We find out if it's possible to revise for exams, become a mechanic or pick up a new language in your sleep! Do those CDs really work? Plus, we ask how many calories our bodies actually absorb from the food we eat. Like this podcast? Please help us by <a href="https://www.thenakedscientists.com/donate">supporting the Naked Scientists</a>

Are all the calories in food absorbed?

Each week we set out to solve one of the world's weirdest, wackiest, funniest and funkiest scientific puzzles. And along with the answer there's a brand new question to think about for next time...