> "longer fasts – and thus, presumably, greater hunger"
As anyone who has fasted for probably any reason can tell you, the longer the fast the less hungry you are overall AFTER an initial peak. Meaning, miss a meal and you are hungry, miss two and you become very hungry, but miss X* amount of meals and your hunger actually decreases. At some point you can go for days without any hunger at all.
Similar things happen with OMAD (one meal a day) fasting, which is arguably very similar to the mentioned Ramadan, the body gets used really fast* to the new regime and you stop being hungry outside the normal meal hour(s).
* the time specifics depend on many things, mainly on the type of meals you eat before the fast (e.g. sugars/carbs = worse withdrawals) and multiple other factors, but overall seems to be true this peak hunger happens and then hunger decreases.