My hunger tends to vary on rides, depending on the mileage, intensity, time spent on the bike, and even the weather. Sometimes, I can end up being very hungry and taking in more calories, on a shorter (30-50 miles) but more intense ride. Then there are days such as today, where we did just over 100 miles (at a more casual pace) and all I had for food on the entire ride was 1 mini Luna bar (80 cal) at stop 1, and then a PB & honey sandwich (210 cal) and 1/2 banana (50 cal) at stop 2...and I was perfectly fine. I don't think fueling for endurance activities is an exact science. I think it's a lot of trial & error to figure out what works for you.