The Doc was on "TMZ Live" and praised Tess Holliday for not only challenging society's mold of body image, but also for getting recognized by Cosmo for doing so.
As we reported ... Piers blasted Cosmo for making 33-year-old Tess a cover model. He called the choice a "load of old baloney" given Britain's "ever-worsening obesity crisis."
Dr. Phil says Piers, who is a friend of his, is essentially body shaming when he says it's wrong to recognize Tess in magazines.
She's firing back at Piers too, saying ... "To everyone saying I'm a burden to the British health care system, I'm American so you don't have to worry about my fat ass. Worry about what horrible people you are by whining about how me being on the cover of a glossy magazine impacts your small minded life."