On the rare occasion you have to grab a snack from the closest vending machine, these guidelines can help you choose more nutritional options:
Consider baked or reduced-fat snacks. The baked versions are almost always lower in fat, and the reduced-fat or light ones have at least 25% less fat than the originals. However, those "lighter" options may be only marginally lower in calories. And some have more sodium.
Check sodium and sugar. In general, chips have the least salt; pretzels have the most. Flavored varieties of any snack tend to have significantly more sodium than regular versions. Reduced-fat or otherwise "improved" products often add extra salt or sugar.
Be careful with "natural." Unlike "organic," the claim "natural" is not defined by the Food and Drug Administration. So check the ingredients list when possible.
Find value-added options. Snacks that include fiber, protein, or both are likely to keep you fuller longer than mere carbohydrates. Plus, they offer some nutritional benefits. Nuts or soy snacks pack plenty of protein and fiber. Treats that list a whole grain (such as whole wheat) or bran as the first ingredient should provide at least 2 grams of fiber per serving.