Body Clock: Does eating late make you fat?
12 May 2014 Last updated at 09:26 BST
We all know the importance of calories in affecting our waistlines, but does it matter when we eat them?
The BBC's Day of the Body Clock is charting the large changes that take place inside in our bodies throughout the day.
Our health and science reporter James Gallagher explores whether eating against the body clock can make you fat.