that's right - two turkeys

One side effect of the obesity epidemic in America is rarely noted: Women's chests are expanding nearly as fast as their bellies. Poor eating habits, as well as breast implants and the estrogens in birth-control pills, have led to an increase in the past 15 years of more than one bra size for the average American woman—from a 34B to a 36C. For many women, this has been a burdensome trend. A pair of D-cup breasts weighs between 15 and 23 pounds—the equivalent of carrying around two small turkeys. The larger the breasts, the more they move and the greater the discomfort. In one study, 56 percent of women suffered from breast pain when jogging.


http://discovermagazine.com/2005/nov/physics-of-bras/