Sounds like a great science fair project title... but I'm very curious. I once read on Dr. Eades' nutrition blog that even though artificial sweeteners are noncaloric and don't actually contain any sugar, the body still to a certain extent treats them the same way: it tastes sweet, it anticipates sugar, and pumps up insulin production to compensate for what it anticipates is coming. Sugar never does come, though, and the increased insulin leads to hypoglycemia in the short term and contributes to insulin resistance in the long. I don't remember if this was put out as fact backed by a study or just as speculative theory, though.

So this makes me wonder: we all talk about how great it is to head into our dreams and eat whatever we want there because it won't do anything bad to our health, but maybe this isn't actually true. If we eat loads of calories in our dreams, well... obviously we won't get obese from those, they're imaginary, but isn't taste just taste, whether in real life or in a dream state, and couldn't we expect the body to react to taste in predictable ways regardless of where the stimulus is coming from? Could it be that when we eat a dream donut, our bodies go through some of the motions of digesting a donut all the same? And some of those motions are bad for you (insulin release, etc) regardless of whether or not they're put to any use (digesting the donut vs. nothing).

Does anybody have any anecdotes or obscure lucid research to back up this idea? I'd love to see LaBerge or somone similar try this by taking blood glucose levels from lucid dreamers before and after eating something really sinful.