I'm not going to debate whether I think the study from Dr. Oz is legitimate or not, as it probably is pretty accurate. I think Juice is vastly misunderstood by 99.9% of the population.
Juice is not a health food! Kids should not be drinking juice everyday, throughout the day. The juice from fruit is actually the BAD part of the fruit; it's the fruit minus all the fiber, and micronutrients. It's pure fructose.
Only your liver can metabolize fructose so let me take you on a journey through your liver when you consume juice. Your body first has to give up phosphates to start metabolizing the fructose making the waste product Uric Acid (causes gout) which blocks the enzymes from making Nitric Oxide (keeps your blood pressure low), when you can't make nitric oxide your blood pressure goes up. Nova Lipogenesis gets activated and now you get fat. When you consume fructose you are consuming fat. Fructose increases inflammation in the liver by initiating an enzyme that is truly and appropriately named “Junk 1". Free fatty acids form and populate muscles. Some fat will not make it out of your liver, and you wind up with fatty liver, Non-Alcoholic Liver Disease.
Your pancreas starts working harder generating more insulin because your liver becomes insulin resistant. The more insulin your pancreas makes the higher your blood pressure goes and it also generates more fat. The higher your insulin goes your brain can't see it's leptin (the thing that tells your brain you are full) and you keep consuming calories because your body thinks it's starving.
Is it any wonder why the obesity epidemic is growing fastest in 2-5 year olds? That young children are being diagnosed with diabetes, high blood pressure, gout, fatty liver disease, heart disease, insulin resistance, dyslipidemia, and high cholesterol? ALL of these things happen with chronic fructose exposure.
One thing you can do as a parent to help your kid's avoid pain & illness is to limit all beverage consumption to plain water, and milk. It's probably the single most important thing you can do. Offer fresh fruits and veggies. Fructose is absorbed differently if consumed in its natural whole fruit form as the fiber attached helps slow absorption.