I'd love to see this study replicated, only instead of "proprietary (expensive?) product", it was just 40% of your daily caloric intake.... in soylent.

There's been multiple studies I've seen now indicating that fasting does this, the questions I want to know are:

1. How much of a caloric intake drop is required?

2. How much does it matter what specific types of calories are used for the lower-calorie period? (ie, 500 cals of fast-food vs. soylent vs. prolon vs. ensure)

3. Is there any tell-tale sign we can test for indicating when a sufficient 'period' has occurred for the benefits, thus knowing we can resume normal diet?

I can only imagine if these scientists are associated with a specific product, they probably don't have a huge reason to find out if a cheap existing product (soylent/ensure) works just as well as their most-likely-more-expensive-proprietary one. But it's the first thing I want to know.