Stores deliberatetely stock tempting treats in your line of sight. It's so easy to sabotage yourself by buying and eating based on impulse. When you're tempted to make an unhealthy, on the spot purchase, choose to put it back. Then put the money you would have spent in a reward or goal fund.
You may be very surprised at how much you spend here and there on impulse buys you don't need, and often times, don't really want.