I am allergic to peanuts, although I am not bothered by "things processed in the same plant." I often spread almond butter on spelt bread, and eat it during or after a ride. I echo the hard boiled eggs. I tend to get a little weird at mile 40. This is why I crashed into my DH on our failed century last fall. I also noticed it on my birthday ride of 61 miles, when I almost didn't stop at a stop sign. I just need to eat more.
I use Shot Blocks on long rides, which really help me, but I really need to eat more consistently on rides. Right now, I use Lara Bars, too, but somehow, they don't fill me up the way other bars do. Of course, they have less calories and other bad things.