After four solid days eating nothing but Soylent, Saturday dawned. I awoke feeling about the same as I had the day before and the day before that. I didn't feel particularly incredible, but I didn't feel bad either. Coffee led to my morning Soylent, which was from yesterday's blue batch. I had plenty left to get me through the day—it looked like about half the pitcher remained.

I had a half-formed plan in my mind though. Perhaps, just perhaps, I could stretch this pitcher through to dinner. Because if I could make this bit of Soylent last all day, I'd have one full, unopened, shiny plastic pouch left. My friends and I were all supposed to gather at Matt's house for Labor Day, and rather than showing up with steak and hamburgers to grill—well, I could show up with Soylent. I could make all of them drink it. It would be a Very Soylent Labor Day.

The final countdown

As much as I'd like to have some grand crazy story to wrap up my final day of Soylenting, things were uneventful. My poo continued to look like a preschooler's art project, but that's more because of my dabbling with food coloring than anything the actual Soylent was doing. The gas pretty much disappeared. The chalkiness still got to me, but I started adding more and more water to my mug-sized servings, and that cut the chalk right out.

I didn't bleed out of all of my orifices, I didn't go into hyper- or hypoglycemic shock, and I didn't combust. I finished the pitcher for dinner, smacked my lips, and tossed all my Soylent implements into the dishwasher. Later that evening, I ate my first piece of food in five days: a banana. (It was late and I wasn't super hungry.)

Returning to solid food was not earth shattering. I didn't experience any kind of food-related tastegasm, and my jaws didn't ache with release from chewing. It was a banana. It tasted like banana and then I went to sleep.

On Sunday, I woke up and had my usual bowl of oat bran for breakfast, because when you're 35 you start having to eat things like oat bran because that's about when your body starts to betray you by getting old. It tasted fine.

Anticlimax

I kind of feel like I'm failing to deliver on the Soylent conclusion, because the narrative here doesn't really follow the traditional dramatic structure. There was rising action and a bit of falling action, but there was no real finale and no real denouement. Soylent worked and my body was able to handle it, initial overeating issues aside. I was able to take my normal 5k runs on it. Aside from adaptation gas, it didn't do weird things to me.

As the five days stretched on, I didn't feel bad. I didn't feel powerful longings for solid food. There was no overwhelming desire to cheat and buy a cheeseburger just to have something to sink my teeth into. In fact, I ate pretty lightly for most of Sunday too—rather than dump a whole bunch of crazy weekend food into my body, I gave it a day to adjust again. Switching back to "normal" food didn't bring with it any adaptation issues: no dizziness, no gas as my gut bacteria shifted gears again. Nothing.

From a weight loss perspective, the results don't seem statistically significant. I weighed myself at the same time and at the same point in my morning routine every day, and I lost 2.2 lbs (about 1 kg) over the five days. I've fluctuated more than that day-to-day from just eating normal food and exercising, though, so saying that I lost weight on Soylent is correct but not particularly meaningful. Based on my consumption rate, though, I'd figure that eating nothing but Soylent over several weeks would result in weight loss—of course, so would just about any nutritionally balanced food regime.

So, the experiment was a success, and I lived to tell the tale.

Feeding Rob Rhinehart some Ars commenter questions

Soylent creator Rob Rhinehart was kind enough to sit down and talk with me for a bit on the Ars Soylent experience. He answered some of the questions that came up in the comments over the past several days.

The one I most wanted him to elaborate on was on the why of it all. The comments on the past pieces in this series have been brimming with folks who can't (or won't, perhaps) see the point of Soylent. Whether it's because they love cooking too much, or they can't understand why someone would drink a nutrient slurry in place of food, some people were not at all on board.

"Soylent is supposed to be like an ultimate staple meal," began Rhinehart. "When you think about food, a lot of people immediately jump to the best aspects, which are great—eating for recreation, eating with people. This is an important part of life, and food is intimately tied with culture and tradition."

But not every meal is artisanal, fresh, and healthy; Soylent aims to fill in those gaps like a utility. "People will talk about beer and wine and gourmet coffee, but most of the time they're drinking water. By focusing on Soylent as a staple, fool-proof meal, this could do a lot more for health than some new recipe based on lettuce or something."

The name

The name itself, "Soylent," has drawn fire—but that's part of the reason why Rhinehart chose the name in the first place. "For food, a lot of people tend to react quickly and not give it a lot of analysis. Piquing curiosity is very important here, and giving the product some kind of flashy marketing name would kind of—people would miss it quickly. But the name 'Soylent' is really good for encouraging further discussion and thought. Clearly, I'm wanting someone to investigate it a little deeper if I'm calling it 'Soylent.' It doesn't seem very marketable!" The name serves several purposes—it catches the interest of geeks as almost an inside joke ("IT'S MADE OF PEOPLE!"), and it's remarkably sticky.

Hasn't this been done before?

This, though, leads into another topic that readers commented on repeatedly: Soylent's originality, or its perceived lack thereof. Meal replacement products aren't anything terribly new, and there are products both in the consumer space and also in the medical and healthcare space that can be substituted for solid food. Soylent is billing itself as a revolutionary product. Is it?

"From the consumer standpoint, those things aren't designed to be sustainable or really even that healthy," Rhinehart said, referring to things like Carnation Instant Breakfast and Slim Fast and other common off-the-shelf meal replacement shake-style drinks. "They're certainly not something you'd want to run your body off of—a lot of fructose, simple sugars, and by calorie it's really expensive. We've reached a point of calories-per-dollar and sustainability and nutrition where we're really trying to compete with groceries."

