By the middle of January many people struggle to keep up their resolutions to be more active. The result is that the UK wastes nearly ú600 million a year on unused gym memberships. But new science has the answers. Medical journalist Michael Mosley teams up with scientists whose latest research is turning common knowledge about fitness on its head. They reveal why 10,000 steps is just a marketing ploy and that two minutes of exercise is all a person needs each week. They discover how to get people to stick to their fitness plans and what exercise can actually make everyone more intelligent. Whether its for couch potatoes who hate the thought of exercise, someone too busy to consider the gym, or even for fitness fanatics who are desperate to do more - science can help everyone exercise better.

Dr Xand van Tulleken investigates whether claims about negative effects of carbohydrates on health are true. The film looks at cutting-edge research into a possible link between carb consumption and infertility, and it investigates whether genetic changes are taking place when passing eating habits on to children. Xand and a team of volunteers attempt to guess how much sugar a selection of common foods each releases into the bloodstream. The film also sets out to examine whether it is possible to eat carbs in a way that is much healthier. Scientists have discovered that starchy carbs like pasta, rice and potatoes can be changed in a very simple way to make them healthier, and there is a surprise in store for Xand when he heads to the gym with his favourite carb-filled sports drink. The programme also teams up with a Merseyside GP to trial a healthy-eating plan which asks people to swap 'sugary' carbs for more fibre. The results after just two weeks come as a surprise.