I just got back from a 37 mile ride because I forgot to bring a bar to eat in case I got hungry. I stopped because I got hungry and I didn't want to ride hungry. I parked my bike in the garage, went inside to pee, and got a glass of water. Somewhere along the way, I lost the hungry feeling. I realized I wasn't hungry at all. Thinking this was bad, I got an energy bar and ate it. I also ate half a sandwich. Five minutes later I was absolutely FAMISHED. I ate the rest of the sandwich, a bowl of cereal, and another energy bar.
This whole incident didn't strike me as odd until I felt the urge to have a bowl of cereal. I was curious if anyone else has had these strange hungry feelings and what causes it.
My piss was also a deep yellow, which I have been told is a sign of dehydration, so I am drinking lots of water now.
I eat when I'm hungry.
I'm often not hungry immediately after finishing a ride, particularly if the intensity is higher.
On a 37 mile ride you likely burned at least 1000 Cals so it's not a problem eating after the ride to replenish what you burned. Although if you were trying to lose weight it sounds like you ate more than necessary.
I have had intense rides where my appetite disappears and I am force feeding myself to avoid a bonk in the middle of nowhere. Afterward it takes a bit for my appetite to come back but when it does I can eat more than I burned on a 5000 kj ride.
I don't take any food with me on rides up to about 30mi. I'm totally fine with no food, but all sorts of physiological changes happen when you stop entirely. I have friends that will ride 30out, stop at a restaurant for lunch and have a huge meal and then ride back. I have a small snack because I'm snacking a little bit along the way. I don't think it's odd to have a bit to eat and then get really hungry, but I'd suggest you take some cliff bars or whatever (just carbs) to snack on as you go so you keep your energy up. On long rides I start to snack right away. It's not like what you eat gives you energy right away. It takes an hour or two for the food in your mouth to be available in terms of energy so if you start eating after riding for two hours you are either on a very long ride or are not going to get much energy (that assumes complex carbs).
Yes, your dark pee is due to dehydration. You should drink a big glass or two of water an hour or two before you leave and then, if you're working hard, a bottle every hour or so. That's a rule I hear often but don't have any data to back that up. It seems I need less water today than I did two years ago.