Protein is the only macronutrient left with generally positive associations. Fat has been considered “bad” for decades. Whose idea was it to call it fat, anyway? That’s bad marketing. The truth is, there’s nothing inherently wrong with fat. It’s just that most of eat too much of it, or too much of certain kinds of it.
Carbohydrate was generally regarded as a good nutrient until Robert Atkins came along and ruined it. The low-carb craze may be long gone, but Atkins casts a long shadow. The current popularity of the Paleo Diet among endurance athletes is very much an Atkins aftershock. The reputation of carbohydrate may never be fully rehabilitated.
This leaves protein, as I’ve suggested, as the lone unsullied macronutrient. Which is ironic, because humans require much less protein than they do carbs and fat, and protein consumption becomes “too much” at lower levels than carbohydrate and fat intake.
There are, of course, protein zealots out there who believe that more is better, with no...