While some trainers are locked into one fitness approach they know and love, Bob Harper, co-host of NBC's The Biggest Loser and author of The Skinny Rules, enthusiastically embraces new trends such as CrossFit, kettlebells, and heavy ropes and explains how to make them work for you. Follow Harper on Twitter or Facebook (his accounts are linked) and you'll get great health advice, motivational tips, and pics of his adorable dog Karl that will instantly boost your mood (They do box jumps together!).
Why you'll love him: "Go to bed slightly hungry. Denied fuel for more than five hours, your body will start burning its own fat and sugar. Make a point not to eat after dinner and you’ll be burning fat while you’re sleeping." Even when he's tough, you know it's for your own good!