All weight loss leads to muscle loss as well as fat loss.

No it doesn't.

Well, both the bodybuilding and oncology communities would love to hear your method for losing fat without losing muscle.

So, let's hear it ...

…you stay in a calorie deficit while consuming sufficient protein. You need a lot of protein to pull it off. This isn’t news. You can learn this anywhere online.

Bodybuilders explicitly do this to achieve low body fat percentages. I know. I have low body fat. I did exactly this. For most men, getting below ~14% body fat and into single digits requires you to do it. I’ve found that it’s nearly effortless in your 20s and requires actual calculations in your 30s and above.

The NIH has papers on this, bodybuilding.com has calculators for it…

And bodybuilders always lose some muscle mass at the same time. This is the whole reason behind bulk and cut cycling.

Yes, the goal is to minimize the muscle loss. However, there is always some muscle loss.

"All" is quite the claim.