The question is just how much cannibalism there was.
From Diaz’ account, the practice was widespread, but the numbers did not seem enormous. Perhaps a few people in each major town every couple of months or so.
It may have been much, much higher in Mexico City because of the high numbers of human sacrifices. A source on the net says estimated numbers that the Aztecs sacrificed vary from 20,000 to 250,000 people per year. That is a lot of meat, but there were about 5 million people in the Aztec Empire.
Diaz indicates that the arms and legs were taken for food, but not the head or torso. Hard to know exactly when you do not speak the language and are at war.
100,000 would easily be within the capacity of a 5 million population. It would be 1 of 50 people a year.
From animal analogies, one person would produce about 50 lbs of meat, or about 1 pound of meat per person per year.
From every account I've read the Aztecs were a very cruel, disciplined, and purposeful race, rather like Mesoamerican Nazis. For example, the neighboring nation of Tlaxcala was surrounded, but not conquered outright by the Aztecs. They let only enough food enter to avoid mass starvation, and kept the population alive to wage a continual uneven war in order to obtain sacrificial victims. Once liberated by Cortez, the Tlaxcalans took a full measure of revenge against the Aztec people by filling out the Conquistador army. Without the Tlaxcalans, Diaz is very clear that the Conquest would not have been possible.