are there any natural appetite suppressants that work?  

I think you may have need to reconsider the problem. Most experts agree that eating more, rather than less, of the right foods actually increases your basal metabolism (the amount of calories you burn when not doing anything). Check out the Abs Diet by David Zincenko (?) for a good explanation of this. He also has extremely useful and eye-opening information about the right foods to eat and those to avoid. When I first tried his method, I thought I'd be sick from eating so much - but I lost a great deal of bodyfat as a result and have kept if off. I still follow his habits and I'm at my ideal weight. Best of luck to you!

I would not recommend appetite suppressants to control your hunger. If you are seriously eating a whole bag of grapes at once then you probably not noticing how full you are until you are beyond stuffed. Try pausing just for one minute to see how full you are or how hungry you really are.

I have found that I do a lot of mindless eating where I will eat regardless of true hunger. This is the reason I find for me that I gain weight as I keep giving my body fuel even when its not hungry.

I have recently discovered a good book on the subject of alternatives to dieting. If you are interested to know more then please take a look at the website www.beyondchocolate.co.uk

That will tell you more about the approach and there is also a link from there to amazon for the book.