Sarah Cox was told by her doctor to lose weight because her BMI, or Body Mass Index, was too high. But the consequences of her doctor's weight loss plan left the 35-year-old sick and hospitalised, as she battled an eating disorder for two-and-a-half years. Now, there is renewed scrutiny of the use of B-M-I as a measure of an individual's health. The tool has been used by doctors for more than 50 years to measure an individual's body fat, after it was first created in the 1830s by a Belgian mathematician [[Lambert Adolphe Jacques Quetelet]] who was not a doctor or a health practitioner. More evidence has since emerged about its efficacy - and a group of experts from around the globe are proposing new definitions of obesity that consider a spectrum for how excess fat may or may not impact an individual's health. In this episode of Weekend One on One Catriona Stirrat speaks to Sarah Cox about how her doctor's reliance on BMI led to the frightening deterioration of her mental and physical