A "natural bodybuilder" refers to someone who builds and develops their muscles through exercise and proper nutrition without the use of any performance-enhancing substances or drugs.
Instead I spent some time researching and taking notes from natural bodybuilders who already had the physique that I wanted and applied all their techniques in my training sessions and diet. (justinkavanaghfitness.com)
One thing that a lot of natural bodybuilders lack is leg development. (hugorivera.net)