No, the 'opinion' that AA women are larger and like being larger is stereotyping an entire race of women.
Maybe because it's true?
http://journalism.nyu.edu/pubzone/race_class/othergirlsstuff.html
http://obesity1.tempdomainname.com/subs/fastfacts/Obesity_Minority_Pop.shtml
http://healthlink.mcw.edu/article/1021047874.html
There's many more links available if you google the topic.