It's a true and false statement. Your metabolism will slow down as a preservative measure so will burn less fat and require less calories to run on. It'll eat your muscles first, which will slow your metabolism down too cause muscle burns more than fat. Then yes, it will move on to fat and you'll get thinner. But by then you already need very few calories and you are drained all the time. I can show you a pic if you want. I suffered from an ED fornearly 10 years. I began my recovery when I got pregnant. I knew I needed to eat for the baby. Make no mistake, it wasn't a large amount. a small bowl of cereal for breakfast, a salad with fat free dressing for lunch. 4 triscuits and fat free cheese slice for snack and small dinner. 20lbs I gained in about 9 weeks. I'm not quite sure how I was surving prior to that as aside from getting a snack here or there, all my calories came from beer pretty much. Got saved and got better. But it's a hellish road I wish on no one. I use to know the cal count in everything, couldn't take even 1 bite of food without stressing and would immediately feel fat bubbling up under my skin. Or so I thought. There's better, more lasting and deffinantly more healthy ways to lose wieght. ED's only lead to sickness and self hatred.