I have an 18 yr old, 10 yr old and a 14 mo old at home. I've also raised a now 23 yr old as well as another teen who lived with us for a couple of years when they were in their mid-teens. I used to have problems with one or two of the kids scarfing ALL of the sweets and leaving none for anyone else. This effectively screwed those that ate responsibly.
I developed a system whereby each person is allowed to order (via me, the grocery shopper) a snack item for the week. It could be anything from cookies, popcorn, gummy bears, ice cream, nuts, or a chunk of cheese to pudding or yogurt. But this snack was all they would get for the week. They had the choice of eating it all in one sitting or spreading it out for 7 days. If they took a snack belonging to someone else, they forfeited their snack for the following week in favor of the shorted person (who got two). They also have the same plan for drinks. Each person gets assigned drinks (usually soda/tea) and they have to use them sparingly or they will be drinking nothing but water by week's end.
I also stock the less expensive and healthier snacks for the family such as pretzels and apples/oranges. If they run out of their sweets, they can always eat the household snacks. Juice and Milk are provided in unlimited quantities.
I found that this system gives each person control over how much they want to eat at a time and still teaches them to save and conserve. They also learn to respect each other's property.
I am on a tight budget so meal planning is a big issue. I always serve home cooked, well balanced meals for dinner and everyone is expected to participate (or go hungry).
It has worked well for me so far
. They're all healthy and none appear to have any food issues (overeating/undereating/addictions/excessive tooth decay).
Stormie