Not claiming to be an expert on Angus, but wiki says he lived on “tea, coffee, soda water, and vitamins”. No protein/amino acids in most vitamins, although maybe they said vitamins when they meant supplements.

The obese starvation victim was mentioned in a scientific study I read. It’s entirely possible there was a link to another paper with more details but I didn’t follow it. I just recall reading that drove home for me the importance of protein while dieting.

Personally, I don’t think it’s typical at least. At the other end of the spectrum I’ve read about someone who died of starvation while still obese.

The problem is that there is no protein coming in, and burning fat isn’t going to contribute to your protein needs, so your body is going to catabolize muscle too. This includes your heart muscle. It’s common for anorexics to die of mitral valve prolapse or congestive heart failure.

I don’t know if my example or your example is closer to typical, but not a risk I would consider.

I also want to note that Barbieri died in his early 50’s. Wouldn’t surprise me if his extended starvation period resulted in a heart attack some years later.