For those of us who generally don't like food, consider it an annoyance, and yearn for a way to avoid eating it, Soylent sounds immensely promising. But is it safe?
Surprisingly, the answer from nutrition experts seems to be, "Yeah, probably." Jay Mirtallo is a professor of pharmacy at Ohio State and the immediate past president of American Society for Parental Enteral Nutrition, which focuses on the science and practice of providing food to patients through both intravenous injections and feeding tubes. His main concern with Rhinehart's plan is that he's making the concoction himself, rather than buying it from reputable suppliers.
"He basically made medical food," Mirtallo says. "If he wanted to switch to a liquid diet, those are already available."
"They’re very complex products, in terms of making sure you get them in a form that’s palatable but that stays in a form that’s bioavailable to the body," Mirtallo says. "Some of the products are very difficult to get into a liquid form and may lose their potency when they do that, or could interact with other substances that keep them from being absorbed completely."
That's why it's important to use products from real companies that have to obey FDA labeling regulations. There are real downsides to trying this stuff at home.
That said, medical foods have been used to keep patients going for many years, and they basically work. The biggest risks have to do with the means of administration. Having a needle in your arms for extended periods of time isn't great for your arteries or general circulatory system, for example.
"We really try to minimize how much nutrition somebody gets intravenously," Dr. Andrew T. Chan, a gastroenterologist at Massachusetts General Hospital, says. "As much as we can, we want people to use their gut, because using your gut and your bowels is the best way to maintain nutritional balance and the best way to maintain health."
There are plenty of possible complications with feeding tubes, ranging from the risk of food going into your trachea and then to your lungs to the risk of acids leaking out if an incision has been made to the stomach. That's why some predecessors of Rhinehart's approach, like a feeding-tube based diet that took off in South Florida last year, have generally met with derision from medical professionals.
But if you're just drinking the stuff, none of those are concerns. "The liquid still keeps the gastrointestinal secretions stimulated, and so gastrointestinal function is normal," Mirtallo says. "There used to be trouble maintaining normal bowel movements, but now that they have formulas that have fiber, so that gets normalized as well." Indeed, many nutrient bars you see in convenience stores use the same techniques as medical food for jamming in nutrients. Chan notes that there's no evidence that the consistency of food, be it liquid or diet, affects health or nutrition.
I asked Mirtallo if I could live a healthy life just drinking medical food from here on out. "You can completely," he says. "But I don't know why you'd want to. There are so many social aspects to food in what we do."
One potential downside is cost. Rhinehart claims that he only spends $154.82 a month on Soylent. By contrast, a case of 24 eight-ounce cans of Jevity 1.5cal, a high caloric density product Abbott sells for feeding tube patients, costs $57 from Abbott's Web store. As each can has 355 calories in it, you'd need six cans a day to top the 2,000 calorie a day mark used in FDA nutrition data. So a 24-pack would last you about four days. That works out to 7-8 packs a month, which could cost up to $456.
Rhinehart is currently looking for volunteers to try Soylent and then conduct blood tests — and, full disclosure, I've offered to try it — but if you're serious about never eating regular food again, real medical food from Abbott or Nestlé is the way to go.