A hundred years ago, food was simple. People didn't worry about trans fats in their cheese crackers or artificial colors in their fruit snacks. They didn't have to—they were eating real cheese and real fruit. And food companies used to focus more on making food than on enticing people to buy it. That's why supermarkets are so daunting today: It's easy to make a false move, even when you're trying to eat healthy.

Researchers discover how body's good fat can burn other fat.