I can understand the thinking that being that much Soylent in the long term might result in some negative effects because you’re getting less of whatever might be slightly good in regular food that we don’t know about yet and the effects could accrue over time
But I think that could work in the other direction too. There might be things in regular food that are slightly bad that we don’t know about and the effects could accrue to the negative over time and someone consuming a lot of Soylent is less likely to experience such effects.
As an example, consider what is widely assumed to be a healthy diet of regular food. Do we know whether every single chemical in that diet is good? No. We say “This diet has a lot of X, Y and Z and we know X, Y and Z are all good for you and we know by studies that diets with a lot of X, Y and Z tend to be better than diet without it.”
Okay, fine, but those diets also contain many other chemicals that we don’t know much about outside of the fact that they’re not REALLY good or REALLY bad for you. Those things are just there and we consider them neutral but they could have slight positive or slight negative effects. Even if they have slight negative effects, the positivity of the diet having a lot of X, Y and Z would overwhelm the slight negative effects of the other things when comparing to a diet without X, Y and Z.
In other words, it’s impossible to compare a diet with only X, Y and Z to a diet with X, Y, Z and all the other stuff that’s just in there. We have to take the other stuff because it’s in there along with the X, Y and Z. It’s possible that avoiding all that stuff over time could accrue positive benefits.
A high school chemistry teacher in Australia named James Kennedy once made a list of all the chemicals in “natural” foods and it was long. And actually it was only a partial list because he said there are trace elements of far more things than was in his list. Anyone can google it. There’s tons of stuff in there beyond the parts that we know is good for us.