On the medical side, products like Jevity and Nestlé's entire line of liquid tube feeding products are in a separate league from Soylent. "We're not making any medical claims, other than it being safe for consumption," clarified Rhinehart. Additionally, from a perspective of calories per dollar, both the consumer and the medical liquid nutrition products are outside of what Rhinehart wants to target for Soylent. Rhinehart wants Soylent "to compete with rice and beans," he explained. "The routine meals that a lot of people are eating—that's what we want to compete with, especially if we can displace fast food."

Processed ingredients

The stigma carried by Soylent's processed ingredients also came up several times. Several readers twigged to the fact that Soylent is made of highly processed substances rather than an organic blend of things. "People who demonize food processing don't really understand what's going on there," clarified Rhinehart. "Food processing gives us fortified foods. It makes food cheaper. It allows people with allergies or dietary restrictions to eat better. It's a useful innovation, but it has been misused by many food companies—you can use it to make something that is very experiential but perhaps not very healthy, and unfortunately, that's what a lot of food companies design for. I think we can use this technology to make a very easy, nutritious type of food—cost effective and ubiquitous, and something that doesn't spoil."

Rhinehart continued, "It's important to realize that these nutrients, these chemicals—they're all the same. Whether your calcium comes from milk from a cow you own yourself, or from some industrial process, it's all the same for your body, as long as it's in a bioavailable form."

Taste, texture, testing

As Soylent barrels toward the market, there are still minor tweaks to the formula to be made, but the nutrition and taste components are mostly locked. The remaining adjustments are more to make Soylent manufacturable at scale than anything else. I brought up the chalkiness that I had such a hard time with, and Rhinehart acknowledged that as a "bug" with the formula. They are working around by altering the particle size of the rice protein.

However, no small subset of readers was concerned that Soylent would become widely available without an extensive test regime to validate Rhinehart's claims that it's a safe and healthy product; according to Rhinehart, none is necessary. Every one of the individual components in Soylent has already undergone FDA testing, which Rhinehart is quick to point out. "Of course something like this is safe for consumption. All of the ingredients are very well-vetted to be safe. Every one of them has been tested individually, and there are no conformational or chemical changes undergone by blending them together with water, and it's really unnecessary to test the mixture for, say, FDA GRAS testing." There are other tests to be done as part of the manufacturing process—ensuring the product is free of microbial contaminants or heavy metals for example—but that Soylent is safe for human consumption seems beyond reproach.

"Again, we're not making any medical claims here," he explained. "Soylent is not a drug, basically, and we're not testing on that level. We are designing a number of studies to catalog the health benefits, though—a lot of people are seeing reduction in triglycerides or cholesterol; others are seeing improved performance or sleep. Some things are more difficult to quantify than others, but I think we can show a lot of clearly objective health benefits in incorporating this into one's diet."

Soylenting the world

There are currently six people working on Soylent, including Rhinehart, and the company is focused on bringing the product to market. However, the plans don't stop there. Rhinehart wants to target a per diem cost for Soylent of about $5 per day, which is affordable to most and which also leaves room for Soylent to be profitable. However, the intent is also there to keep Soylent libre—once finalized, the formula will be freely available, and folks can make their own.

Indeed, Soylent already has a tremendous and healthy DIY community producing and eating their own pre-release versions. After release, Rhinehart doesn't mind if people continue making their own or pay a bit more to the Soylent company for the convenience of having pre-made Soylent shipped to them directly.

Soylent has struck a solid cord in the DIY and geek set, in no small part because of that encouragement to tinker. Cooking is something that a lot of engineering geeks have difficulty with, because even easy recipes contain "soft" directions—rather than dealing with precise quantities and measurements and conditions, they're often a lot more analog in their descriptions and conventions. Soylent, on the other hand, is solidly digital—mix precisely so much of ingredient A to receive nutrient A, mix precisely so much of ingredient B for nutrient B, then shake and consume. Rhinehart calls it "cooking at a lower level" and went on to summarize the geek appeal of Soylent. "Food is hardware," he said. "It's something that can be designed and optimized."

After developing a sustainable US business for Soylent, the next step is to attempt to commoditize nutrition outside of the first world. Indeed, commenters have picked up the commonalities between Soylent and universal nutrition food Plumpy'nut, which is often used in undeveloped areas to supplement diets. In fact, Rhinehart credits the licensing and production issues behind Plumpy'nut as one of the big inspirations behind not patenting Soylent and keeping it libre. He noted that when the time comes, Soylent would work with existing NGOs and governments with food distribution channels to attempt to get Soylent out to areas that need nutrition. One potential obstacle to overcome would be Soylent's dependence on water to become edible (something Plumpy'nut does not need), but Rhinehart stated that they could potentially distribute water purification gear with Soylent.

Soylenting my friends

But I wasn't concerned with getting Soylent to the third world on Labor Day; I wanted to get it in front of my hungry friends. I showed up to Matt's house bearing not ground beef and steaks, but rather a pitcher and a crinkly plastic bag. However, like a group of cats exposed to a new box, curiosity quickly overcame everyone, and I was peppered with questions as I mixed up a batch.

By far the most curious was my buddy BJ, who's probably one of the healthiest people I know (and also the inspiration behind my own running habit). He was the first one to hold his hand out, and he pronounced the Soylent to be "perfectly cromulent."

However, his reaction was by far the most positive. No one else seemed to like Soylent's flavorless flavor or its chalkiness. Their reactions were priceless.

Everyone mentioned how they'd drink Soylent over death, but they wouldn't eat it given a choice for anything else. There was much laughter and then we proceeded to cook up the BBQ, crack open the beers, and carry off Labor Day in fine style.

And a curious thing happened. As the day wore on, one by one, every one of my buddies came up to me in various stages of Labor Day food coma drunkenness, and every single one of them looked around, leaned in close, and confided a variation on the same secret.

"You know," they variously said, "that Soylent stuff...it's not that bad. I kinda liked it."