sugary cereal first-hand
So we generally try to stay with cereals with less than 6 grams of sugar per serving. Sweet foods are easy to like, and tend to replace other foods and worsen variety, and thereby nutritional quality. Meaning, kids will often eat only sweet things if given the chance. (It's why desserts and sweets are treated differently with the Division of Responsibility.)
I watched this first-hand with our first box of Frosted Flakes. I took M with me shopping, something I try not to do, and she asked for frosted flakes. I had already said "no" to ding-dongs and a few other things (I much prefer Ghirardelli brownies anyway, which M also likes...) and I wanted to see what happened, so we bought a box.
We had the cereal on offer the next few mornings, and literally ALL M ate was dry frosted flakes. Nothing else. Not enough variety, not enough fat or protein to sustain her and our mornings were more difficult. I didn't explain that she needed to eat other things, but after 3 mornings of this, we said, she "could have toast, eggs or Kix or Oat Squares today." She chose the toast and some Oat Squares and milk and was fine. I expected a big battle for the FF's but didn't have it.
It was an interesting experiment. We might offer it on occasion, when she's home and I know I can offer a balanced snack or lunch, but it definitely confirmed the sweets-kill-variety if not managed appropriately.
What have you noticed with sugary foods?