The 10 Craziest Health Trends of the Past 40 Years

The Idea: Spot reduction is possible—you just needed the right piece of equipment.

The Problem: Ask any exercise expert and they'll tell you spot reduction is a myth. Devices that claim to master your thighs or zap your abs into a 6-pack may make the muscles in that area stronger, but they don't get rid of the layer of fat sitting on top of them. "If you don't remove that fat, you get strong abs and thighs that you can't actually see," Gaesser says. "To lose weight and make those muscles visible, you have to elevate your metabolic rate over a long period of time."

The Lesson: Body-part specific gadgets alone won't get you results. Combine strength training with cardio and then you're getting somewhere.