Well, the oat flour has about 40 grams and the isolate is another 102 grams, or about 140 grams total. That's an entire small chicken. 20% of your calories from protein actually seems respectably high to me. Probably plenty to build all the muscle you want, despite what the current bro-science says. Especially if all that exercise ups the amount of Soylent you need in a day, or forces you to supplement with other sources high in protein.
I see, hmm oat flour seems really awesome. I'm gonna have to get some of this soylent, that or start eating more oats. :-)
I've never heard of Spirulina, but oat flour is my own personal super-food. I use it as a meal replacement, mixed about 3 parts oats to 1 part protein powder mixed with water. Maybe some dextrose thrown in if you need it a bit sweeter. I love the stuff and I'm glad the guys at Soylent are making it a large part of the formula.
You could just add protein powder?
I suppose but the whole point of this Soylent is to be a meal out of the box, no changes needed.