Or one of those pandora style (the real ones are too expensive) but a bracelet you can add a new bead on for each 7lb - that's what I've done then when I'm finding things difficult I just fiddle with the beads I've added to remind me why I'm saying no to that extra beer, or glass of wine, bar of chocolate
I am going to think about why I want to be healthier and slimmer and list them. What my rewards will be and list them too.
I have kept that chocolate, just so next time I feel stressed and reach for the rubbish I can remind myself it is not what I need or want!