The sport of bodybuilding is based on drug use. No drugs equal no sport. Bodybuilding magazines wouldn't exist because they couldn't use steroid guys as their example of their supplements. There would be a few contests held mainly in high school auditoriums. The sport might have had a name change from bodybuilding to physical culture. Training the heart muscle would be just as important as bicep training. Guy doing bodybuilding would actually be used as an example of a healthy activity. Imagine lifting and doing cardio without drugs? It would held in such high regard for it's health benefits.
Sports would still exist with the same popularity. Football, baseball, olympic lifting, wrestling, boxing and all the rest would still be here. In football the front line would be about 265 to 275lbs instead of the universal 300lbs plus line. The sport would be just as exciting. Instead of approaching the 600lbs barrier in the clean and jerk it would be the 500lbs barrier.