Yeah, this looks like one of the (many) downsides of the quantifiable self.
Nutrition professionals almost always advocate for diversity, but the Internet-wisdom thing is this approach. I guess it's just easier to do the simple math of in minus out (instead of actually trying to understand the nutrition of a complex organism).
Yes, of course, but - still - it's "Internet-wisdom". And mostly from fitness communities which may or may not be adequately knowledgeable.
The split thing could make one focus too much on macronutrients, possibly eating the same thing over and over to hit the desired macros, while overlooking micronutrients. Yet, if one followed the simplest nutritional advice (diversity) instead of Internet-wisdom, that would be addressed.
Nutrition professionals almost always advocate for diversity, but the Internet-wisdom thing is this approach. I guess it's just easier to do the simple math of in minus out (instead of actually trying to understand the nutrition of a complex organism).