Not every year is defined by a big-name diet or fitness trend – think Atkins or the Thighmaster. That's a good thing. Such popular quick fixes so often turn out to be just fads. The science that really defines how we think about health and fitness requires more time and consideration. Major studies confirm our hunches (that nuts are good for us), shed light on hidden health hazards (oral sex and brown rice), and give us better ways to get fit and look good, such as high-intensity interval training regimens, which are on the rise now. Here are the nine best health and fitness trends we spotted this year – the ones we think will last.