In general, if you're hungry, eat. If you aren't, don't. A few random thoughts.
1) Are you really hungry that early? (Like, would a couple glasses of water squash it out?)
2) When you eat breakfast, are you hungry for it? If not, maybe breakfast later in the day will push back your eating schedule to where you don't want to snack. I started pushing breakfast back a couple of weeks ago because I take medicine in the AM that needs to be on an empty stomach and needs to be taken with a ton of water. I too wake up around 4:00 most mornings. What I've found for me is that when I take my medicine around 4:30 or 5:00 with a couple of bottles of water, I'm usually not hungry until 6:30 or so. I typically eat lunch 6 hours or so after that and dinner another 6 hours later depending on when I'm hungry. I typically don't snack unless dinner is small, and even then a handful of nuts usually does that job.
Personally, I find a chicken breast on top of a gigantic salad with olive oil more filling than a chicken breast with the same amount of olive oil. A dry salad with olives, cucumbers, bell peppers and broccoli doesn't have a lot of caloric content, but it will fill your stomach. Bear in mind too that leafy greens take a while for your body to digest. As far as speed goes, I typically down a meal in about 5 minutes and get back to the business of doing whatever it was I was doing. But that's just me.