goal is to eat as varied a diet as possible while avoiding the specific foods that cause you problems.
Revisit your trigger foods every 6–12 months. Intolerances can change over time, and foods that previously caused issues may become tolerable again, especially if your gut health improves.
Common Elimination Categories
Which foods you eliminate depends on your suspected triggers. Here are the most commonly eliminated food groups in the UK, along with what they include and common alternatives:
| Food Group | What to Eliminate | Safe Alternatives |
|---|---|---|
| Dairy | Milk, cheese, yoghurt, butter, cream, ice cream, whey protein | Oat milk, almond milk, coconut yoghurt, dairy-free cheese, olive oil |
| Gluten / wheat | Bread, pasta, cereals, biscuits, cakes, beer, soy sauce, couscous | Rice, potatoes, oats (gluten-free), quinoa, buckwheat, rice noodles |
| Eggs | Whole eggs, mayonnaise, cakes, pasta (some types), battered foods | Egg-free mayo, flax eggs for baking, egg-free pasta |
| Soy | Soy sauce, tofu, tempeh, edamame, soy milk, soy lecithin (in many processed foods) | Coconut aminos, other plant milks, other plant proteins |
| FODMAPs | Onions, garlic, wheat, some fruits, beans, lentils, lactose | Low-FODMAP vegetables (carrots, courgette), rice, firm tofu, lactose-free dairy |
| Nuts & seeds | Tree nuts, peanuts, nut butters, nut milks, sesame | Oat milk, sunflower seed butter (if seeds are not eliminated), coconut |
| Nightshades | Tomatoes, potatoes, peppers, aubergine, chilli | Sweet potatoes, carrots, squash, courgette |
Start targeted, not broad
If your food diary suggests a specific trigger (e.g. dairy), start by eliminating just that one group. A more targeted elimination is easier to follow, less disruptive to your nutrition, and gives clearer results. Only do a broad elimination (multiple groups) if directed by a healthcare professional.
Timeline: What to Expect
Here is a realistic timeline for a standard elimination diet:
| Week | Phase | What to Do |
|---|---|---|
| Week 1–2 | Preparation | Plan meals, stock your kitchen, read labels, tell friends and family |
| Week 3–6 | Elimination | Strictly avoid trigger foods. Track food and symptoms daily. Expect some adjustment in the first week. |
| Week 7 | Assessment | Review symptoms. Have they improved? If yes, begin reintroduction. If not, consult your GP. |
| Week 8–14 | Reintroduction | Add back one food group every 5–7 days (2–3 days eating it, then 3 days observing). Track everything. |
| Week 15+ | Maintenance | Eat freely except for confirmed trigger foods. Retest triggers every 6–12 months. |
Some people see improvement within the first week of elimination, especially with digestive symptoms. Others need the full 4–6 weeks, particularly for symptoms like skin issues or fatigue that are slower to resolve.
How to Track During an Elimination Diet
Accurate tracking is essential. Without it, you are relying on memory and guesswork, which is exactly how trigger foods go unidentified in the first place.
What to record every day
- Everything you eat and drink — including brands, quantities, and preparation method
- Symptoms — type, severity (mild/moderate/severe), timing, and duration
- Symptom-free days — noting when you feel well is just as important as noting when you feel unwell
- Other factors — stress, sleep, exercise, menstrual cycle, illness
NutraSafe can help you track this — the elimination diet tracker is designed for exactly this purpose. Log your meals with barcode scanning, record reactions with severity ratings, and review your complete history when it is time to assess results or visit your GP.
Label reading is essential
During elimination, you need to read every ingredients label. Many eliminated foods appear in unexpected places: dairy in bread, soy in chocolate, wheat in sauces, eggs in pasta. A food intolerance tracker with barcode scanning makes this significantly faster.
When to Involve Your GP
An elimination diet is a powerful self-help tool, but there are situations where professional guidance is essential:
- Before you start — the NHS recommends consulting a GP before any restrictive diet, especially if eliminating multiple food groups
- If you suspect an allergy — allergies (as opposed to intolerances) require proper testing; do not try to diagnose them yourself
- If symptoms do not improve — persistent symptoms despite strict elimination warrant further medical investigation
- If symptoms are severe — significant pain, blood in stools, rapid weight loss, or difficulty eating require prompt medical attention
- For children — elimination diets in children should always be supervised by a healthcare professional to ensure adequate nutrition for growth
A registered dietitian can be particularly helpful during an elimination diet. They can ensure your restricted diet still meets all your nutritional needs, help you plan meals, and guide the reintroduction process. Your GP can refer you to an NHS dietitian.
Bring your data
If you have been tracking your food and symptoms with NutraSafe or another diary, bring this data to your GP appointment. Detailed records make it much easier for your doctor to help you, and can save several rounds of back-and-forth.
Staying Nourished During Elimination
One of the biggest concerns with elimination diets is nutritional adequacy. Removing food groups means removing nutrients, so planning ahead is important:
- If eliminating dairy — ensure adequate calcium (fortified plant milks, leafy greens, tinned fish with bones) and vitamin D
- If eliminating gluten — replace lost B vitamins and fibre with rice, oats, quinoa, and plenty of vegetables
- If eliminating multiple groups — consider a multivitamin supplement and track your micronutrient intake using an app
NutraSafe tracks vitamins and minerals alongside calories and macros, so you can check that you are meeting your daily requirements even with a restricted diet. If your intake of any nutrient drops significantly, the app will help you spot it early.
Track Your Elimination Diet with Confidence
NutraSafe helps you log meals, scan labels for hidden ingredients, track reactions, and monitor your nutrition throughout every phase of an elimination diet. Free to download.
Download NutraSafe FreeFrequently Asked Questions
How long does an elimination diet take?
A full elimination diet typically takes 6–12 weeks. The elimination phase lasts 2–6 weeks (until symptoms improve), followed by reintroduction which takes 4–8 weeks as you test one food at a time for 3 days each with gaps between.
Should I see a GP before starting an elimination diet?
The NHS recommends consulting your GP before starting any restrictive diet. This is especially important if you suspect a food allergy (as opposed to intolerance), are pregnant or breastfeeding, have a history of eating disorders, or are considering eliminating major food groups.
What foods should I eliminate first?
The most commonly eliminated food groups are dairy, gluten/wheat, eggs, soy, and nuts. If you already suspect a specific trigger from your food diary, start there. Otherwise, a standard elimination diet removes the most common trigger foods simultaneously.
Can I do an elimination diet while still eating well?
Yes, but it requires planning. Focus on whole foods you can eat: vegetables, fruits, rice, oats (if not eliminating gluten), lean meats, fish, and seeds. An app like NutraSafe can help you track your nutrient intake to ensure you are not missing vital vitamins and minerals.
What if my symptoms do not improve during elimination?
If symptoms persist after 4–6 weeks of strict elimination, the foods you removed may not be the cause. Consult your GP, who may refer you to a gastroenterologist or dietitian for further investigation. There may be a non-dietary cause for your symptoms.
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Last updated: February 2026