Ecstasy fucks up your hpa axis and drains your adrenals of cortisol. In a rave setting your body increases cortisol production 800%. That's insane, but necessary from the ecstasy, lack of hydration, and on top of that the all night dancing. which is why cortisol rises is to buffer negative effects of stress.
And when your adrenals aren't working properly you tend to be on the skinny side. It has something to do with.. all your body's energy (so all the food you're eating and fat you have) goes towards making more cortisol to block stress. I'm not sure if that is the exact way it makes you lose weight, think I just read that somewhere. But adrenal insufficiency is definitely contributes to weight loss.
Like it's interesting because excess cortisol causes weight gain. But when your cortisol levels become abnormally low you start to lose weight... and even when you stuff your face full of food, you don't gain anything.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2826870/
