Like the Master Cleanse, juice fasting is a type of dieting which should be avoided.

This is not, however, how juice has gotten a bad rap. Juice is thought to contribute to the increase in childhood obesity.

That is, until now.

You can give your kid back his juice box, thanks to a new study from Baylor College of Medicine that found 100 percent fruit juice actually doesn’t cause weight gain in preschoolers.

“One hundred percent fruit juice provides valuable nutrients such as vitamin C, potassium, and magnesium that aren’t found in other fruit drinks,” says Theresa Nicklas, Ph.D., the lead researcher on the study.

Read the label and make sure it’s really 100 percent fruit juice — otherwise, it’s not much better for your kid than candy, she says. Aim for no more than six ounces of juice per day.

And, to give your child the most nutrients, opt for orange juice: It contains twice as much magnesium and potassium and three times as much folate as apple or grape juice. Let it pour! [source: Redbook]