When he became determined to lose weight, Dr. Brian Weiner decided to change his eating and exercise regimes. "One of the first changes I made," explains Weiner, a gastroenterologist in New Jersey and assistant professor at Robert Wood Johnson Medical School, "was to give up my beloved ice cream."
Aiming for something lighter, Weiner replaced it with Italian ices. The cups at his supermarket listed their calorie content as 100—calculated by multiplying 25 grams of carbohydrate by four calories per gram. "One evening, in a burst of insight," Weiner writes, "I realized that this calculation was incorrect. The manufacturer of the ices did not calculate the energy required to melt the ice, and did not deduct this from the calorie calculation." By Weiner's math, he was actually only consuming 72 calories, or "icals," his term for the net caloric content of ice-containing foods after considering the calories that the body burns to produce the thermal energy that melts the ice.
Weiner reviewed the medical literature. "I found that no one has clearly identified this oversight," he writes. "I could not locate references to considerations of the implications of the energy content of ice as food."
After discussing the issue in detail with his son, an engineering student at Rutgers who vetted his father's calculations, Weiner submitted his story as a letter to editors of the widely-read medical journal Annals of Internal Medicine. They published it. In the article, Weiner said the idea could be of real importance to people trying to lose weight. It's meant as a supplement to overall diet and lifestyle that go into maintaing a healthy physical form. "While eating ice, you are serving two purposes," Weiner explains, "you are burning calories and not eating positive-calorie foods."
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."
Physics writer Andrew Jones offers more skeptical calculations as to the caloric benefits of the ice diet, determining that eating a kilogram of ice would burn 117 calories. "To reach the 3,500 calories required to lose a pound of weight, it would be necessary to consume about 30 kilograms [66 pounds] of ice," Jones writes. "Not exactly the most efficient diet plan." That means, if you ate a liter of ice every day, you would lose about a pound of weight every month, all other things in life being equal. That's not bad. And all other things wouldn't be equal. Everything in your life would be different because you would be eating a liter of ice every day.
Also, of course, chewing ice can cause dental problems. Beyond full-blown cracking of teeth, the practice can damage the gums and enamel or injure the temporomandibular joint. To avoid dental damage, Weiner writes, "I would recommend that ice be allowed to melt in your mouth, as with ice pops, or consumed with the texture of shaved ice, as in the 7/11 Slurpee or the frozen margarita."
Except don't actually drink a liter of Slurpee every day because that sugar load would more than undermine this entire venture, and drinking a daily liter of margarita is this whole other thing. Weiner recommends making the process less onerous by making your own ice-pops using calorie free liquids instead of sugary concoctions or fruit juices. "For those with a larger budget, the Jimmy Buffett Margaritaville machine shaves ice into a very fine slurry, which can be consumed as-is or flavored with artificially flavored products."
It's that easy and, assuming the artificial flavoring you use is totally safe, you're good to go. You don't even have to worry about this fad diet becoming uncool. If anyone tells you it's uncool, you can just cross your arms and say, "It's objectively the coolest diet around in terms of temperature." Pass the slurry.