Growing into her biggest film role

Sarah Steele has a “huge” problem performing a script “I don’t believe would happen. As an actress it’s very crucial that I actually believe that a character exists.”

So the 16-year-old actress, a junior at a private Philadelphia high school, “definitely had my doubts about myself as an actress. Then honestly, with just sheer dumb luck, I got this.”

“This” is the role of Bernice, the sweet, overweight daughter of Tea Leoni and Adam Sandler in James L. Brooks’ comedy-drama “Spanglish.” Steele brings poignancy to her role, especially in her touching scenes with a subdued Sandler. In his “Spanglish” review, The Times’ Kenneth Turan describes her performance as “truly winning.”

She had to super-size herself to play Bernice. At just 5 feet tall, the petite Steele fluctuates between a size 1 and 2. “I gained probably 15 to 17 pounds,” she says. “And then I had my fat suit. It was cotton and spandex. It was pretty comfortable.”

Though her father is a doctor who specializes in diet and nutrition, Steele didn’t go on a special diet. She bulked up on McDonald’s. And she had no problem maintaining her weight.

“The food on set was amazing,” she says, laughing. “I was the only actress who could eat it. Everyone else sort of watched their weight.”

Steele says she felt it was her duty to do justice to Bernice because few films explore teenage obesity problems.

“You just see all of these movies where the kids are thin, blond and gorgeous and perfect. People can’t relate to that. Sometimes I would just put on the fat suit and walk around and people do look at you differently.”

She credits Sandler for making her feel comfortable on the set. “Between scenes and stuff he would sit around and talk to me about his high school experience. I honestly felt like I was right back in high school. He made me laugh.”