I think for this parallel to be valid he'd have to be eating McDonalds or what-have-you every day. The point is variety (mostly) ensures we get everything we need from somewhere. I think it's almost assured that in the long run 100% (or so) soylent will turn out to be more detrimental than even the 'average diets' out there. BTW, I'm kinduva healthy eating nut myself, but this just isn't 'healthy eating'.