This new study, published in Nature, and led by researchers from the University of Cambridge alongside teams from Queen Mary University of London, University of Bristol, University of Michigan and Vanderbilt University, has discovered the brain receptor behind that process.

It's called MC3R and is the crucial link between food and sex development and growth.

"It tells the body we're great here, we've got lots of food, so grow quickly, have puberty soon and make lots of babies," said Prof Sir Stephen O'Rahilly, study author, from Cambridge.

"It's not just magic - we have the complete wiring diagram for how it happens."