My kids are big eaters. One has a bowl of cheerios and 2 eggs, or an egg and sausage most days. The other a bowl of yogurt with raisins (bleah!) and a sausage or egg + sausage. Sometimes it's oatmeal instead of eggs, and sometimes they have a small amount of fruit. Both also have something at beforecare/school.
Lunch for the one I pack is a pb&j sandwich and some cut veggies, maybe half a cut apple. Dinner is a bit bigger - meat/beans, pasta/tortilla/rice (and seconds here usually), veggies, and fruits after.
No idea where all that food goes. My one kid is skinny, the other average. Not looking forward to teen years!