> but we haven't yet mastered the nutritional content of real food to the point where we can confidently say it's safe to eat Soylent or another similar product regularly.

I'm not aware of any ill effects from consuming meal-replacement shakes like Ensure regularly, and they've been around for quite some time. In some instances people have been sustained on them for fairly long periods.

Would I want to consume them exclusively for a long period of time? No, like you, I would start becoming concerned about nutrition. But drinking them regularly for long periods of time or even exclusively for short periods of time seems like it would be fine. People eat lots of less nutritious foods just as regularly.

The real question for me is what is Soylent supposed to offer over older equivalents.