Soylent = Witch's brew on Reddit


Soylent: A toxic witch’s brew that will ruin your health

Check out this huge anti Soylent rant on Reddit.

If you expose yourself to Soylent, you’re insulting your body with a witch’s brew containing a variety of nutrients, some of which impair each other’s absorption and some of which interact with one another to produce carcinogens. As an example of the problem, note that when zinc and iron are administered at the same time to subjects, the subjects absorb less iron.12 When zinc is administered 30 or 60 minutes before iron, the inhibitory effect is not seen. Thus the inhibory effect lasts less than 30 minutes, which should hardly represent a practical issue for normal people eating actual food, whereas people who seek to absorb all nutrients through a single food substitute like Soylent will encounter problems like these. My suggestion would therefore be to stay away from it.


All I can say is the person didn’t do their Soylent research. It is recommended that you chew gum, so his ‘chewing’ argument is a moot point. The author of that post is also making stuff up as they go along.


Well I heard from my brother’s friend who knows a nutritionist that corn is bad, mmkay. /s


I didn’t get the jist of how epic the rant was from your original post.

The late Jacques Ellul argued that the city represents man’s ultimate rejection of God. The man did not live to see the day humans came up with the idea that they can live without food. We cause suffering to ourselves by isolating ourselves from the totality of life. The further we manage to isolate ourselves, the worse the suffering will inevitably get.

Soylent represents a significant step in the effort to figure out how to go on living independently of the survival of the biosphere. It is as if we were to spit in the face of God. It should come as little surprise that this stupidity is the product of a software engineer.

Bahaha. It does seem like the poster is serious since he cited some sources, but he apparently has a very rudimentary understanding what Soylent is. I also like his argument that 2000 years ago people consumed more vitamin C, therefore Soylent doesn’t contain enough (that’s some logic there).


I also like the fact that after the demise of the biosphere we will still have corn and rice and oats to make Soylent from.

Also the bit about how up till now no one has ever eaten vitamin C and fat in the same meal. No one ever had orange juice and bacon in the same meal.

When vitamin C and fat are both present in the stomach, vitamin C causes the formation of carcinogens, rather than protecting against cancer.10 In a natural diet, you’ll rarely encounter a high amount of vitamin C and a high amount of fat in the same food product.


Lots of things are carcinogenic. Its our immune system’s job to fight off cancer and get rid of cancer causing substances. I bet someone drinking soylent will be more likely to fight off cancer than someone who isn’t getting proper nutrition.


Yeah, ignore that lunatic. They’re using a three day old throwaway account.


It’s also posted on the “deep ecology” subreddit. Here’s what their sidebar says:

We are in the middle of the 6th extinction event, and we are the cause of the problem. It is vital that we become the solution.

So to put it bluntly (Not trying to insult with name calling), it looks like they’re a bunch of hip, all-natural vegans.


Deep ecology, from how I understand it, aims to dismantle civilization, bring the world’s population to the millions (as opposed to billions) and have us live as our prehistoric ancestors did, all in order to save the environment.

Soylent is the very antithesis of that philosophy.

Personally, I see where they are coming from, and agree with their ultimate goal (to save/revitalize the environment), but I don’t agree with their way of reaching that goal. Without diving too deep (and making a TL;DR post!), I believe Soylent is part of the solution.


It was nice of the author to provide some references to papers backing his arguments. I’ll just drop my thoughts on each here. I’m doing this mostly for my own benefit, but maybe you guys would be interested in looking it over. Each citation in the rant gets a corresponding number in my list here. a provides links, b provides a relevant summary and evaluation of each citation, c is where I’ll try to link it back to soylent and see if it matters.

