I've done something similar, but with low carb veggies and broth instead of the greens supplement. Gives sort of a placeholder soup for meals.

Can't blame Long for wanting to make a few bucks. But I don't think his research area gives him much advantage when it comes to micronutrition, and when it comes to the macros, the cat's sort of out of the bag, protein and carbs are the big movers when it comes to mimicking the fasted state. I find with a more ketogenic diet--I'm never far from the sort of edge of euphoric state that some people report with fasting, except that it occurs when I'm a couple of hours past my usual meal time, instead of a day later.