Likely because it seems so intuitively logical that fat in your body comes from fat in your diet. Want to stop getting fat? Stop eating fat. It seems so obvious, despite being wrong at the fundamental level.
And yet, as the article doesn't quite point out, eating all the protein you like won't make you more muscular (unless you also do regular strenuous exercise).
Obviously you can't just eat your way to a six pack. If you're trying to make a point worthy of an "and yet" prefix, it's lost on me.
You can get fat by eating too much protein. Or too much fat. Intense overeating of any macro-nutrient is a bad idea. The thing is, it's harder (though by no means difficult) to overeat fat or protein.
The dangerous thing about carbohydrates is they are by far the easiest to overeat, and may have the greatest health consequences. That's a scary combination.
" If there are enough rabbits, the people eat till their stomachs are distended; but no matter how much they eat they feel unsatisfied. Some think a man will die sooner if he eats continually of fat-free meat than if he eats nothing, but this is a belief on which sufficient evidence for a decision has not been gathered in the North. Deaths from rabbit-starvation, or from the eating of other skinny meat, are rare; for everyone understands the principle, and any possible preventive steps are naturally taken."
Of course not a six pack, since the primary ingredient for a six pack is an absence of fat. I'm just talking muscle volume here. "And yet" was probably the wrong choice of words; I really meant "Indeed", I think.
The way I read it, it's poking a hole in the "you are what you eat" adage that people take at face value for "if you eat fat you get fat".
By extension of this adage, then, if you eat fat you get fat. If you eat carbs you get starchy, and if you eat protein you get muscley. We know the second two aren't true, but the first one sticks for some reason.
It's for precisely that reason that I can't fathom how even this sticks with people. "you are what you eat" (in this literal a sense) sounds like something you grow out of around the time you figure out object permanence.
