Last summer my doctor diagnosed me as "pre-diabetic." This was a result of me constantly eating a shit ton of pizza, cookies, and pop tarts, and drinking a shit ton of soda. I have since completely cut out poptarts, mostly cut out cookies (just have some when my parents bake them, which isn't all that often) and cut way back on soda and pizza. I also exercised for a bit. My glucose levels are back in the normal range now.