You ran an extra half-mile today and want to reward yourself with one of your favorite junk foods. You're craving pizza or ice cream or candy. You know none of these foods are good for you, but do you know which ones would do the most damage to your diet? Keep reading for the best and worst junk foods of all time.

The Worst

  • Pizza: It's not just the hundreds of calories in pizza that make it unhealthy; the sodium content is through the roof, too. Consider this: The National Academy of Sciences' Institute of Medicine says adults should get between 1,500 and 2,400 mg of sodium a day. Just two slices of frozen DiGiorno pepperoni pizza contain 2,020 mg.
  • Soda: A study by the University of Cincinnati found that consuming fructose (a key ingredient in soda) changes the body's metabolism in a way that makes it easier to store fat. Even if the total amount of calories consumed is the same, someone who takes in more calories from soda will be more likely to gain weight, the researchers concluded.
  • Twinkies: How bad can this "classic" junk food really be? After all, it's been around since 1930, and Hostess says it sells 500 million of them every year. But the iconic food is still bad for you. Many of the 39 ingredients are used to replace dairy products to keep Twinkies fresh longer. Cellulose gum, for example, is used to keep the middle creamy and smooth. And don't even think about eating it deep-fried: That will triple its caloric content.
  • French fries: Where to begin? The 8 grams of trans fats in a large order at McDonald's? Or the 480 mg of sodium in the Wendy's fries? Or the 600 calories in a king size at Burger King? That doesn't include dipping them in two packets of ketchup-which tacks on another 20 calories and more than 200 mg of sodium.
  • Milkshakes: Creamy, delicious milkshakes taste great, but they're oh-so-bad for you. Most milkshakes contain hundreds of calories and 25 to 40 grams of fat. Plus, there's a long list of artificial ingredients that go into flavoring most milkshakes. In Fast Food Nation, Eric Schlosser lists the 49 ingredients that create a strawberry flavor; most of them have names like "benzyl isobutyrate" or "4-methylacetophenone."

The Best

  • Dark chocolate with almonds: Dark chocolate contains more antioxidants than even red wine. Almonds also boost the antioxidant levels of this snack because they contain the best kind of vitamin E for your body.
  • Tortilla chips and salsa: Have some baked Tostitos and salsa for a snack that's packed with flavor, but not with calories. Even if you eat two full servings, you'll take in less than 300 total calories.
  • Gummy bears: You probably remember these candies best from your childhood, but it's the perfect mindless munching treat. Fat-free and low in sodium, a serving of gummy bears also has less than 100 calories.
  • Beef jerky: This food is high in protein and low in saturated fat, making it a good snack between meals--just watch out for additives like nitrates and MSG. Better yet, avoid these artificial preservatives altogether by eating organic jerky.
  • String cheese: Easy and fun, grabbing one of these cheese sticks will help you get the recommended daily amount of calcium in your diet. In addition, the prepackaged size will help control your portion. Concerned about the sodium? Try soaking it in water for a minute before eating.