"I don't think it's healthy," the former SI Swimsuit Issue star told E! News.
"Her face is beautiful, beautiful. But I don't think it's healthy in the long run."
Tiegs believes the rise of full-figured models is problematic because of the message it sends.
"I don't like it that we're talking about full-figured women because we're glamorizing them, and your waist should be smaller than 35 [inches]. That's what Dr. Oz said and I'm sticking to it."
James Macari / Sports Illustrated
"I thought Sports Illustrated was taking a risk by putting a girl my size in the pages," Graham told PEOPLE after her cover reveal. "But putting me on the cover? They aren't just breaking barriers; they are the standard now. This is beyond epic."
And Twitter mostly reacted in kind, giving Graham and the magazine props for her groundbreaking cover.
Tiegs was a fan of Clauson's SI spread, and posted one of her photos on Facebook with the caption, "I remember posting a picture of a beautiful swimsuit model on my refrigerator. It gave me the inspiration to have a thin, #healthy, strong body. #HaileyClauson #Motivation"