Stick to natural foods as much as possible and use protein shakes when you need something portable.  Other options include an apple with peanut butter, a handful of mixed nuts, cheese sticks, cottage cheese, or Greek yogurt (much creamier than US versions – I like a brand called Fage).  If you are on-the-go, you may have to do a little planning to make sure you’ve got these healthy snacks on hand. But the time you put in will be paid back through increased fat burn!