Final answer:
The claim that bone density should be about 20% of total body weight is false. Bone density refers to the mineral content of the bones, which is not the same as bone weight percentage. Exercise and hormones like estrogen can affect bone density.
Step-by-step explanation:
The statement that one wants bone density to be about 20% of total body weight is false. Bone density is a measure of the amount of calcium and other minerals in the bones. Although it is important for bones to be dense enough to be strong and support the body, they do not make up 20% of a person's total body weight. The optimal fat content for females is mentioned as between 20, but this is different from bone density. Bone mass peaks around the age of 30 and then declines as a person ages, with women typically losing bone mass more rapidly than men.
Building sufficient bone mass in the young adult years is crucial because it sets up the foundation for bone health in later life. Factors that affect bone density include exercise, particularly resistance training which can stimulate the deposition of more bone tissue, and other factors like nutrition and hormonal levels. Notably, estrogen is said to promote the production of new bone, providing a connection between hormone levels and bone density.