Vending Machines

Best Picks: A small bag of plain pretzels — not honey-mustard or any other flavor, which can add fat. “Pretzels are a satisfying, low-fat crunch without any trans fats or added sugar, and the single-serving-size bag means you get built-in portion control,” says Keri Glassman, a registered dietitian in New York City and the author of The Snack Factor Diet (Crown, $20, www.amazon.com). A close second is a small bag of peanuts or almonds, which is packed with protein that will fill you up, says Sarah Krieger, a registered dietitian in St. Petersburg, Florida. And the petite package prevents mindless eating from a big jar, which can be a danger at home.

Another Good Option: Whole-wheat crackers with peanut butter. While these little sandwiches can be higher in fat or calories than a serving of pretzels, “they have good fat and a little fiber,” says Krieger, which will keep you fuller longer.

Worst Picks: Potato chips, corn chips, and tortilla chips. They’ll give you greasy fingers, but that’s not the worst of it. Most snack chips are low in protein and fiber, and some are high in the two worst kinds of fat: saturated fat and trans fats.