>I don't know how so many people just sit still all day, with a big lunch too, then wonder why they feel tired in the afternoons.
One of the best periods I had in college was when I used to wake up around 0430, work out at home, take a shower, have breakfast (oeufs au plat, escalope/steak, and half a liter of milk).
I'd spend the day feeling great even though I didn't have lunch hour, just four 1h30 lectures from 0800 to 1430 as opposed to 1st and 2nd years 0800-1120, 1300-1630, with 10 minute pauses between each two lectures.
Full of energy and feeling great the whole day.