Fiber - what's the best supplement for 1.4?


What the best type or brand of supplemental fiber for 1.4?

Shouldn’t it be a mix of soluble and insoluble fiber?


I don’t know if it’s “The Best”, but I have had good luck with Metamucil Smooth Powder.

I put 4 teaspoons in a bag of Soylent 1.4. It doesn’t seem to change the flavor and has the added benefit of making up for the little bit of iron that 1.4 is missing.


Thanks for the suggestion. I believe Metamucil contains psyllium husk.

Soylent 1.4 is backing me up really bad. I tried one pill of psyllium husk with each Soylent meal, but that didn’t help.

I’ve read on the internet and here on discourse that psyllium husk slows down food’s flow through the body because it contains a lot more soluble than insoluble fiber. That seemed consistent with my results taking psyllium husk with version 1.2.

Since I have the opposite problem, I looked for sources of insoluble fiber that do not have a lot of other things - like high carbs or sugars or soluble fiber. I was surprised at how hard that is to find. So right now I’m eating a lot of celery and popcorn but I wish I could find another option – preferable one that would mix with Soylent.

The prior versions had insoluble fiber in the oat flour. So I thought about adding oat flour. The problem is that when they reduced the oat flour in Soylent, they replaced some of the carbs with other sources. So if I add a lot of fiber with oat flour (for example if I try to add back the 12 grams of fiber that they took out) the carbs are going to be extremely high.

Anyone have any additional suggestions? Do I have this soluble / insoluble thing right?



When I first started soylent it seemed it was not really moving through me at all. I’ve been using psyllium husk powder mixed in and it does the trick for me. My digestion, and its “end result”, has been better than it ever was before soylent.


How much are you using?


About 20-24 grams (still fine tuning) of this per bag; but I only consume 3/4 of a bag per day, so take that into consideration as well.


Wow that’s a lot. I suppose I wasn’t using enough when I tried the psyllium husk. I’m giving it another try but I’m going to ease into it rather than go straight to the level you are using.


I can really say it is a lot or not. It is what seems to work for me, and (including what is in Soylent by itself) is only 4% over the normal RDA with my consumption pattern.


Soluble fiber might slow transit time compared to normal, but not slower than constipated. It causes the ‘output’ to be much more water-rich, maybe even fluffy. And that’s a good thing for your problem.

EDIT: I missed that you tried one pill of psyllium; that’s your problem. If you’re doing pills you need A LOT more.

Since you have psyllium I say try it for a couple days more.

  • Up your dosage. The guidelines in the packaging are usually conservative.
  • With each meal you’ll need at least a rounded tablespoon of pure ground psyllium husk (not sure how many pills).
  • It should be enough that if you add it to your mixed pitcher and let it sit for a few hours, the consistency will get much thicker and a little weird. (Which is why I only add psyllium immediately before drinking.)

I’ve been adding ground chia seeds to mine, for fiber but also taste. I grind them myself in a blender. They do have a good bit of fat in them, as well. (Although it is skewed to omega-3) I then add masa/corn flour to get to a carb/fat ratio I want.

Another option is wheat dextrin, which is what’s in Benefiber. And it may be your best bet. It’s soluble like psyllium, but not fermentable so less gas issues, and tasteless and non-thickening.


Try PEG 3350 or milk of magnesia.


I’ve been using this:

I can only do half a scoop before the slime taste becomes overwhelming.

Also it takes a few days for your system to get used to it.


what kreyagg said. and i only add 1 teaspoon and it’s great.