Glycemic Index of Soylent 1.5


Lol since everyone’s asking, I’d like it too!


Instead of offering to send the pdf privately, why not just give a specific time/date that you’ll be making a the official post regarding the GI and stick to it.


Glycemic Index is the devil!


Don’t worry, I fixed it.


Bumping because of severe interest in the answer. And Hello Soylent communitee !




Glycogen restriction vs. calorie restricted diets
Reduced fiber in 1.5

Thanks. It’d be nice to bring it down a little. (I’m adding soluble fiber to mine; maybe that is.)


So, does this mean that soylent 1.5 has a GI of 65 (plus or minus 6) out of 100? Isn’t that quite high?


Judging by the word “medium” to the right of the numbers, I thought it was a medium GI. A quick Google search seems to confirm this; it’s on the high side of medium.

The actual glycemic load depends on the number of carbs and the serving size:

Glycemic load of a serving of food can be calculated as its carbohydrate content measured in grams (g), multiplied by the food’s GI, and divided by 100.

For a 500-calorie serving of Soylent 1.5:

57 g * [59 to 71] / 100

Or a glycemic load of 37 (34-40). Slightly lower if fiber doesn’t count: 35 (32-38).

You can reduce the glycemic load by drinking smaller servings of Soylent (or eating smaller portions of any carb-containing food).


Given the margin of error, it might edge into the low side of high.


But, isn’t this something that could easily be adjusted downwards by changing the ingredients? Is the high or medium rating not due to the maltodextrin? I haven’t tried soylent (UK based) but I have tried some of the European ones and some of them produced sugar spikes, measured with my blood monitor and they had maltodextrin in the ingredients.

Now we know the GI, is anyone surprised?


Considering how much fat is in it now, I am a little surprised how high the GI is.

Maybe not. My somewhat uninformed guess is that the ingredients have less of an impact on GI than we might expect. But the processed and liquid nature of it it impacts GI more than assumed. If this is true, it makes sense why RA has added so much fat.

This Harvard Medical School GI and load (GL) chart shows a list of values for common foods. Because Soylent is 500g per serving and most other foods aren’t close to that, the GLs aren’t able to be compared directly (at least I don’t think so). But if we make a serving of Soylent 100grams --near that of vanilla cake, GL 24-- we get a very nice GL of 7.41 [11.4g * 65 /100 = 7.41].

Can someone check that logic?


@Conor Those numbers are a little ambiguous. Are they for an entire bag or per serving? If they are for the entire bag what is the per serving GI?


Soylent is 115g per serving.


The glycemic index is independent of serving size; the glycemic load is dependent on serving size. (@Conor posted the glycemic index.)

That is the serving size of unprepared Soylent; he’s estimating the serving size after adding water. Since water doesn’t add any carbs, and glycemic load depends on the number of digestible carbs per serving, it doesn’t matter which serving size we use. What matters is how much you drink and how many grams of digestible carbs it contains.

I’m assuming the GI was calculated with prepared Soylent. If the powder itself was tested, I don’t know what (if any) effect the water would have on the GI. Anyone?

That logic makes perfect sense if you only drink 100 calories of Soylent at a time. So, yes, a small glass of Soylent has a lower glycemic load than a large glass of Soylent. That logic holds for any food.

Another possibly useful measure is daily glycemic load. So if you are on 100% Soylent and drink one bag per day (2000 calories), the daily glycemic load would be 140 (128-152) per day.

Some comparisons:

  • 2000 calories of peanuts is a daily glycemic load of 3
  • 2000 calories of whole milk is a daily glycemic load of 65
  • 2000 calories of black beans is a daily glycemic load of 97
  • 2000 calories of Coca-Cola is a daily glycemic load of 351

So not great but not awful. I’ve found a few sites that suggest a goal of keeping your daily glycemic load under 100. Unfortunately they don’t mention any sort of dependency on body weight, which makes me question the validity of a static glycemic load for small vs. large people. If someone eats 1500 calories a day vs. 3500 calories a day to maintain a healthy body weight, is it realistic to suggest they both target a glycemic load under 100?

An easy way to lower the effective glycemic index of Soylent is to add more fat or protein to it. To put that another way, if you replace some calories from Soylent with fat or protein, your daily glycemic load will be reduced.


Ah looking closer you are right. I was getting GL and GI confused (I think a lot of us are). Considering Soylent has 43ish% of its calories from carbs and the FDA recommends a person get between 45-65% of their calories I suspect that Soylent’s GI may actually be about right for a balanced diet. Now its GL maybe a different matter. That is affected by fiber right?


Hmm. I add 150g egg white protein and 9 tablespoons olive oil per bag when preparing and 2 teaspoons of Psyllium husk powder per serving. That must bring the GI down significantly. I wonder how much.


Some folks were upset with the big change from 1.3 to 1.4 but as I recall maltodextrin was one of the top ingredients in 1.3 (it was the top ingredient in 1.0) and I think maltodextrin has a high GI so I’m guessing that amongst other reasons, one of the reasons for the kind of change we saw from 1.3 to 1.4 was to reduce the GI.


I was going to say added fiber should lower the GL by lowering the GI, but I’ve read conflicting information online as to whether or not added fiber affects GI and whether soluble or insoluble fiber has a bigger effect. Anyone?

If you offset some calories with increased fiber intake, that would indirectly lower the glycemic load even without affecting the GI.

Ignoring fiber, you can calculate the GL of the Soylent and the GL of anything you add and then add those two numbers together (similar to how you add the GL of all the foods you eat together). Total GL won’t go down simply by adding fat/protein unless you also consume less calories from carbs (not %, but actual amount). This makes sense because the glycemic index only considers carbs, not protein or fat.

I see now that there is a also an insulin index, which according to Wikipedia:

This measure can be more useful than either the Glycemic Index or the Glycemic Load because certain foods (e.g., lean meats and proteins) cause an insulin response despite there being no carbohydrates present, and some foods cause a disproportionate insulin response relative to their carbohydrate load.

Honestly this sounds like a way more useful metric than GI or GL.

Like I said above, it’s unclear to me what effect fiber has, so it isn’t possible to calculate its effect. I assume the effect is neutral or positive, but I haven’t seen definitive information yet.

The powdered oil is roughly half maltodextrin (70 g or so), but that is down significantly from 1.0 (165 g). I can’t find any information on changes to maltodextrin in 1.1-1.3, so I’m assuming the amount was unchanged.


Am I reading that right? I’ve tried as much as 70ml of canola but eventually backed down to 20ml… I just recently switched to olive oil but am still at 20ml… (1 tablespoon is about 15ml right?)
edit:PS 9 tbs would be about 1080 kcal?