Why cant i gain weight?

read before you say its to do with metabolism.

i dont have "small" genetics. my mum is a big woman and my dad is normal. everyone on my mums side is big. my mum has trouble losing weight and puts weight on easily.

when i was 14 i was over weight. i tried everything to lose weight, but cause of what i thought is genetics (i take after my mum) and my metabolism i gained. when i reached 17 i lost all my weight through extreme exercise and diet, i got way too skinny.

soo heres the thing:

ive been binge eating for the past 4 weeks and havnt put much on. im talking about eating whole pizzas and king sized blocks of chocolate all in one go. ive put a little on, but you cant really tell.

how is this possible? we have slow metabolisms in our familyWhy cant i gain weight?
Sometimes diet and working out just isn't the be-all and end-all, because there can be excess weight just sitting around in the pipes. It's not body fat, therefore it cannot be burned off, nevertheless it can be flushed out, just by taking a diet supplement. http://dumert.besthealthpro.info has a risk free offer offered right now, I gave it a try and melted away seventeen pounds!! Who says there's no magic bullett? LOL!!!Why cant i gain weight?
Why are you trying to put on fat? Eating this much isn't even healthy. Just work out and gain muscle..Why cant i gain weight?
It is dangerous to push your body to either extreme of the weight scale, and it can be difficult for people to get back to a good, healthy, stable weight. Binge eating can result from semi starvation periods. It's also very unhealthy and stressful on the body. The best way to reach a steady stable weight is to eat a variety of foods at regular intervals throughout the day. Because of the overweight problem in our society, few people realize just how difficult it is to have problems with underweight and disordered eating. Please seek help if you need to. College counseling centers can often point people in the right direction.