A food intolerance is different to a food allergy. A food intolerance is an inability to digest a particular food, which results in an adverse reaction occurring in the body. A food allergy is a response to a food which involves the immune system and is potentially life threatening - an example of this is anaphylaxis.
Food intolerances should not be taken lightly. Although the effects are not always immediate, undigested foods will cause damage to the cell wall lining in the gut which can result in leaky gut. Once this occurs, undigested proteins can leak into the blood stream. The immune system sees these proteins in the blood stream as invaders and will produce antibodies to attack them, to protect itself. This response causes systemic inflammation which leads to multiple problems, and it can end up turning these intolerances into allergies. Not to mention there is the discomfort you feel such as bloating, gas, diarrhoea or constipation. Food intolerances can also be responsible for headaches, mood disturbances, skin issues, poor energy, behavioural problems in children and many other problems.
The good news is that food intolerances are not necessarily forever. Often it is only one or two foods that are the problem, but these problems are leading to other food intolerances. The best way to work this out is to eliminate certain foods or food groups for 2-3 weeks, work on healing the gut and then reintroduce them one by one to find out which is the problem food. Symptoms are monitored using a diet diary. We have many tests available to determine which foods are the most problematic and I think in this day and age, it is a good idea to make use of these tests rather than attempt the traditional elimination diet. Either way, the idea is to eliminate the problem foods to heal the gut and calm the immune system, and then reintroduce them slowly.
I do know how difficult this is! I have gone through this process and I know what it is like. It does make eating out challenging, and you do have to cook for yourself mostly during the elimination phase. Learning to eat differently to the way you have been your whole life is not easy. Think of it as a chance to nourish yourself, expand your knowledge and give your body what it loves. Also, once you are through the other side and have eliminated the symptoms, it ultimately leads to you being able to eat more foods without problems.
This is also important as restrictive diets can lead to nutrient deficiencies and they impact the diversity of the gut microbiome. Your gut needs lots of different kinds of bacteria to flourish, and if it is not getting the right foods to feed these bacteria, they will die off and these imbalances can continue to give you the same problems. So it really is worth investigating (with the assistance of a professional who understands this process!).