  1. Chewing is important for brain health: reduces dementia and improves students’ test scores. Soylent does not involve chewing.
    a. Links: Dementia article, Dementia paper, Chewing gum test scores article
    b. The dementia paper’s authors’ conclusion is that even though there is a strong correlation between tooth loss and cognitive impairment, much of it can be explained by age and education level. As people get old, they happen to lose their teeth and go crazy, but that doesn’t mean one causes the other. Poorly educated people tend to go crazy more often and also never learned how to take good care of their teeth, but that again doesn’t mean one caused the other.
    However, even correcting for age and education, there was still a statistically significant correlation between lack of chewing ability and cognitive impairment. The reasoning for this is still unknown. Other studies hint at a causal relationship between chewing and increased blood flow through the brain, and through that, improved cognitive functionality.
    The chewing gum and test scores article was about research funded by Wrigley, in case that’s a deal breaker for some people. It found statistically significant improvement in test scores for students who chewed gum while doing homework over 14 weeks. The article suggests that this can be attributed to gum’s shown ability to reduce stress and anxiety.
    c. We don’t know if the dementia paper’s tooth loss to dementia correlation can be generalized. Since the tooth loss was evaluated by a survey asking participants how well they can chew food (easily through not at all), this could be a psychological effect: a correlation between perception of inability to chew with dementia. We cannot generalize “tooth loss” to “chewing” either: it could be that merely the presence of intact teeth (regardless of chewing activity) prevents dementia.
    From what I’ve gathered, this is something to keep in mind, but not a dealbreaker for soylent as a meal. Chewing gum is probably a good idea for everyone, especially for people like us who are pushing up against the edge of nutritional knowledge and want to be safe. If a large percentage of your diet is soylent, you may want to consider chewing gum as a sort of precaution.
  2. Carbs consumed as part of a liquid are less satiating, causing people to overeat and become obese. Soylent is a liquid.
    a. PubMed abstract of the paper, one interesting cited article
    b. The linked paper is a review of research experimenting with the difference between carbs consumed as part of a liquid or solid. Findings were generally that after drinking beverages sweetened with caloric or non-caloric sweeteners, people ate the same amount of food and reported the same satiation levels. When eating the same number of calories in solid form (even if it was solidified only by adding gelatin and sucralose), they reduced their intake during a subsequent meal.
    I found one study particularly interesting, where researchers gave participants sucrose-added fruit-flavored juice, calorie-free fruit-flavored juice, orange juice, or milk, and compared their consumed calories in the provided lunch afterwards. Men ate the appropriate amount less food for all beverages, while women ate as though they had not just consumed any calories.
    c. I don’t think this is at all relevant to soylent. Soylent is not simply water with a little bit of simple carbs sprinkled in. Soylent’s got complex carbs, fat, protein, and fiber. What we need to see is a comparison of satiation when comparing a balanced meal to the same meal, but blended. Also, since satiation is such a psychological effect, I imagine the thickness of the soylent shake and the knowledge that this is a balanced meal can affect perceptions of fullness. Finally, we have tons of anecdotal evidence (even from people who tried Soylent just to write a blog post and say “I hate it”) that it is really filling and almost even difficult to drink too much.
  3. (As more evidence for the previous point) Mice given sugary liquids ate more calories than mice given sugary solids or a standard diet. Soylent is sugary and therefore will be less satiating to humans.
    a. Main article
    b. Results are exactly what you’d expect. Mice given liquid sucrose ate a lot more than mice given solid sucrose, and the same for liquid and solid fructose. The mice who ate liquid sucrose (and therefore ate a lot of it) got fat. I’ve got no problems with the study.
    c. Completely irrelevant to Soylent, possibly relevant to some DIY recipes. Rosa’s Soylent has no sucrose or fructose (the complex carbs break down to glucose and sucrose is comprised of glucose and fructose, but that still doesn’t mean much). If you add sucrose to your DIY recipe, be aware that it might (maybe, possibly) be just as filling as if you left it out.
  4. Liquid foods leave the stomach faster. Soylent is a liquid food.
    a. Article abstract
    b. This was a study with 9 participants (that’s small). Some were given a sports drink with carbs and protein, and some were given cereal and milk with similar amounts of carbs and protein. Glycemic load was measured at multiple points as they ate and rode a bike afterwards. People who had the sports drink had a higher glycemic load. The authors believe this is because the liquid food moved through the digestive system faster than the solid food.
