Harry

Welcome to healthboards.
Sorry about your problem but it can be serious because when undigested food is in your stool -- it means you are not properly absorbing necessary nutrients.
If this continus for any length of time it could affect your health in many ways. I think you need to be checked out by a Doctor.

Having said that ~~~ this is what I would do in the mean time!
At sometime you are going to have to develop a better diet plan. When you are young and healthy, the body is very forgiving but a poor diet will eventually remind you that you are only human and good health responds to what you eat/drink, exercise, and adequate rest. Choices you make are very important --- sooner or later?

You are not digesting your food properly--- it could be for several reasons -- your system is not putting out enough digestive enzymes -- you may need to take a digestive enzyme that is pretty complete type with each meal.
I use an enzyme -- Essential Enzymes by Source Natruals. It contains enzymes for protein, carbs, fats, cellulose and milk sugar-lactose.

Also, the friendly bacteria in your intestines may be out of balance--- your intestines contain over 400 different strains of bacteria. When the friendly bacteria get out of balance -- you don't digest well--
You can eat a good brand of yogurt and drink Kefir that contain lots of friendly bacteria. And, you can also take a probiotic suppement to re-colonize your intestinal tract to re-balance your friendly flora.

The friendly bacteria can get out of balance for alot of reasons--- here are some--- taking a round of antibiotics as well as other medications, intaking too much salt or sugary foods, too fatty foods, spicy food and even alcohol -- and too much stress can really mess up the digestive process.

I wish you well~~~Harry