No, the best way to find out is not to try. The best way to find out is to study, on a meaningful sample size and with a well documented process and at least a modicum of scientific rigour.

This. FFS your body is not a car and you can't (well, not yet) replace parts of it if you fuck it up. You can't stop people from trying but I don't think most of them fully realise the danger they're putting themselves in.

Seconded. Playing with nutrition is the same as playing with any other chemical you do not understand very well. You can certainly do it, but chances are you will do the wrong thing and mess up.

The way I see the "we do not understand nutrition" argument is that we can tell some types of very bad nutrition: lack of vitamin C, lack of amino acids, etc. but we cannot design good nutrition. Soylent is bad. We can see that. However, if it was better, if it included all the known macro- and micronutrients int the ideal proportions, from some wholesome looking sources we could not tell whether it was actually good.

I am starting to come to the realization that all good kills us eventually, and all we are really trying to do is to find a diet that kills us the slowest.

I think most people are unlikely to exclusively drink Soylent. I tried Soylent, and rather enjoy the taste. I could see myself drinking it for breakfast instead of eating sugary cereal. If you're starting from the point of having perfect nutrition, you don't need Soylent. Most people, however, eat junk food and it's hard to eat well when you're busy. For the average person in a rush, replacing a meal with Soylent may be an improvement.

I will take a sugary cereal over Soylent for at least the reason that cereal typically has some fiber and iron in it. Also, just eat oatmeal. Less sugar, whole grain, more nutrition.

Or, if you insist on Soylent-like stuff, go with something that has been around for a bit longer: Ensure.