Foodaholic Rob Gillett goes head to head with foodphobic Hayley Payne in the Feeding Clinic. And Dr Christian goes for a ride on a supersize ambulance in America's fattest town.

Rob Gillett's obsession with donuts and cream cakes has seen him eat his way to an enormous 35 stone 10 pounds. While on the other end of the scale, for busy-bee Hayley food isn't a priority - which has left her weighing in at just 6 stone 12 pounds.

And the warning signs of bulimia are revealed through the eyes of 20-year-old Lucy Glover, who regularly binges and purges on a staggering 8000 calories at a time.