Betty Brosmer (born August 2, 1935), later known by her married name Betty Weider, is an American bodybuilder and physical fitness expert. During the 1950s, she was a popular commercial model and pin-up girl. After marrying entrepreneur Joe Weider in 1961, she began a lengthy career as a spokesperson and trainer in the health and bodybuilding movements. She has been a longtime magazine columnist and co-authored several books on fitness and physical exercise.
Betty Brosmer was born in Pasadena, California, on August 2, 1935, to Andy and Vendla Brosmer. Her first name has sometimes been reported as Elizabeth, but she has stated that this is incorrect.
She lived her early childhood in Carmel but later, from about the age of ten, grew up in Los Angeles. Naturally small and slight of frame, Brosmer embarked on a personal bodybuilding and weight training regimen before she was a teenager. Raised as a sports fan by her father, she excelled in youth athletics and was "something of a tomboy".