So you're trying to take some pounds off, but you like to snack every once in a while. Unfortunately, once you open a big bag or box of, say, chips or cookies, pretty soon you’ve eaten the entire thing.

So here's the question: How can you keep your appetite (and your willpower) under control?

First, get more protein—it keeps you feeling fuller than any other nutrient. A 2014 University of Missouri study compared protein- and fat-rich snacks and found that even when the number of calories in all the snacks were the same, subjects who noshed on protein stayed fuller longer and ate less at the next meal. 

Another strategy is portion control, and there’s some very helpful news on that front. A 2015 study in the journal Appetite found that people who ate their snacks out of larger packages seriously overestimated the size of one “serving.” Translation: If you eat from a trough, you’ll pig out more.

So when you do snack, make sure it’s one of these 13 protein-packed snacks, and find a smart way to limit portions.