Scientists recently made a discovery they think could put an end to obesity: A substance containing olive oil that can help keep you full for 12 hours. Sure, it's not available yet, but this isn't exactly rocket science -- you can find foods that have a similar effect on your hunger pangs at the local grocery store. The key is choosing foods that will fill you up. Here are some items to try:

• Fiber is filling because it takes longer to digest. Go for things like whole grains and legumes to get your fiber fill.
• Protein is the best fill-you-up food there is -- just make sure it's of the lean variety. Think low-fat cheese, lean poultry or fish.
• Wet foods are more filling than dry ones simply because they trick the brain into thinking they have more calories. Choose oatmeal over a cereal bar, and start with vegetable soup over a bread basket.
• Fill up on foods that have a low energy density, like fruits and veggies. Think about it this way: For the same amount of calories, you could have one slice of pizza or five oranges. Which one is going to leave you full?
• Water. OK, water is not going to keep you satisfied for hours, but it can quiet minor hunger pangs if you drink enough of it. Trust me -- if you get yourself hydrated, you'll notice you're eating less.

As for foods that won't fill you up? Whether real or fake, sweet things top the list -- even diet soda can leave you feeling hungry.