When pressed for simple solutions to drastic, lasting body transformations, most experts will tell you there are none—that no single workout, diet, or supplement will help you pack on heaps of lean, clean muscle. They’d be right. There isn’t one route to a new physique. There are many.

Once you accept this concept, it’s time to start narrowing your focus. One approach is to scour journals for methods that are known to work in the sterile construct of the lab. The other, better solution would be to take cues from methodologies that have been tested—and decisively proven—in the testing grounds of the kitchen and the gym.

No offense to the experts in lab coats, but the best solutions are always evident in the physiques they produce. Here are some of the transformative lessons learned from people who have gone through dramatic before-and-afters.