Could a healthy lifestyle give 50-year-old woman the body of 20-year-old woman?

No, a healthy lifestyle cannot give a 50-year-old woman the body of a 20-year-old woman. The aging process involves natural changes in the body, including a decrease in muscle mass and an increase in body fat, which cannot be completely reversed through a healthy lifestyle alone. Additionally, there are genetic and hormonal factors that contribute to the differences in body composition between individuals of different ages.