The brain performs more local gluconeogenesis and otherwise utilizes a stable supply of ketone bodies

I feel like sugar in general makes me tired and makes it difficult to concentrate. Sometimes (though rarely) I consume sugar in the evening to make me tired.

I can't help but eat candy if it's available, so I just learned not to buy it in the first place.

From personal observation (I think it is even backed by research) not having enough sleep causes craving for sweets/junk food.

Sucrose is what bees crave so its pull must be deeply embedded in our reward system. I associate the high sugar consumption with short circuiting the reward system.

I had the same habit. You eat sweets -> blood sugar goes up and you feel energetic. Problem is, it also goes down very fast, at which point you feel sleepy and hungry at the same time.

Really easy to become overweight this way.