[milesvp]

I imagine this to be a problem as well. One of the things I've been starting to hypothesize a lot about is gut biome effects on diet and nutrition. If you just up and change your overnight, your gut flora doesn't have time to evolve to the new conditions. I'm also starting to suspect, based on the popularity of month long elimination diets, that a month is the amount of time it takes for gut flora to significantly change, and that at the least you'd want at least that much ramp up time.