    Um, what? No. Their sports drink was probably flavored with sugar. The real effect here is the difference between simple and complex carbohydrates. I’m sorry, David Connor, but you’ve got to read up on basic nutrition.
    c. The citation’s conclusions are wildly off. Even if this were evidence to support the claim that liquid food moves through the stomach faster, how is that a bad thing? The reddit guy doesn’t connect this back to anything by saying “Since the stomach empties faster, you feel hungrier” or “Since the stomach empties faster, you get a high glycemic load which leads to obesity.” Completely pointless.
  5. Fruits contain acids which help reduce the insulin spikes caused by the fruits’ sugars. Soylent has no acids and will therefore spike your insulin.
    a. ASU blog post about the research, The research article itself
    b. The article shows that vinegar (which happens to be acidic) or peanuts, taken before high-GI meals, reduces the insulin spike. Other studies have found similar results. I don’t think we can really say what the ph of peanuts is. One website claims they’re pretty neutral, another (sketchy looking one) claims they’re highly acidic. I don’t think showing that vinegar lowers an insulin spike is the same as saying fruit acids lower insulin spikes.
    c. Again, the reddit guy is misrepresenting the results of the research. And again, even if the research did show that fruit acids help prevent insulin spikes, Rob has suggested that the GI of Soylent is pretty low and won’t be causing insulin spikes anyway. Not a problem.
  6. Continuing off the previous point, an acid found in some plants can delay glucose absorption in rats, lowering the glucose and insulin spikes.
    a. The referenced article, the published article, the wikipedia article on HCA which contains many references which rule it out as a dietary supplement, one study showing no effect on obesity
    b. Researchers injected sugar, with and without hydroxycitric acid, into the stomachs of rats. The rats with HCA had significantly slowed glucose uptake. Since the full text won’t load for me, I can’t comment on dosages or anything else, though I suspect they injected a large amount of HCA.
    c. Wikipedia’s examples of plants containing HCA are both things I have never eaten, and likely will never eat. Not particularly helpful. Since I don’t know the dosages of HCA in the research, I don’t know if it would extrapolate to actually eating the plants, but I’m guessing you’d need to eat many hibiscuses before you’d get enough HCA to effectively slow down one hibiscus worth of sugar. I also don’t like that “a meta-analysis published in 2010 revealed that gastrointestinal adverse effects were twice as likely for users of hydroxycitric acid”. Yeah, those natural plants are so great for our bodies. I sure am glad there’s no HCA in Soylent.
  7. Soylent adds some vegetable nutrients important for human health, but if they don’t come from actually eating the vegetables, you don’t get the benefits.
    a. Article on PubMed, full text
    b. Rats were given tomato juice, broccoli juice, a mixture of both juices, or lycopene as control (found in tomatos, thought to help reduce prostate cancer, but not much evidence for it). Rats who ate just one veggie had fewer and smaller tumors than those on the control diet, and those who ate both veggies did the best. The authors’ conclusion was that varied diets are good and that further research on dietary prevention of prostate cancer should take into account that there are many nutrients which can affect cancer rates.
    c. The study doesn’t exactly back his argument. It’s very uncertain how much effect adding straight-up lycopene to a diet would cause, but that doesn’t mean we can’t replicate the more complicated effects given enough knowledge of how these nutrients interact. Definitely something to watch, but currently not a big deal for Soylent. Also, he’s completely wrong about the ingredients: Soylent 1.0 has no lycopene.
  8. This one is a bit of an oddball. It’s a link to an entire book, which he uses as support for saying that interactions between phytonutrients are extremely common. I don’t doubt it. All it means is that we need to add multiple ingredients in the right ratios in order to get certain effects (like vitamins D and K or calcium and magnesium). Since we don’t understand many of those relationships, we can’t accurately replicate them in a soylent recipe yet. Doesn’t mean it’s not possible, but at the moment someone on a pure soylent diet may be missing out on phytonutrient interaction benefits we don’t yet know about. Luckily, we know a lot about the nutrients which are necessary for humans to survive, and hopefully we’ll learn about the ones which just optimize our lives in the upcoming years.
  9. As an example of the importance of phytonutrients, women who consumed both green tea and mushrooms had a 89% lower chance of breast cancer than woman who consumed neither. Soylent cannot yet replicate those interactions, and a 89 lower chance of breast cancer is a really big deal.
