As long as this popular crunchy treat isn't doused in movie-theater butter, it makes an excellent weight-loss snack. Not only is popcorn high in fiber, it even delivers some protein. A 1-ounce serving of air-popped corn (about 3½ cups) has 4 grams of fiber, almost 4 grams of protein and clocks in at 110 calories. This combination makes it a snack with staying power. Popcorn is filled with air, so you get a pretty large portion without a lot of calories. You can eat 3 whole cups of popcorn for only 100 calories.
For a 2,000-calorie daily diet, aim for 2½ cups of vegetables and 2 cups of fruit a day. If you consume more calories, aim for more produce; if you consume fewer calories, you can eat less. Include green, orange, red, blue/purple, and yellow vegetables and fruits. In addition to the fiber, the nutrients and phytochemicals in these foods may help protect against certain types of cancer and other diseases. Legumes, rich in fiber, can count as vegetables (though they have more calories than most vegetables). For more fiber, choose whole fruits over juice.