Stomach ache from flax seeds and dehydrated by oatmeal?



I’ve been on DIY now for about two weeks, but recently stopped altogether. I wonder if some of you guys experienced a similar thing or have some tips to share. Because I really like the idea of Soylent and also I have invested quite a bit in my recipe.

I had two problems with my recipe (, the ingredients are in Dutch though):

  1. after every meal I got stomach aches for a couple of hours, varying in intensity. I suspect it had to do with the ground flax seeds. I used 13 grams/day. I experimented a couple of meals with leaving the flax seeds out and this indeed seemed to confirm my suspicion. Has anybody else experienced this issue before? Or does anyone know of a better alternative (I use it mainly as my omega-3 source)?

  2. I had some ‘dehydration’ issues. Basically, I had a dry mouth all the time. I drank lots of water, but it left my body almost instantaneously, or so it seemed. This is the main reason I quit, because it scared me a bit. Could this have anything to do with the amount of oatmeal I used? I took 260 grams/day of Fine Scottish Oats (more than half of the total weight of my recipe). Also my skin seemed a lot dryer after my weeks of experimenting.

Well, these are my experiences. Maybe someone recognises any of this or has something to say about it. Any help is appreciated!



My recipe has 30g of ground flax seed a day and a have no issues. I also use 210g of oats a day but I’ve always drank large amounts of water and have always had dry skin but I havent noticed any changes with being on soylent. I would try putting more water in your soylent, both the flax and the oats will absorb alot of water which could be causing the stomach ache and would help with the dehydration.

  1. I would question how much total fiber you were using. 40g is quite a bit if you’re not used to it and could definitely explain the stomach ache. Might want to work up your way up to it. USDA recommends 14g per 1000 calories, but there are benefits to being higher.

  2. Not 100% certain on this one, but you may be right. Did you take creatine at all? Sodium & potassium intake looks normal. I suppose it could be the oats. You could reduce the oats and try using maltodextrin for the lost carbs. Last I read, official Soylent only uses 110g of oats. That’ll probably drastically reduce the fiber too.


Just don’t forget you normally get 50% or more of water via regular food. If you replaced it with pure soylent, you need to drink more water.


High, a dutch guy here.
I think its the oats too. When i take a lot of soylent-meals in a row, I experience stomach ache as well. I have a high amount of oats too, also from bulkpowders. Here is my recipe (less sophisticated).


Thanks for the heads-up about the fiber. I followed Rob’s newest recommendation recipe, which has 40g of fiber in it. I will try again with a little less fiber and replace some oat meal with maltodextrin.

I haven’t seen creatine mentioned before. Do you recommend it?


Interesting. Hopefully replacing some of it with maltodextrin will result in a more digestible result. Although I would have preferred to stay away from the high GI ingredients…


Some maltodextrins are higher GI than others. Soylent uses a low-GI equivelant maltodextrin.


I has similar reservations, but I haven’t had any issues. I think when combined with all the other ingredients(protein, fat, fiber), it drastically lowers the overall GI of the soylent.

The original soylent Rob experimented with I believe had Tapioca Maltodextrin. I searched for quite a while for a reasonable price to obtain it, and it’s impossible. It’s been targeted as a product for “Molecular Gastronomy,” which is a type of cooking. I tested Corn based maltodextrin and decided it was fine. Soylent soon after announced they are also using Corn based maltodextrin.

Re:Creatine, it’s up to you and your goals. I only asked because it causes your body to absorb a lot more water, thus possibly leading to your state of dehydration.


I had about the same amount of flax seed in my first DIY and I was sick for days. It was only when I let the flaxseed sit in the mix overnight. I think it leached the oil out and killed my stomach. After taking the flax out, I was fine. I switched to hemp hearts.


Do you leave any time between adding the water to your soylent-powder, and drinking it? Because the oat-powder really expands in the course of minutes. What seems wet, turns into a thick porridge. If this happens in your stomach, it sure will ache. And dehydrate. And since your recipe contains a lot of oatpowder, this can be a relevant factor.


Yes, I searched for Tapioca Maltodextrin as well, but couldn’t find it either. Interesting that Rob is switching to Corn based now. And I guess you’re right the overall mix will not be very high GI.


I drank my Soylent immediately, so I guess if the meal is then extracting water from my body, this could indeed cause the dehydration. I will try to adapt my formula so it will contain no more than 110g powder. I find that keeping the Soylent in the fridge for a couple of hours is too much of a hassle for me. I guess I could let it sink in for a couple of minutes though. Definitely will try that. Thanks.


And drinking a good glass of water right after, should do the job as well.

And: thank you! Because of your post i did this experiment this morning in my kitchten and i bet it solved my incidental stomach-aching as well:

A large cup, filled half with the fine powdered oats. Add water and stir. Add water until your spoon doesnt have any resistance. Then leave it for 10 mintutes. Try to stir again.


This part definitely defeats part of the convenience factor, but I still do it because I find that it creates the best “taste.” I had a drink last night at room temperature and remembered why I always try to put it in the fridge first. lol


@alexbuijs Is it possible you are allergic to flax? Many people that are allergic to something will experience a stomach ache and not realize it’s actually an allergic reaction.