    a. Full text
    b. That’s pretty much what the study found. People who ate mushrooms and drank green tea had a lot less breast cancer. This page provides some critiques (e.g. Maybe people who eat mushrooms eat less of food X, and food X actually causes breast cancer), but nothing that would invalidate the study.
    c. It seems to me that no matter what whole foods you eat, you’re never going to eat all of the foods which have benefits in a single day. So, I should eat mushrooms, drink green tea, eat tomatoes, eat broccoli, drink vinegar, etc. With time, we will learn what exactly causes each of these benefits, and we will be able to isolate them. For now, even people eating real food are missing out on a lot of these benefits. Soylent says “okay, forget about it, we’ll just focus on making the best of what we know (which is at least good for the necessary nutrients).” It’s a tradeoff that I’m willing to take, but it may not be for everyone.
  10. Combining all nutrients into the same product (as soylent does) will have reduced effect compared to taking them separately.
    a. Original link, abstract on PubMed, full text
    b. N‐nitroso compounds formed in the upper gastrointestinal tract have been identified as carcinogenic. Vitamin C can prevent its formation, but as those compounds are fat soluble and vitamin C is not, the carcinogens can go hide in the fat to cause problems. In fact, for somewhat unknown reasons, vitamin C + fat was worse than just fat alone. Sure, looks fine to me.
    c. There are countless interactions between things we eat. Many are good, many are bad. I’m sure there are combinations of vegetables with interactions we would consider bad, but that wouldn’t stop doctors from recommending eating a variety of veggies. This is one issue that pretty much no diet to date has been able to tackle, just due to lack of information. As that information arrives, we’re going to have a choice between micromanaging food choices (“Eat carrots and peas together to reduce skin cancer rates, but increase Crohn’s Disease chance. Eat carrots and corn together to reduce heartburn symptoms but increase colon cancer chance.”) or using an intelligently designed soylent-like concoction which optimizes for factors which we can quantitatively evaluate. It’s a long ways off, but we’ll get there some day, and when we do, it’ll be clear that the soylent philosophy blows the others away.
  11. Hunter-gatherers used to have more vitamin C than the RDA recommends. Clearly this means the RDA is wrong.
    a. It’s paleo.
    b. I don’t get paleo.
    c. Reddit-dude says it’s widely accepted that humans benefit from more than the RDI, but only provides a citation that says that hunter-gatherers had more than that. That’s not evidence, that’s an appeal to nature.
  12. Zinc inhibits iron. Soylent provides them both. People on Soylent will not get the amount of iron they expect or need.
    a. Full text
    b. People who had fasted overnight were given iron not usually found in diets (which could be identified later) without zinc, and with zinc at the same time or up to an hour before the iron. They later checked for their marked iron in the bloodstream. People who had iron within 30 minutes of having zinc had up to a 40% reduction in absorption. There have been other studies on the interactions between zinc and iron; this one specifically focused on finding the period of time for which zinc inhibits iron.
    c. The article says “the threshold for this inhibitory effect was at a Zn/Fe molar ratio of 5:1, and a 28% and 40% of iron absorption inhibition was observed at a Zn/Fe molar ratios of 5:1 and 20:1, respectively.” Unless I’m mistaking the meaning of “molar ratio” or Rosa Labs isn’t providing the amounts of just the minerals themselves, it looks like the Zn/Fe ratio in Soylent is 1:2, which would mean there is no inhibitory effect. It’s good. There are plenty of other inhibitory effects between vitamins and minerals, which are probably not all accounted for in Soylent’s formulation, and this is another discussion topic which has come up quite a lot. We can try to find the optimal micronutrient ratios and optimize around them, or possibly create a “morning soylent” and an “evening soylent” to separate things out. I don’t see how whole foods help this, though. Looking over some lists of foods high in zinc and iron, it seems to me like they’re in a lot of the same things (meat and beans) and often are part of the same meal. How is that any better than Soylent?

Okay, I’m done. That took a long time. Sorry, @Karunamon that I didn’t ignore the lunatic, and sorry, @ravenvii that I dove too deep and made a TL;DR post. I just wanted to see if any of his sources were things I hadn’t heard of before. I learned some new things, at least. Mushrooms and green tea reducing breast cancer by ~90% is pretty cool, and it was fun to read about the differences between solid and liquid sugars.


Thanks for that amazing breakdown, @austonst. Have you considered posting that to the Reddit thread?


This is redundant, but a sweet-dark chocolate thank you for the analysis.
Please post a variant to Reddit if you haven’t already.