If 30 is a long distance for you, you probably will want a snack. When I started riding 30 would be hard without Gatorade and maybe a small snack. I was already running four days a week, so I had a good fitness base but 30 miles would wipe me out.

Four years later I will not eat on a 30 miler, I will however have one 20 oz bottle water and one 20 oz of something with electrolytes. I usually eat every two hours (in the normal area I ride this would be about 35 miles) because anything more tends to upset my stomach.