[anigbrowl]

That's something you really need to do your own research on, it's a big topic. Start by looking up 'complex carbohydrates' and consider that while they are made up of basic sugars, in nature the breakdown of those complex carbs would be done mostly in the gut rather than through refinement in a sugar plant. A pediatrician friend of mine doesn't even believe in consuming juice, because she considers the body is better able to regulate its sugar intake by processing the fruit and also using the non-nutritious bulk fiber of the fruit to regulate the amount consumed. This is her hunch rather than being proved through exhaustive research, but it seems like a fairly well-informed hunch.

[DanBC]

A glass of juice is a lot of sugar. One serving size of fruit is much smaller, and would give very much less juice. It's very easy to drink a lot of sugar if you're drinking undiluted juice.

Dietitians in the UK recommend that people are cautious with juices and smoothies because of the amount of sugar, and they recommend that people just eat the fruit and drink water. Especially for children, the high sugar and acid is tricky for teeth.

(I agree that the hunch seems reasonable. But then, those are the things that need research, to combat my biases.)

[acgourley]

Dr. Robert Lustig agrees, from http://www.kqed.org/a/forum/R201301280900

"Processed food is fiberless food. That's basically what it comes down to. Processed food means that you've got to take the fiber out for shelf-life. And there are two kinds of fiber. There's soluble fiber: which is the kind of stuff that holds jelly together, and pectins, and things like that. And then there's the insoluble fiber: the stringy stuff, like, you know, cellulose, like what you see in celery. You need both. What I describe in the book is like it's kind of like your hair-catcher in your bathtub drain. Um, you have this plastic lattice work with holes in it. So, if you take a shower and the hair is coming down, it blocks up the holes, but only if the hair catcher is there. So, imagine that the cellulose is the hair-catcher, and imagine the hair is the soluble fiber, blocking up the little holes. When they're both there, it forms a barrier on the inside of your intestine.

You actually can see it during electron microscopy, that it's a secondary barrier that reduces the rate of absorption of nutrients from the gut, into the bloodstream. And what that does is that it actually keeps the liver safe, because it reduces the rate at which the liver has to metabolize, the stuff. And if you overload the liver, what it does is it has no choice but to turn extra energy into liver fat. And that's what drives this whole process. Is the process of liver fat accumulation, and the thing that does that the worst is sugar, especially when it's not teamed up with fiber.""