Do you often feel sick after meals? Do you fear eating out just because you can't tell which meal, which time, which day will trigger unpleasant symptoms? You're not the only one. You may experience a food intolerance: a condition which is similar to food allergy, although not as much severe.

To break down different types of food, your body needs certain enzymes. The absence of these enzymes can cause a food intolerance. A reaction to a food your body does not tolerate can come later than a reaction caused by a food allergy, so the identification of intolerance "trigger foods" can be difficult.

You may have heard of two of the common food intolerances, lactose intolerance (in which the body cannot process dairy products) and gluten intolerance (in which the body cannot process wheat products, also known as gluten). Several other types of intolerances exist, as well, and all of them are associated with unpleasant symptoms.

The symptoms of food intolerances may include diarrhea, constipation, flatulence, irritable bowel syndrome, fatigue, and pain. The best real way to prevent these symptoms is simply not to eat the foods in question - and the way to discover just which foods these are is to take a food intolerance test.

The elisa (enzyme-linked immunosorbent assay) food test is a common food intolerance test, which involves having blood collected-usually from the fingertip-either at home or in a doctor's office. A lab then analyzes this sample for reactions with certain foods. A strong reaction will cause many IgG antibodies to be present in the blood; the more antibodies there are, the stronger the reaction will be.

Results from the food intolerance test will show the amount produced and by which types of food. All of the different types of scales measure about the same thing, which is the production of antibodies. It will be quite clear which of the foods, if any, caused intolerance reactions; research has shown this type of test to be quite reliable in hunting out the source of these reactions.

If you find out you have a food intolerance, there are several steps you can take. The most obvious step is to remove said food from your diet - this can range from simple to quite difficult, depending on the food. For the more common intolerances, such as dairy, manufacturers have marketed 'safe' products, but for others you'll simply have to read ingredient labels and ask questions. This may be inconvenient at times, but it's certainly better than the symptoms. In the end, a food intolerance test is well worth the cost and effort.