Jennifer Hudson has lost a TON of weight since her days on "American Idol" . . . and obviously, she's proud of that.

But check this out: She tells "Self" magazine, "I'm prouder of my weight loss than my Oscar." Jennifer won Best Supporting Actress for "Dreamgirls"in 2007.

Before she was famous, Jennifer was a size 16 . . . and she thought she was, quote, "the perfect size." But obviously, that changed.

She says, "I didn't even know I was considered plus-sized until I came to Hollywood . . . An interviewer asked, 'How does it feel to be plus-sized in Hollywood?'

"I looked around, like, Who is she talking to? Oh, me? I'm plus-sized? In the neighborhood I'm from in Chicago, a 16 is normal. But in Hollywood, everyone looks exactly the same, so I stood out."

Jennifer decided to lose weight while she was pregnant with her son, who's 2 now. She says, quote, "I thought, hold on . . . why doesn't anybody know I'm pregnant? And I wanted to set a good example for my son."