I know all about Ana...and her sister Bella all too well. I will tell you this, it WILL destroy your life. It will effect your health, your vital organs, your bones, your teeth...the list goes on. The real kicker to it all, once you hit your goal weight and stop purging, stop popping diet pills like candy, stop using laxatives like they will never be made again...the weight comes back....sometimes doubled even. So you start the cycle again....then one day during a binge you get a shooting pain in your jaw....guess what? All that purging, all of that depriving your body of nutrition, has taken it's wear on the enamel and you broke a tooth.
Over time that cycle is gonna start shutting down your body and guess what? Your options are feeding tube or DEATH.
If you really wanna loose weight, do it the right way. Get on a sensible diet....roughly 2000 calories....more if your into sports....get to a gym and work with a trainer. Too pricey for ya? Order insanity and follow not only the exercise program, but the diet that is included and the pounds will fall off.
Btw, anyone who would actually tell you to go with the Ana/Bella diets, needs a bullet between the eyes.