Last year, she got laproscopic bariatric surgery after she and her older brother were diagnosed with Type 2 diabetes.
Sidibe said, "I truly didn't want to worry about all the effects that go along with diabetes. I genuinely [would] worry all the time about losing my toes."
You can read more about her transformation in her memoir, This Is Just My Face: Try Not to Stare.
Good for her. I wish she was styled better on Empire like she is in the source's right photo.