Stop the Strech Marks!!!

How do i stop getting stretch marks? i've been putting on coco butter like whoa, I feel like a roll. But I am only 14 months and have started to see a faint line here and there and am freaking out. Please tell me I can stop these. I was already very body cautious before getting preggo and now I am so worried I will never get to where I want to be after having this baby.

Also if you are already "technically" overweight at the beginning of your pregnancy and they say you should only gain 10-15 lbs, how doable is this? I feel like a lot of books I've read women say they gained 40-50lbs, Now that seems like something I would do, but according to the dr, I shouldn't but how can I really control a craving or not eat when i'm hungry?

Advice please!!!