I was bothered by that too.
I think soylent would have a hard time beating my diet WHEN I eat correctly (some recent issues resulted into me drifting far from my normal diet, but now I am returning to it again).
My normal diet,
breakfast: toast, cheese, chinese tea (I like all colors) or matte tea (it remembers black tea, but with a less harsh taste and less caffeine)
lunch: vegetables and proteins (meat, cheese, sashimi, whatever..)
dinner: proteins (usually, fish)
and then you can sprinkle some fruit and cereal bars during the day.
When I did this diet for the first time (while ignoring my nutriotionist and doctors) my weight plunged from 125 to 100, most of that in fat, my cholesterol dropped from the dangerously high 270 to 170, and several other stuff in my blood tests that were unhealthy got fixed.
I see here lots of "healthy" people like the author, that avoid meat because it is supposed to be "healthy" that are quite unhealthy. Well, several of them are not obese, but they are obviously weak and have nutrition issues.
I met REALLY FEW non-cow eaters, vegetarians and vegans that really knew what they were doing...
(by the way, the advice that I ignored from my medics was eat more grains, like rice, and avoid fatty foods, specially red meat... I did exact the opposite and it worked, while when I followed their advice strictly I got fatter, to me it is clear that even the fat in the meat is useful and important for the body)