Seriously, Remeron. I was 90 pounds 10 days ago, since going on Remeron, I eat till I'm sick & eat more. I have major GI issues, pain issues, & health issues & it doesn't even matter. Today I'm 104 pounds, so in 10 days I gained 14 pounds. I went from an average of 750 calories a day to an average of 3500, based on the calculations in my spreadsheet. Definitely not healthy eating or living, but if your just looking to put on weight it works.
The side effects can be a bitch & in my case are, I didn't choose to go on this medication & I'm also experiencing opiate withdrawals due to a Hospital fucking my medications all to shit, but even with the stomach cramps, pretty much liquid stool, frequent bowel movements, nausea & the like I still can't stop eating. Personally I think that Remeron (Mirtazapine) is fucking evil, as TCA's, well it's a TeCA & NASSA but still, if you want something that will basically force you to gain weight Remeron is it.
I am being forced to eat till I'm sick & eat some more, it's horrible I can barely function let alone get anything done, but hey I'm gaining weight... Doctors logic can be royally fucked. Though in my case its a long story you'd have to read some other threads I've posted in to have a better idea as I don't have the time or energy to explain it atm.
But if all you care about is putting on weight Remeron will cause you to gain weight, I've never seen anyone take it & not do so. Most people I know gain 30-50 lbs, I'm hoping to stop taking it far before that happens.
Anyways I digress, but if you don't give a shit about health or side effects or anything else besides packing on pounds Remeron (Mirtazapine) is what your looking for.
BTW don't mean to be a dick but just giving the guy an honest answer, might not exactly fit Healthy Living but it answers the question. More than likely I'm just kinda bitter at being forced to take a medication I don't wanna be on.
Don't mean to offend or violate the forum rules in anyway, so I shall leave it at that.