Part of having a big breakfast not only "breaks the fast" of not eating for 10-12 hours, but it helps you not eat so much late in the day. Carbohydrates "kick in" and help quelch hunger about 7-8 hours after you eat them. (So you if you find yourself hungry at 10pm, try eating carbs about 2 pm, assuming you have eaten at least 3 meals during the day.)