And as far as this soylent stuff is concerned wasn't it proven that supplements aren't very good and you need actual food to be healthy?
While I do think this guy is a nutcase in general, there's nothing inherently wrong with the concept of soylent. I've been living off the European "Joylent" for nearly a year now and have never felt in better health.
As long as the body is getting everything it needs in a form that it can correctly process, it will be healthy. The biggest concerns are "is there anything missing that the body needs that wasn't accounted for?" and "are the ratios/quantities really correct?". Of course, these are also valid concerns from any normal food intake if you don't vary your food a lot, which is - in the modern day and age - an increasingly common situation.
It's important to remember that it's not a "supplement", but a "food replacement". Supplements are - as the word suggests - something to supplement an existing intake giving you the things you might be missing. A food replacement on the other hand is designed to give you everything you need. Whether or not it meets that goal is a matter of debate, but there are actual food scientists researching that actively at all the major suppliers of these 'soylent' products.
(to note: the common wording amongst consumers of these products and in this reply here uses "Soylent" (upper case S) to refer to the specific brand, and "soylent" (lower case s) to refer to the type of food in general. Soylent is a soylent; Joylent is a soylent; Joylent is not Soylent)