The (Un-)Official Fart Thread


There’s been no official word or blog post, no e-mail, no sticked threads, I just had to find out myself after searching around a bunch in the forums. Perhaps the folks who run the soylent blog could put up a post about the salt bug and talk about the gas issues and what has worked for certain people (from what I’ve read 1. letting it soak, 2. drinking slowly, 3. extra dietary fibre, 4. it may go away on its own after a week). I feel like I sholudn’t have had to find all of this out the hard way.


The need to supplement with ~ 1/4 tsp. of salt is an official “fix;” I think we’re still waiting on “the cure” for the gas issue. You can add supplementing with probiotics to the list of suggestions.

A stickied thread is a good idea. Tagging @JulioMiles so he’ll notice this thread.


I’ve had slightly over two days of almost 100% soylent that I purchased from a friend while I’m waiting for my smaller order to arrive. I have reason to suspect that the fish oil may be part of the problem, but I’ll be experimenting with that once my gas has resolved itself in the time I return to whole food. Meanwhile I acknowledge that I have a terrible diet in that I do not eat enough or appropriate foods, so the sudden increase in “good stuff” could cause my body to freak out.

So, the list of potential gas fixes includes:

  1. Exercise (excess protein may cause gas and you could stand to go for a walk anyway).
  2. Increase in dietary fibre (something something pseudoscience I’m not really sure IANAL).
  3. Take a probiotic (your stomach is stupid and so is your face).
  4. Let the mixture soak overnight and add oil right before drinking (theoretically the mixture absorbs more liquid rather than being coated in oil and then suspended in a liquid causing poor absorption and chalky/grainy texture, and blah blah pseudoscience soaking oats helps somehow again IANAL).
  5. Suck it up. (You probably eat nothing but fried cheeseburgers and failure, so now your body is freaking out at all of the awesome nutrients it’s been trying to live without.)
  6. Don’t use the oil. (There are reports of people having the sulfarts even on the vegan formula, but everyone is a special flower and blah blah plus I don’t even believe in vegans or Father Christmas, I’m not eight years old.)

(Take a moment to reread my post for humour value before responding. I’m just being silly. <3 )

A sticky and an official blog post would be nice.


Actually it seems the best solution to prevent gas is not to go 100% Soylent right away. Go up to 75% only and it should not occur and if you go 100% Soylent after a few weeks perhaps even months it shouldn’t begin at all.


Humor aside, since I’m probably the one most vocal about the fiber, I would like to clarify that 1) I added soluble fiber specifically, insoluble fiber would make it worse, 2) my fix was addressing bowel movements. The gas reduction may just be coincidental.

That being said, I would appreciate at least a “this is what we’re working on” from Rosa Labs, but they’re probably busy just trying to get orders out the door.


I’ve seen a lot of people say that drinking it too quickly can cause problems (because 670kcal in under 30 seconds might be a lot regardless of whether or not it’s solid), so the (un-)official list of fixes expands to the following:

  1. Exercise (excess protein may cause gas and you could stand to go for a walk anyway).
  2. Increase in soluble dietary fibre (cos you may just be pooping too fast! VROOOOM!).
  3. Take a probiotic (because your stomach is stupid and so is your face).
  4. Let the mixture soak overnight and add oil right before drinking (because coating the particles in oil and suspending the oil-covered particles in water makes it taste gross and chalky, but also because blah blah pseudoscience and soaking oats somehow helps you be less farty IANAD).
  5. Suck it up (because you probably eat nothing but fried cheeseburgers and failure, so now your body is freaking out at all of the awesome nutrients it’s been trying to live without).
  6. Drink it slowly (piggy; having so much at once will give you upset tummy).
  7. Switch out or remove the oil (because maybe fish something something and then gas).

=3 Any other anecdotal evidence or conjecture is welcome at this point (you jerk).


So I decided to do some science. I forgot to mix the oil in to the first batch I ever had and don’t seem to recall getting the farts on the first day, so after I finished off my friend-purchased Soylent I still had one bottle of fish/canola oil sitting around. Being that I don’t recall having had gas on the first day, I decided that I would consume the oil blend on its own after I was satisfied that my stomach had settled and I’d had enough normal food to rule out any lingering soylent.

So with bated breath and frowning face I have consumed one whole bottle of Soylent Oil Blend Formula and am now sitting with an upset tummy and a horrid taste in mouth, waiting to fart. I will let you know what my results are as they sound, and meanwhile I would appreciate others commenting with their own experiences so that we might discover the cause or causes as there may be many situations that are all causing one similar problem.



