You body may be fighting a food or food ingredient such as green pepper or MSG or salt and you may feel fine. As you get older the strength of your immune response, or the consequence to your body of the bad ingredient, for example, salt, will, however, probably increase. Your allergic reaction or negative bodily response will gradually become apparent and if you do not take action you probably will experience health issues that you could have avoided. You may die prematurely from a disease, you never knew you could get. Yes, it is frightening, and yes, you need to be aware of the very real risks that your life is being exposed to daily, without protections of being aware of the danger. Very very bad!
I say that you may be able to avoid premature death, but I am not sure because of the weaknesses in national and international food policies. You may be deaded without ever knowing you were ill.
Wikipedia distinguishes food allergies from food sensitivities.
http://en.wikipedia.org/wiki/Food_allergy
This allergy food sensitivity thing is largely a question of degree and how your body responds to something it does not like. Normally, an allergy response occurs when the body can actually respond to a protein it wants to fight and the consequence could be death. Bodies can end up fighting themselves because of foods that trigger immune responses. Meats can be containers for such ingredients without you being told.
Our food now contains many proteins that were much rarer only a few years ago. The protein in Aspartame the sweetener phenylalanine is an example. This is not to say that your body will fight phenylalanine, but this sweetener might present a health issue for you.
http://www.sweetpoison.com/phenylalanine.html
I only sight Aspartame as an example, but what if what is poisoning you is a protein found in wheat. Lots a new wheats are being created by corporations and the proteins or molecules in the wheat may cause you an allergic reaction or sensitivity. This is very serious because you think you are eating ordinary wheat when you are eating something that could potentially kill you, or at the very leapt shorten your life.
Because food policies are being dictated by the huge amounts of money spent by large corporations to influence government policies, you may live in a country that is unprotected. In Canada, certain wheats were banned because the scientists there were concerned about the health of consumers of those wheats. The same wheats are grown in other countries and exported worldwide. How do you know you are not being poisoned today by the wheat you get in your cereal?
Will ye no think kindly on those who would be your friends! May the sun shine with your thoughts, today, and happiness grow in your heart! May you allow yourself some peace of mind.