According to the American Cancer Society, any weight between 107 and 131 pounds is within the healthy body mass index range for someone that stands 5 foot 3 inches tall. While the BMI scale is useful for looking at the weight distributions for populations, most experts agree that it is not perfect for determining the healthiest weight for an individual.
Although body mass index is a good general guideline, different individuals can be healthy at body mass indexes outside of the generally accepted range. The most common exceptions to the BMI scale are people with considerable muscle mass. Many professional bodybuilders are very healthy because they exercise frequently and carry very little body fat, but they are very frequently considered to be obese on the BMI scale.