Horizon investigates the idea that the best way to lose weight successfully is a personalised approach, diets tailored to our individual biology and psychology. In a groundbreaking experiment, Dr Chris van Tulleken and Tanya Byron join a team of experts to put 75 overweight volunteers on diets designed to tackle the specific reasons why they eat too much. The volunteers are put through a series of tests at a residential clinic to understand how their genes, hormones and psychology influence their eating behaviour. They are then put on the diets the experts believe are best suited to them. Can science succeed where other diets have failed?

Documentary which tells the story of the theory of evolution by natural selection which is now scientific orthodoxy, but when it was unveiled it caused a storm of controversy. Many people criticised it for being short on evidence and long on assertion and Darwin, being the honest scientist that he was, agreed with them. He entrusted future generations to complete his work and prove the essential truth of his vision. Evolutionary biologist Professor Armand Marie Leroi argues that, with the new science of evolutionary developmental biology (evo devo), it may be possible to take that theory to a new level - to do more than explain what has evolved in the past, and start to predict what might evolve in the future.