That much oil consumed alone is likely to cause stomachs upset anyway, that doesn’t mean it’s the cause of gas. Now that you’re used to the effects of complete Soylent a more reliable experient would be to consume the powder with and without oil on different days.


I didn’t have any gas problems the first few days that I was eating Soylent. I was eating the full 2010 calories plus eating some regular food. I did start to get gas/bloating/bubbly gut after a few days. It seemed to be worse when I started eating three meals of about 670 calories at a time, rather than 4 or 5 meals, so that could have contributed.

Now I’ve switched to only eating 1500 calories a day in three meals. I’ve also started diluting the Soylent by pouring 500ml into a Blender bottle and then adding about 200ml of water. The problems seem to have died down quite a bit. Perhaps in the future I may start eating more a day and see if it comes back like before.


There’s been a lot of hoo-hah passing for knowledge about digestive gas on the forums; don’t look it up here. Wikipedia has a lot of the science and AFAICT it’s all basically correct.

When people complain about “gas” they could be complaining about one of two issues (or both): stomach bloating/burping and intestinal gas/farting. Narrow it down to intestinal gas you still have two separate issues: gas volume and gas smell. These have two different causes.

Gas volume is mostly molecular hydrogen, carbon dioxide, and methane, and is produced by bacterial fermentation of polysaccharides in the large intestine. Polysaccharides = complex sugars and starches, including some forms of soluble fiber. Beans contain raffinose, which is a soluble fiber polysaccharide that produces a lot of gas when fermented, and humans lack the enzyme to break it down before it gets to the bacteria in the large intestine. Beano contains that enzyme, and it breaks raffinose and similar polysaccharides down in the stomach and small intestine without producing gas.

Gas smell is mostly caused by volatile sulfur compounds created as a byproduct of the breakdown of sulfuric amino acids (hence SAA). Most proteins are broken down into amino acids in the stomach and absorbed in the small intestine but SAA typically need to be broken down further by bacteria in the large intestine. These are different bacteria from the ones who break down polysaccharides.

Oils can indirectly create issues with stomach bloating and burps, but shouldn’t play a very large role in intestinal gas. Oils are broken down by lipases created by the stomach and pancreas and don’t create gaseous or sulfuric byproducts, just simpler fats and free fatty acids and glycerol. Bacteria will consume some of those and produce more byproducts but breaking down fat is a slow process and shouldn’t lead to a quick surge in gas volume.

That doesn’t mean that the oil blend isn’t the cause. It only means that the cause is not the oil itself. There could be a contaminant in the oil that’s somehow leading to a fermentation party in your gut. But Occam’s Razor says that the gas volume being experienced is caused by the carbohydrate ingredients and the smell is caused by the protein powder.

All of that is normal and happens 100% of the time in a healthy gut. Fortunately, there are also gut flora that consume gaseous volume. If the bacterial gas producers and gas consumers are balanced, you won’t get farts, and all the stink will end up in your poo. When they’re not balanced, you do get farts, and if you’ve been eating lots of SAA it’ll stink. This process will often self-balance over time, through the simple mechanics of bacterial reproduction in the presence of ample food supply.

But the interplay between flora in your gut is extraordinarily complex and unpredictable and to a large degree unique to each person. Many Soylent users will never get gas, many will get voluminous farts all day long but it won’t stink, many will get silent-but-deadly farts, some people will have tremendous issues for a week and then suddenly feel better, some may never improve and so on. No single food product will satisfy them all unless you get rid of all the polysaccharides and SAA-containing protein, which is a rather massive chunk of what we call “food”.

The best approach for Rosa Labs (eventually, once the business situation allows it) is probably to mix carbs and proteins from various sources, and/or create several lines of product. DIYers should experiment with ingredients until they find what works best for them. For the Soylent 1.0 buyer, wait to see if it gives you gas, and if it does the best bet is Beano just before every serving and patience.

EDIT: Forgot to mention - insoluble (dietary) fiber does not cause gas. Period. Or at least, not when consumed by humans. Cows can digest cellulose and that’s the main source of methane in a cow fart. But in humans it passes through the system undigested. If anything, because it speeds up the travel of fermenting poo through the large intestine, a large amount of dietary fiber should lower gas production modestly. Soluble fiber like raffinose is the fart beast.

