Now Weiner has also written an e-book, The Ice Diet. It's free—part of his stated wish "not to get lumped in with the counter-productive fad diet (snake oil) promoters."

As a practicing gastroenterologist, Weiner says he regularly avoids micromanaging food selection. He manages obesity as an illness and diets as part of a holistic approach to good eating. "I would usually cringe when patients brought up the weight loss diet of the day, usually some poorly documented and improbable strategy. I never thought I would be actively promoting and discussing weight loss diets."

But now he is, so, what's to know about using Weiner's ice diet?

When you eat a significant amount of ice, your body burns energy to melt it. Eating ice should, by the logic of this diet, also provide some level of satiety, if only so far as it physically fills space in the stomach and mouth.

By Weiner's calculations, ingesting one liter of ice would burn about 160 calories, which is the energy equivalent of running one mile. So you get to eat and burn calories. Ever since the death of upward mobility, that has been The American Dream.

What's more, it's probably safe. "Ingesting ice at this level should not have any obvious adverse consequence in otherwise healthy persons," Weiner, who trained at Johns Hopkins, writes. "For the vast majority of adults and children, there does not appear to be any contraindication to the use of the Ice Diet right now."

One piece of evidence for the safety of ingesting substantial amounts of ice, Weiner notes, comes from the case study of the 32-ounce 7/11 Slurpee, from which he concludes, "The ingestion of one liter of ice per day appears to be generally safe."

At some point beyond that liter, too much ice can be a problem. In the case of one obese person who attempted to eat seven quarts of ice per day, Weiner says, "Not surprisingly, this person suffered an uncomfortable feeling of coldness." In his professional opinion, that much ice per day would, for most people, be a "toxic dose." He recommends avoiding eating much more than the Slurpee-tested one liter of ice daily, "to avoid hypothermia or unusual cooling of the body. ... Some organs do not work optimally when the body temperature drops too much."

"For children using the Ice Diet, the amount of ice ingested should be monitored and related to their body weight and ability to report any problems that they might be having by ingesting ice." Do not put ice into the mouths of children who can't tell you if their brain has frozen.

For much the same reasons, use caution when using the ice diet during cold weather, Wiener says. Don't eat ice on the ski slopes or while shoveling the walkway.

Don't eat ice when you're too hot, either. After running, for example, the body actually exerts energy through the active effort of dissipating excess heat that builds up during exercise. "If one were to ingest large amounts of ice as one was cooling off from exercise," The Ice Diet warns, "some of the heat that had been generated by the exercise would be neutralized by the coolness of the ice, minimizing some of the energy burning benefits of the exercise."