Update: Since publication of this article, former Soylent supplier TerraVia has severed its relationship with Soylent, citing the company's unsupported claim that TerraVia's algae ingredient was the cause of Soylent consumers' gastrointestinal woes.  

It’s hard to stomach one of Soylent’s latest developments. “Food Bars”—the start-up’s most recent unveiling in its line of tasteless, beige, futuristic foodstuffs designed to replace meals and ultimately render them obsolete—have caused hundreds of consumers to experience nausea, intensive bouts of vomiting and diarrhea, and in some cases, hospitalization. Now, its meal-replacement powders are making people sick, too. Since the Los Angeles–based company’s 2013 inception, Soylent has gained upward of $22 million in funding, a cult following among its target audience of Silicon Valley tech workers, and infamy. The latter is due largely to Soylent founder and CEO Rob Rhinehart’s curious claims that actual food is “glaringly inefficient,” due to the time and energy required to prepare and consume it. Of course, what’s arguably less energy-effective is time spent vomiting.

The first health issues were reported September 7, shortly after Food Bars’ release. Soylent, which has since discontinued the bars and issued an online advisory warning that consumers discard any remaining bars, is still struggling to determine the source of the gastrointestinal mayhem. As of November 7, it suspects the fiasco may have something to do with the Food Bars’ algal flour. Soylent's supplier, TerraVia Holdings, argues that Soylent products contain several potentially discomforting irritants, and that its algal products have not caused problems for others among their many clients.

In any case, the past two months have raised plenty of questions about diets based around soy protein isolate, algal oil, tapioca-derived starch, and other compounds and derivatives best described as distant cousins of actual food. Soylent claims to be an environmental paragon in that it's reducing food waste and energy expenditure, but has raised eyebrows for its outspoken embrace of GMOs and for what some perceive as a resentment of food.

Rhinehart, a self-described proponent of “extreme sustainability” (read about his attempt to live “without the luxury of the alternating current” via his personal blog), describes kitchens as “the greediest consumers of power, water, and labor.” Over on the Soylent blog, Rhinehart claims that his product “endeavors to improve the capability and efficiency of our industry through research and development, toward a future where food is abundant and its production is transparent.” He goes on to write that because Soylent’s ingredients are vegan, with half their fat stemming from “farm-free algae sources,” the products carry the potential to reduce the ecological impact of food production, thus “signifying a major step towards a future of abundance, a world where optimal nutrition is the new normal.”

Even after last year’s unveiling of preprepared, individual meal-replacement shakes (“Soylent 2.0”) raised packaging concerns among some users, Rhinehart argued, “1,600 calories worth of Soylent 2.0 still produces much less waste than 1,600 calories of regular food, on average.” Indeed, Soylent would have its many loyal fans believe that even the most local farmers' market’s healthiest selection of fruits and vegetables is representative of a wasteful culture.

Keep in mind, Rhinehart, 28, started Soylent without any background in biology, environmental science, nutrition, or even food preparation. The start-up is rooted in his somewhat unhinged vision of a day when food—and thus nutrition and hunger—could be made irrelevant, when food “could just be art.” Also remember that Soylent products are now causing consumers’ bodies to hit the eject button. So, there’s one reason to take Soylent’s “extremely sustainable” claims with a grain of salt.

For another, industrial soybean agriculture—the source of the eponymous products’ main ingredient—often leads to soil degradation and relies on chemical fertilizer and pesticides, and in Brazil and Indonesia, encroaches on fragile ecosystems such as rainforests and savannas, thus contributing to deforestation and greenhouse gas emissions. Dr. Keith Kantor, a nutritionist, researcher, and Consumer’s Health Digest panelist, adds that soy also contributes to GI woes. “Especially when it comes to GMO soybeans, its protease inhibitors suppress key enzymes that help us digest protein.”

But Kantor notes that soy also contains isoflavins, which affect hormone balance. “They contain a lot of estrogen,” he explains. “And today, 93 percent of soy crops grown in the U.S. are genetically modified, with a lot of glyphosphate, too, which throws off your insulin mechanism, affecting the body’s ability to process sugar.” Adds women’s wellness advocate Kim Castle, “Soy protein isolate, a key ingredient in Soylent, is made from defatted soybean flakes that have been washed in alcohol or water to remove sugars and dietary fiber, thus stripping the pure soybean of its nutrients.” More worrisome, Castle says, soy protein isolate has a tendency to absorb properties of the container it is stored in. “This is how aluminum, which can affect the central nervous system, leaches into food.”

Soylent did not respond to requests for comment.

Kantor further points out that Soylent contains plenty of corn starch, which also relies on heavy industrial farming and heavy processing, and is known for its high glycemic index. Then there’s Soylent’s heavy reliance on fructose—“known to be hard on your liver function,” Kantor says—as well as artificial sweeteners. Castle adds that Soylent consumers’ health troubles could very well have something to do with its primary artificial sweetener, isomaltulose. “Most sugar substitutes ending in ulose can cause gastric issues.” Kantor adds that Soylent is “chock-full” of synthetics in general. “Its synthetic vitamin A has pyrodextrin, which is hard to digest, as well as sulphates and phosphates, which can increase cardiovascular risk.”

Soylent’s ingredient complications don’t end there. Last year, advocacy group As You Sow filed a notice of intent to bring legal action against Soylent, alleging violation of California’s Safe Drinking Water and Toxic Enforcement Act. The problem? Soylent powders evidenced high levels of heavy metals, namely, lead and cadmium. As You Sow president Danielle Fugere says chronic exposure can cause kidney, liver, and bone damage, as well as developmental problems, male reproductive toxicity, and permanent neurological impairment in children. “Currently science doesn’t know what level of lead is safe,” Fugere says, “but we do know that lead and cadmium both accumulate in the body over time.” As You Sow tested the powders out of a concern that the food supply, in general, is becoming more polluted with heavy metals—thanks to pesticides, herbicides, and food production increasingly taking place near industrial facilities such as coal-based power plants. “Highly processed protein powders specifically tend to be high in heavy metals,” Fugere says.

She says As You Sow’s legal notice caused a “storm of interest” among Soylent users, and that it apparently prodded the company into reformulating. “We just tested their most recent powder products, and while the lead is still slightly elevated above ideal levels, cadmium is now below,” she says. “We’re trying to test Soylent’s shake forms, but it’s harder to get the right detection level with liquids.”

It would seem that Soylent, regardless of what these tests find, has plenty of reformulating cut out for itself. But the company, which plans to reintroduce the Food Bar, sans algal flour, in the first quarter of 2017, seems confident that they can resolve its issues. The company announced in a recent blog post, “We are going to look into this further, and share our findings with the FDA so they can do their own evaluation.”

Kantor says the intrinsic connection between food systems and planetary health is ultimately undeniable. “It takes a lot more energy to create artificial ingredients than it does to make, or source, actual food,” he says.