[ChuckMcM]

That is the same bunch, they would refute the statement

"... if a human nowadays were to try to eat purely raw vegetables, their digestive system wouldn't be able to extract enough calories per day to make up for the energy used to digest and stay alive."

Which is in the antecedent comment.

[freehunter]

I guess what I missed in my post (deliberately) was tying this diet to weight loss. To lose weight, simply put, you take in fewer calories than you burn to stay alive. That's the gist of why my coworkers do it. If they get 1400 calories usefully extracted from their diet but they need 2000, they lose 600 calories every day, 600 calories which the body then makes up by burning fat. Even if they could extract 2500 just from cooking the food.

The human body is incredibly designed to not die if you don't eat anything. Basically, you have to not eat anything PLUS not have any useful fat left to burn PLUS not have any extra muscle to burn. Almost everyone in the Western world could go a month without eating and only suffer from lethargy and possibly a lack of non-fat-soluble vitamins. Eat nothing but take a multivitamin and you're theoretically good to go for months. There was the study published on one man who fasted for a full year and suffered no health detriment.

I tried to dodge that direct statement in my original post because I am not a health professional, I know nothing of the science behind the diet, and I'm not trying to make the argument that the diet would be a "good" way to lose weight.