Sounds a lot like me. Especially when I was a child, I was extremely underweight because of this. I rarely had any appetite to eat, and when I did, I got full after just a few bites. Talked to several therapists, no one was able to diagnose me.
Nowadays it's better. I eat as much and as often as possible, to the point of almost feeling sick, and I'm barely able to keep a healthy weight. Sometimes I wish I had problems with being overweight instead, since that's at least 10x easier to combat. Although, I bet life is easier being underweight than being overweight, as I've always been decently athletic with barely any training.
Why not just add speed limits to areas where higher speeds are an issue? That's been the approach to cars -- no car is limited to 140 kmh despite speeds above that are illegal pretty much everywhere...
Regular bikes can easily go above 15 mph as well, so why should this only affect e-bikes?