The article is pretty clear further down on the reasons for these limitations:
> The reasons are largely practical ones. Most medical school tables are not large enough to accommodate a human being larger than 200 lbs or longer than 6' tall. Donated bodies also have to be moved by students and/or researchers, and heavier bodies are harder to move, posing injury risk. Dissection is also made more difficult when a cadaver carries more fat—the dissector has to cut through the layers of fatty tissue to reach the body's organs.
But then the article also tries to hype up that not taking her donation is some kind of injustice:
> But Scott McPherson knows first hand there's something unpleasant about denying a person's dying wishes, too. "My mom just wanted to donate her body for something she believed in," he says. Instead, the McPhersons founds themselves trying to figure out an after-death plan for their mother that went against everything she'd asked them to do.
The whole irony in this is the journalist deliberately used (while true) an extremely insensitive title to get you to click, "Americans Are Too Fat to Donate Their Bodies to Science", but then tries to highlight how insensitive it is that schools won't/can't take obese full-body donations.