Soylent 1.5; Rosa says its Couscous, but does Harvard say its Mac & Cheese?

I’ve dwelt on this Soylent link often, which deals with the Glucose, Glycerine, and Carbs in general. I am very grateful to have the information from Rosa Labs.
And I had good feelings (perhaps irrational) that they found Soylent 1.5 comparable to Couscous. But when I followed their link to the Harvard page, and did the analysis, I came to a far different conclusion.

To me, the low Glycemic Load (GL) of 9 disqualifies Couscous as being anywhere close to Soylent, especially given the proximity of Mac & Cheese on both GL and Glycemic Index (GI). Ok, Rosa only claimed that the GI matched Couscous, but I don’t find much comfort there.

Am I overlooking something?

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Yes, GL is dependent on serving size. If you drank half as much Soylent, you’d have a fraction of the GL.

Edit (to clarify where I’m going with that): GL in this context doesn’t really mean anything, because serving sizes are pretty arbitrary. It would be more meaningful to look at total GL for the day, and to compare that to what’s recommended.


We have a new winner! Thank you, @codemaker, I did overlook that, I’m still finding my feet with these numbers. Here are the serving adjusted numbers which still accounts for dietary fiber, the other component of GL. Hamburger Bun has a matching GL per gram number, and quite in the ball park for the GI, which doesn’t account for the above mentioned fiber.

Am I hopelessly in left field, or is this batter up?

@codemaker, I see your edit now. Yes, its probably fair to say that I would not eat hamburger buns as my sole source of substance, if that is your point. Likewise, a small portion of Soylent would be a minor G load. But from an insulin perspective for total meal replacement, which does Soylent resemble more, couscous or hamburger buns? It would seem couscous is not in that league. But kudos to Rosa for swinging for the home run. I’m cheering from the stands.

A 157-gram serving of couscous has 176 calories.

A 100-gram serving of Soylent 1.5 has 500 calories.

That’s why the GL is higher though the GI is about the same. 1.5 is nutritionally and calorically denser per (dry) gram than the (presumably cooked! and not dry) couscous. The serving is actually larger than your gram measurement would suggest. The serving of couscous is only about a third of a meal, while the 1.5 is a full meal. You’ll have a smaller glycemic load if you drink less of it at a time.


That’s right; you don’t want to weight-match “servings.” You want to calorie-match to a meal total, something like 500 kcal, or 666 kcal. Then you’ll have a better basis for comparing a meal of hamburger bun to a meal of Mac & Cheese to a meal of Soylent.

Am looking forward to seeing your results.


Thanks @asympt and @MentalNomad, I think I am on the same page. I would add to your suggestion with this thought; why include fat calories?. I started down this path, and I am blown away that Excel is locking up as I try to add the calculations. Ok, I stop until reboot. But I note that the Harvard study does not include calorie/gram info.
Thanks for you patience,

Just to be clear, you’re not linking to a Harvard study. It’s just a page on the Harvard Medical School web site. Those numbers are from the article “International tables of glycemic index and glycemic load values: 2008” by Fiona S. Atkinson, Kaye Foster-Powell, and Jennie C. Brand-Miller in the December 2008 issue of Diabetes Care, Vol. 31, number 12, pages 2281-2283.

I do not understand what you’re asking, or what you’re referring to.

@Kimo, If the hamburger bun has ~110kcal (just a rough guess, you might have a better number), you’d need to eat ~18.2 of them in a day to reach 2000kcal, which would have a daily GL of ~164.

The daily GL of 1.5 is 4*35=140, which is higher than the recommended target of 100. It’s not horrific, but it’s not perfect either. They’ve said they’re trying to bring it down in the next version.

Daily GL of 2.0 is 83.5, which is phenomenal.

As far as insulin is concerned though, I really have no idea. I’m reasonably sure that both 1.5 and 2.0 are safe, knowing how much better they probably are than the sugary diets most of my family lives on, but I don’t really know enough yet to say more than that. Nice job trying to learn all this stuff by the way, it’s a lot to take in but you won’t regret the effort you put into it.

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@codemaker, @asympt and @MentalNomad… thanks for your insightful responses. I have read them carefully, but I have precious little time to respond in kind. You have all helped to keep me on an even keel, and my immediate plans include upping my exercise, and procuring a glucose meter. I haven’t tried the 2.0 liquid yet, but I reluctant to deviate from the powder, in spite of the greater carbs.