The two most useful health stories of the year.

1. This one, explaining why your brain will be sharper if you stay a bit hungry. Maybe you've been trying to lose weight, but feeling that it's always important to stave off any feeling of hunger, for fear you might become weak or dim-witted. No! The opposite is true. We evolved to perform especially well when we feel the need for food. Sate yourself, and you'll be duller. Using this information, invent a better weight-loss diet.

2. And this, about how the natural sleep pattern is to have a first and second sleep, with a wakeful period in between. Until I read this piece, I regarded this as an unfortunate sort of insomnia, and knowing that it is natural and that, years ago, people used the inter-sleep period to accomplished things has completely transformed how I think about sleep.