How does bulimia keep you from gaining weight?

With bulimia, you only absorb about 35% of the calories and nutrients. Less calories = weight loss. But it is horrible for you. Throwing up is a function that our bodies have developed in order to get something out that isn't right, doing it constantly is awful on your body and has very, very serious side effects.

In short, no it's not like not eating anything. Anorexics eat just the amount of food they need to not pass out and usually don't get half of the nutrients that they need so their body steals it from anywhere it can get it resulting in massive amounts of weight loss. Bulimics still get some nutrients, but not all, so it much harder to detect a eating disorder unless you catch them in the act.

I am a personal trainer and have degree in nutrition