Anyone Tried Probiotics To Prevent Gas?

The gas problem is something new to me with Soylent. I typically drink about 8oz of Soylent, every 2 hours 6-8 times a day (depending on hunger) and never experienced the issue.

In order to replicate the gas, I upped my serving to 12oz every 2 hours. At 12oz I started to see the gas issue. To test further, I upped the serving to 16oz and noticed my gas was even worse. I’m not sure what the specific cause of the gas issue is but I see a clear correlation with serving size in my case.

Can other people that are experiencing the gas issue reduce their serving size be 25-50% and see if that helps?

Anyone Tried Probiotics To Prevent Gas?

Portion size should definitely affect gas production if the polysaccharides causing the fart volume can be broken down in the stomach and small intestine. There’s a limit to how much complex carbohydrate the stomach and small intestine can break down at once; there’s only so much enzyme to go around. If you overwhelm those enzymes by flooding the system with complex carbs, the undigested portion will pass to the large intestine where it’ll make more fart gas.

If that’s the issue, spreading out the consumption to frequent-but-smaller serving sizes can and should help.


It’s been a few days. Sorry about that!
So I drank the entire bottle of oil formula and, aside from feeling a little ill from having just downed that much oil in a single go, I had no ill effects. I don’t think it’s the oil formula, and based on what others are saying, it seems like the two biggest things to try are having smaller servings at a time and easing into soylent over time.

I’d also like to see if the smaller servings help with people having major gas. Once my kit finally arrives (I’m one of the two week suckers, even though I ordered an age ago) I’ll be sure to try it myself because I had nasty problems, like I’ve had to wash things several times to get the sulfur smell to go away.


Last week, I was drinking Solylent for breakfast only, and probably only about 400-500 calories worth and all week I had stinky gas. I took a couple days off - Soylent free. Today I drank Soylent for breakfast and lunch, each about 500 calories, however I mixed it with no oil at all (and it sat overnight in the fridge). Still a very large volume of gas today, and it started within 30 mins of breakfast, but so far its not smelling like death. I’ll chime in if this happens again as I plan on drinking the other 1000 calories of Soylent sans oil for tomorrows breakfast and lunch.


Yikes and double yikes. :frowning:


As an update, I’ve recently procured another few days from a friend of mine and have tried a different approach. Days 1 and 2 I soaked and sipped, but on the night of day 2 I chugged about 200ml of Soylent so I could pour myself another glass (I had been forgetting to drink it much in the same way I forget to eat, which is why I’m on soylent in the first place) and not but ten minutes later did I have horrendous wind and horrid smells. Today (day 3) I’m back to soaking the mix overnight and then sipping at it slowly, and I haven’t had a single problem.

It really seems like, for me, the biggest problem is consuming it too quickly. I think I haven’t developed sufficient gut bacteria to handle having a whole meal suddenly in my stomach in a matter of seconds, and so it tries to evacuate as much of it as possible as quickly as possible. I can’t say whether or not soaking has actually helped, but when I’m finally on a regular subscription I’ll be happy to test that theory.


I completely agree with your assessment. If I drink mine too fast, it definitely leaves my stomach too rapidly and causes problems with gas, nausea, and light headedness. I’m sipping today with no problem. Look up Rapid Gastric Emptying and see if those sound like your symptoms.


Hate to neco this but did not see the need to dupe a thread as Lotta good info in it

Started on Soylent Wednesday all 3 meals, did share some out thru the day so it was not a full day consumed.
Last night was hell on my gut and butt. ><
Today started the gas, I’m already normally gassy (bad diet) but it was worse.
Today only had about 12 oz for breakfast then 16ish for Lunch, Going to do a normal dinner tonight and will do a slow sip tomorrow
Have not tried adding Salt to the mix, I do soak overnight and add oil before consuming. Next batch will have salt added!


I tried this and it didn’t help at all. I’m generally consuming about 1800 cal per day of Soylent. I started out splitting it into 3 meals a day. To try and cut down on the gas I then split it into 6 meals a day. That didn’t help.

Now I started taking Beano and that has been helping. I went back to drinking 3 meals a day and I’m taking 4 Beano pills with each meal and that’s just barely doing the job.

I’m thinking of finding another enzyme product with a higher dose than the regular Beano.

Any suggestions on Beano alternatives would be great.


The only thing that really helped me was getting used to Soylent. After a couple weeks at 2 meals/day, my flatulence reduced to normal levels.