Microwave popcorn might be an on-the-go dieter's best friend. It's a convenient, sometimes lower-calorie salty snack option. It's a whole grain, and it offers plenty of fiber per serving, which fills you up. And it's certainly better than the movie theater's fat- and salt-laden offerings. But microwave popcorn is far from easy on your health. No matter how convenient that bag of microwave popcorn appears, there's a good chance it's loaded with fat, calories, and sodium. Four cups of Orville Redenbacher's Ultimate Butter popcorn (popped) has 160 calories, 11 grams of fat and 440 milligrams of sodium. Even the light version has 110 calories, 5 grams of fat and 360 milligrams of sodium. Worse than that is the presence of trans fats in many microwave popcorn brands on the market. The butter-flavored bags are the worst culprits, weighing in with as much as 7 grams of trans fat per bag! Microwave popcorn seems to pose a more ominous health threat, however.