The elimination diet

This type of eating plan involves removing specific foods or ingredients from your diet that you suspect may be causing symptoms. It doesn’t work for everyone and can be a long process so you should talk to your GP first. It’s also important to bear in mind that you can end up cutting out foodstuffs and still be left with symptoms that may be caused by another aspect of your diet.

• Talk to your friends or family about what you're doing.
• Read food labels carefully and work out what you can and can’t eat.
• Keep a symptoms diary before you begin the diet.
• Keep a food diary to record the foods you are eating each day.
• Be prepared: at the beginning you’ll feel tired and listless.
• While following this diet, eat other foods that provide the same nutrients as those you’ve eliminated.

This kind of regime is not suitable for anyone with a severe allergy, such as an allergy to nuts, as it can provoke a strong and dangerous reaction. If you have ever had a very bad reaction to a food, such as violent sickness, you should not be doing this diet. Nor is it suitable for people with particular conditions, such as Crohn’s disease or atopic eczema.

It’s a good idea to cut out all the drinks and foods that are full of additives and stimulants before starting the diet, such as coffee, alcohol and very sugary foods.

How to begin
Keep a full diary of both your symptoms and your diet so that you can compare the changes later.

Exclude all the foods that you would normally eat regularly, such as cheese, bread, butter or oranges. If, for example, you normally eat a lot of cabbage, you have to exclude foods that are closely related, such as broccoli or brussels sprouts. If it's oranges, also exclude lemon and grapefruit.

It’s not easy to cut out all your favourite foods, but you should be able to find at least 10 other foods that you can eat over a period of 7 to 10 days. They include the following:

• Fruits and vegetables
  These should not be the ones you eat regularly. Consider mangoes, pears, nectarines, leeks, parsnips and pumpkin.
• Starchy foods
  As you’re excluding bread and wheat, this becomes harder, but you have to include some starchy foods. Rice is good, and try more unusual grains such as sago, millet or buckwheat.
• Meat
  Go for meats you don’t normally try, such as venison or pheasant.

Unfortunately for vegetarians, both soya and Quorn must be avoided, but put nuts on the list as a source of protein.

The first week
Be prepared for this first week to be hard: you may feel lethargic or suffer headaches or a migraine.

If you don’t experience any change in your symptoms after 10 days, food is probably not causing your problems so you shouldn't go on to the next stage. Again, make sure you talk to your GP about this. 

Re-introducing foods
Allow about two months for this stage. It has to be done methodically, or it won’t work.

For the first two weeks, start to eat the foods that you enjoy but are not the main part of your normal diet, such as certain fruit, vegetables and meat.

Test one new food each day, and make sure you don’t over-eat.

Record any reaction to the food.

If you get diarrhoea and you're unsure which food caused it, drop all the foods that you suspect, and re-introduce them later for a three-day period.

Wheat and milk products should be left until the end.

Doctors suggest that you shouldn’t start with bread, because it contains yeast (which can cause an intolerance). Instead look at re-introducing a cereal.

The final stage
Food intolerances could be caused by common additives found in food, so towards the end of the eight-week period, introduce packaged foods to see if these cause a reaction.

Don’t continue the diet for more than eight weeks. Talk to your GP about what to do next.

What next?
For anyone who has successfully identified the food group that is making them ill, the usual habit is to cut it out completely.

The strange thing about food intolerances is that you can grow out of them. Within a year, you may find yourself able to eat something safely again. But even if this is the case, it's still a good idea to limit amounts.