In a recent interview about juice cleanses, Tracy Anderson said: "They're horrific for people's health. They crash people's metabolic rate." She went on to say that FDA-mandated pasteurization makes the typical organic juice "give you Type 2 diabetes potentially. If you're going to drink non-organic green juice, you might as well eat a Twinkie."

Are juice cleanses really as bad for you as desserts are?

Juicing sinks your metabolism. The typical juice cleanse involves consuming nothing for days except organic juice, which is really low in calories and has nearly no protein. According to Janet Lee, R.D., a nutritionist based in Philadelphia, living off these juices puts your body in starvation mode and slows fat burning. "It also causes your body to consume muscle mass for fuel, and that further decreases your metabolism."she says.

What about claims that pasteurizing organic juice turns it into a diabetes-delivery system? It's apparently not backed up by science. "Pasteurization is a process that uses high heat to kill bacteria and lower the risk of food-borne microbes from making you sick," says Lee. "It's a great thing, and there's no proof that it strips a food of its nutrients or makes it less healthy. And though juice has high amounts of natural sugar, "no one will get diabetes because they went on a juice cleanse."

But Lee agrees with Anderson: Juice cleanses are not a smart way to dissolve fat. "You might lose weight quickly, but it comes right back when you go back to eating regular meals," she says.