When you absolutely have to have a snack at 1 am or you won't get to sleep.
A combination between having a snack and having breakfast. Such as a combination between Breakfast and Lunch which gives you brunch.
John: Honey where did you put the leftover turkey?
Susan: What do you want with leftover turkey at 1 am?
John: It's the snackfast crave calling, babe.
One whose diet mainly consist of chips, cakes, cookies, soft drinks, French fries, hamburgers, hot dogs, pizza and cold cereals; and just so happens to stay in good shape. (Brand usually does not matter when selecting foods.)
Rick is the ultimate snackatarian. His daily meals usually include cookies and Sprite for breakfast, pizza, coke and chips for lunch, and a bowl of Cap'n Crunch for dinner. Only a snackatarian can eat like that and never seem to gain weight.
I went on vacation last year and ate 2 boxes of pop tarts, a family size bag of cheetos, half a box of chips ahoy cookies, and a pound of sour patch kids, and that was just in the car on the way there! It ended up being a real snackation...