Each cereal has its own inherent characteristics which must be taken into account to insure a pleasant breakfast experience.
Now there's the "easy" cereals that are not possible to over-eat. Puffed Whatevers, Rice Krispies. It's all air wrapped in very thin flour. Keeping them in the bowl when you add milk - now that's the trick.
Shredded wheat is an honest cereal. The bowl is immediately at the right serving. It's either the one big bale or a few of those smaller pillows with frosting. Either way, the bowl's full and you know when to stop.
But the most insidious cold cereal known to humankind is:
Grape-Nuts.
Pour a "normal" bowl of Grape-Nuts. Add milk. Now, begin to eat.
Chew-crunch-chew. They have a nutty goodness. Chew-crunch-chew. They taste healthy.
20 minutes later: My jaw's getting tired.
15 minutes later: I think I'm losing teeth enamel.
10 minutes later: Is this stuff growing?!
5 minutes later: Is that - is that the bottom of the bowl?!
3 minutes later: Here, boy . . . c'mere, boy . . . good dog!
Done.