Eleven-year-old Aiyesha, who weighs almost 12 stone, meets nine-year-old David, who weighs a miniscule three stone 12 pounds. Aiyesha is double the weight she should be for her age. And that's because her mum is scared of her daughter's explosive temper. Can a reality check from 16-year-old American teenager Brianna, who weighs 25 stone, convince Aiyesha to change her terrible diet for good? Nine-year-old David exists on a diet of processed foods and his favourite chocolate milkshakes. With her son refusing almost everything she cooks and shunning most fruit and vegetables, mum Paula is seriously concerned that his fussy eating will turn into something far more serious.