Like, do they eat well and exercise all the time? Whole wheats, like whole wheat bread and brown rice, are a type of whole grain. A reason is because when you skip breakfast, Teen girls with flat stomachs tend to be so hungry that you will overeat during snack time. And your brain knows exactly how to do that; junk food, candy, soda, etc… Are all things that will make you feel better temporarily. Find ways to avoid stress-related weight gain.