Geneticist Giles Yeo and his team assess five overweight volunteers, before putting them on personalised diets tailored to their bodies and brains.

Horizon interviews some experts and looks at the matters which can change our lives in the future, like: climate change, the future of transport, energy production, gene therapy, artificial intelligence, among other things.

A Cambridge geneticist dispels misconceptions about living with obesity and explores why the epidemic continues to expand across the UK and America.

Horizon tells amazing science stories, unravels mysteries and reveals worlds you've never seen before.