Why don’t we eat more of the most abundant protein on earth?

Being old with a bit of a magpie brain does have occasional compensations, like when some whippersnapper johnny-come-lately gushes Why don’t we just eat grass?.

So can we cut the animal out of the loop and mechanically turn grass into milk?
Yes! Both Imagindairy and Perfect Day are creating artificial dairy¹! …

1. OK, they’re not feeding grass into a mechanical cow - but rather genetically modifying various micro-organisms to be able to spit out the necessary proteins for milk.

It gives me the opportunity to blow a few cobwebs out of the way, do a quick online search, and point them to the pioneering work of the great NW Pirie (never, ever, Norman). Leaf Protein: And Its By-products in Human and Animal Nutrition is the long version, and there are any number of shorter articles. Leaf Protein as a Human Food — behind a paywall at Science — is as good a jumping off point as any, and here’s the motherlode.

Rubisco, the protein that drives almost all photosynthesis and is the major component of “leaf protein”, is far and away the most abundant protein on earth. Pirie’s protein fractionation machines seem to me to be a much more sustainable and personally attractive option than any of the cellular agricultures currently on offer.

Why has nobody brought leaf protein to market? I’d eat it.