Expert's take: "Yo-yo dieting can wreak emotional havoc," says Blake. "It takes years of effort to lose weight; why keep going through that work? Having a friend to cajole you to get to the gym is a great idea. You don't want to blow them off, and you always feel better afterward. As for organic foods, there's nothing magic about them. They can be expensive, and they won't make or break your weight loss efforts. The real magic foods are fruits and veggies, organic or not -- they outsmart your stomach by filling you up on fewer calories."