It is time to see if personalised dieting will work in normal life. The volunteers have been given one of three diets to follow - based on their genes, their hormones and their psychology. But now they are back at home, trying to stick to their personalised diets with all the stresses and temptations of real life. Dr Chris van Tulleken and Professor Tanya Byron discover how our genetic makeup can make temptation difficult to resist, how understanding the brain reveals what makes us comfort eat and what science can tell us about why we make disastrous food choices.

Boxing, 'the poor man's sport', has long given kids from America's roughest neighborhoods an opportunity to escape violence with violence. But with success in the ring comes new fights for which there is no training: champions are made and broken in the blink of an eye, and young men thrust into the spotlight are often ill-equipped for the fame, fortune, and hangers-on that accompany a title belt". And for many, the toughest bouts are fought during retirement, when health and financial issues begin to mount. Built around the stories of heavyweight legends as Mike Tyson, Evander Holyfield and Bernard Hopkins, We will examine their lives in and out of the ring.

So far the volunteers have successfully been losing lost weight, but now the honeymoon period is over. It is the final two months of the diet, and their minds and bodies are fighting back. Dr Chris van Tulleken and Professor Tanya Byron find out if the new personalised diets will help them stay on course, and the experts reveal the scientific secrets to permanent dieting success.