How do those human regurgitators like that Stevie Starr guy from Sweden do it? How are they able to swall billiard balls and bring them back up, pop balloons with nails in their stomachs, swallow fish and spit them back out, and swallow sugar and bring it out dry? I promise I'll never try any of this. . I'd just like to know how they do it (if they do it at all).
First off, I can find no reference anywhere to Stevie Starr having done his act while under medical examination. This means that anything I say is pure speculation, and removes some credibility from his act. If he weren't doing something tricky, having an MD closely observe the process and explain it would only help his act.
That said, I do believe that he really is "swallowing" these items. (A video of his show can be found at http://www.chizang.net/alex/misc/stevie_starr.wmv ). The only website I can find that offers any explanation is http://www.andrewferguson.net/2005/02/23/stevie-starr-the-regurgitator/ , which suggests that perhaps Stevie Starr has amazing control of the various sphincters in his esophogus/stomach. When it comes down to it, Stevie Starr would have to have amazing control over all of the muscles in that entire area of his body (not to mention a complete lack of gag-reflex).
Whatever the case may be, the process obviously causes great discomfort. Being a showman, Stevie Starr would never make all of the weird noises and actions if they were not necessary. Yes, like any showman, he exagerates, but he is not comfortable. You will also notice that he always grabs a drink of water imediately after each process.
The one slight explanation that I can offer you is about the sugar coming up dry. If you watch closely, he only regurgitates a small percentage of the sugar that he swallows (he catches it in a different container so that you won't notice). If you have ever measured sugar in a wet measuring cup, you will understand what is happening. The sugar that gets wet sticks to the side of the measuring cup, so that when you pour it out only dry sugar comes. Stevie Starr must "hold" this sugar some place that the water he drinks cannot reach, so that when he regurgitates the sugar a decent ammount can still come out dry.
Finally, it appears as if Stevie "The Human Regurgitator" Starr is the only person capable of such feats. So, don't try this at home.