Is there a way to curb my 6 year old's appetite?

I know that sounds weird, but I'm struggling! Im a single mother and my daughter is stunningly gorgeous, but Im worried she is starting to put too much weight on. I would never dream of drawing attention to this but I want to make sure she is as healthy as possible. Ive upped her exercise to as much as possible, Ive cut out junk food, there is rarely any in the house, she has treats but generally she is really good. The issue is, her diet is pretty healthy, she loves vegetables and that is not a problem, her favourite vegetables are sprouts!! But she can eat in HUGE quantities for such a small person!! She can eat more than me, I dish her up a normal portion but she is always hungry, she would graze all day and still have huge meals. There is never a time she isnt hungry!! This wouldnt be a problem if she wasnt putting weight on. She's not hugely overweightor anything but she's getting squishy around the edges, which I adore but if she keeps eating at this rate it will get out of control! x