Connie Weaver, PhD, Distinguished Professor of Food and Nutrition at Purdue University, reported in her Jan. 2002 presentation at the Calcium Summit II conference titled "Bone Health Hazards: The Make-It-Or-Break-It Teenage Years":

“Adolescence is a critical time to optimize bone health, given that approximately 50% of skeletal mass is accrued during adolescent years. In girls, 95% of total body mineral mass is accumulated by age 17 and 99% by age 27. Optimizing bone health during adolescence not only reduces future risk of osteoporosis, but also helps to prevent forearm fractures during youth…

Findings from ongoing studies indicate that four to five servings/day of calcium-rich foods such as milk and other dairy products are needed to optimize peak bone mass during adolescence. Osteoporosis is a pediatric disease with geriatric consequences. With low calcium intake levels during important bone growth periods, today’s youth faces a serious public health problem in the future.”

Jan. 2002