I suspect most people considering Soylent aren't exactly eating like Michael Pollan in the first place. Anecdotally, I know several people who subsist on diets of fast-food takeout washed down by multiple liters of soda. It seems credible that Soylent might at least provide better nutrition than that. The scorn directed at Soylent by many of the Hacker News commenters strikes me as misdirected given the relatively poor quality diet of many Americans.

I have used other commercially available meal replacement shakes in the past - most don't even attempt to deliver complete nutrition beyond covering each of the major macronutrients (protein, carbohydrate, fat). There seems to be room for improvement and innovation in this market.

The guinea pigs for Soylent aren't going to be on a multi-month voyage across the ocean or the antarctic tundra without access to other food. If they do encounter deficiency issues, they can simply reintroduce other foods without suffering catastrophic effects. It takes a special kind of stubborn to really deprive yourself to the point of serious deficiency.