Watch The Key to Beauty (1917) : Full Movie Online Free A lot has changed in the years since this promotional short film was made—but a lot hasn’t. Gym clothes have certainly improved, and exercise equipment is sleek and modern. But the message this film sends—“Ladies, the key to beauty is to be fit and be thin”—is still prevalent in 21st-century American society. The various exercises demonstrated here are designed to improve one’s health, posture, muscle tone, and according to the filmmakers, bring happiness.