These ketosis diets have been around for a long time. My wife tells the
story of how her sister tried one when they were teenagers around 1970.
It does work for weight loss (at least temporarily) but the metabolic
state your body is thrown into does not sound healthy. One side effect my
wife and her family noticed is that it causes very bad, sulphurous body
odor. With a large family and a small house this was not appreciated.
I don't think having these kind of chemicals floating around in your
body would be good for you.
The real problem with diets isn't losing weight, it's keeping it off.
I've seen figures suggesting that 90% of dieters regain all the lost
weight within two years.
Hal