Do judges give out tougher sentences when hungry? A study too good to be true

From my experience, it's a delusion. The focus is there for some while, but the actual abilities decline very fast without you even realizing it because of this supposed clearness. It might be even that the clearness comes exactly because of your mind limiting itself to a shorter attention and horizon, removing all the complex and complicated things. It's basically being in the zone, but the zone itself is so limited that you might not do good work if you need to have a "big zone". Though, it depends on your type of work if this can be beneficial. But as a knowledge worker, I consider it harmful for my work.

> When I was a kid, I recall the teachers always telling us to have a good meal before a test. Even then I felt that was silly, as a big lunch always gave me brain fog.

Depend on the type of food, size of meal and how long before the test you were eating.

> "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.