[Yep, same guy, did a search, didn't realize there was another thread.]
The long term effects are precisely what are of interest here. As a side note, these people consume more fiber than most Americans do already, but in the first version they didn't. Your feedback is precisely why this approach seems to have merit: problems can be fixed rapidly and without infrastructure costs. I find this idea interesting primarily because that's not true with modern American/English/German diets -- their problems persist for years after discovery, not days.
Conversely, my interest is not because I think this is the best diet. Quite the opposite -- as you indicate, there are reasons to eat real food. But to draw an allusion to The Art of Money-Getting, probably the best book on personal finance, written in the 1800s, too, because the basics don't change:
Take your expenses, and sort them into three categories, one labelled Needs, one Wants, one Luxuries. You will not be able to tell the difference between Needs and Wants. This is because you are human. The difference is irrelevant, as well, as punishment isn't the goal. Instead, try to limit luxuries to control your budget.
Nutrients are a need. But a lot of the MMM ethos is in drawing the line between luxury and wants differently. Having a professional cleaner is not described by my coworkers as a luxury, to them it's a want. High quality food, if the alternative supplies the same nutritional value, from my perspective, could be described as a luxury. That's the conversation this should be about. Everything else is execution.