My daughter was quite chubby as a baby (rolls and rolls)and toddler. I enrolled her in dance class at age 3 and she stayed in it until she was 18. She thinned out at around age 5-6 a little. And was pretty much average throughout her school days. Now she is the mom of 2 and quite thin.
I remember when she was young, she wanted to drink milk after every bite she took. We started taking the milk away at mealtime, gave water instead. It is hard to restrict eating, so make sure you do not have sweets around or things that have no food value, like potato chips, etc. Give her smaller portions on her plate and let her decide if she needs more. When she is done, let her have a glass of milk.
You could also start taking her on walks after dinner, even if it is just around the yard. Or play games that require getting up and moving, like tag.
As for the bedwetting, I wet the bed until I was about 5. I can remember being very baffled by it. I tried very hard not to. I tried to stay awake so I wouldn't wet the bed, next thing I knew I was waking up and wetting the bed. But, eventually I did quit. It may just take time.
Consult a doctor for both of these problems if you can't get them under control.