I heard they eat things sweet and natural like apples, raspberries and bluberries. I think they also eat bread.

From Faery Facts (Fairies) (http://www.afaeryhunt.com/fairy_facts.htm) --

Q. What do faeries eat?

A. Faeries love natural foods, nothing artificial or junky. Pixie pears and mallow fruits are among their favorites. They especially love sweet morsels and are also fond of foods made with the spice saffron. Faeries are very fond of honey cakes, honeyed milk, plain milk and sweet butter. If you place a bowl or these faery tasty morsels just outside your kitchen, they will not be able to resist the treats. Don't be fooled into thinking they didn't have a feast if the food looks untouched. The faeries may have taken nourishment from the food's essence.

This site will answer all your questions about fairies (even about their bathrooms) --

Answers From a Real Fairy (http://www.fairies-secrets.com/real-fairies.html)