January is a miserable month and yet so many make it even more miserable by trying to give up some of life's great pleasures – such as alcohol. Three weeks in, how's it going?
Tired? Lethargic? In dire need of 40 winks? Join the club, says Grace Dent. But how to boost our energy levels without putting in too much effort? Plus, we ask a doctor, a finance whiz, a radio presenter and a chef how they get by on so little sleep