jkaunisv
To be clear, this is my snacking hierarchy, not my entire diet. I do have regular meals as well that are more balanced.
I do actually go for carrots and broccoli before apples and bananas quite often. I like them a lot. Often I end up eating just a few raisins before it's time for my next actual meal (which is balanced and full of veggies).
What are the more interesting and nutritious foods you're talking about? I would like to try them!
In this example it's a personal aspect of how they fit into my life - the games I tend to play these day aren't very mentally engaging. Tends to be something I've played so much it's routine & reflex (CounterStrike) or really easy that I play for other reasons (Pokemon).
I actually 'invented' the snacking hierarchy because of CounterStrike. Time between rounds was brutal for eating goodies.
I don't really put a time frame between levels. It takes a lot for me to feel full so that hasn't been something I've paid attention to. When I say it takes a lot I mean it...I've been denied further service at all-you-can-eat restaurants. For me the craving isn't really about fullness, it's just a desire that can often be sated with water and veggies.
I've heard about a 20 minute gap between being full and your stomach letting you know that, so I'd probably put 10 minutes between each snack. But I'm not scientific about this at all so I'm just throwing that number out there.
The system works for me because I end up satisfying the craving on healthy stuff before I can get to the unhealthy a lot of the time. That said, everything I write about is based on personal experience and I just try to distill some of the general tips that anyone could use.