Sunisa Lee, the all-around gold medalist in women’s gymnastics at the Tokyo Olympics, woke up one morning last year and was startled by her reflection in the mirror.

Her face looked as if it had been inflated with an air pump. Her leg joints were so swollen that she could hardly bend her knees or ankles. A scale revealed she had gained more than 10 pounds.

Her mind raced: Had she been eating too much? Was it the pollen in the air? Maybe she was allergic to her roommate’s new dog?

“I was like, who is this person looking back at me?” Lee, who is competing for the United States at the Paris Games, said in an interview. “It was so scary. I didn’t know it then, but the old Suni was gone. And she would never be back.”

Lee had been a surprise winner in Tokyo: Simone Biles — the overwhelming favorite for that gold medal — had withdrawn from the Games with a mental block that made her feel unsafe performing her flips and twists in the air.

The title of gold medalist came with a level of celebrity that Lee, who was a quiet 18-year-old from a conservative Hmong community in Minnesota, was not prepared for — and didn’t want.