Some bodybuilders use drugs such as anabolic steroids and precursor substances such as prohormones to increase muscle hypertrophy. Anabolic steroids cause hypertrophy of both types (I and II) of muscle fibers, likely caused by an increased synthesis of muscle proteins. They also provoke undesired side effects including hepatotoxicity, gynecomastia, acne, the early onset of male pattern baldness and a decline in the body's own testosterone production, which can cause testicular atrophy.[43][44][45] Other performance-enhancing substances used by competitive bodybuilders include human growth hormone (HGH), which can cause acromegaly.
^ Mangano, Kelsey M.; Sahni, Shivani; Kiel, Douglas P.; Tucker, Katherine L.; Dufour, Alyssa B.; Hannan, Marian T. (February 8, 2017). "Dietary protein is associated with musculoskeletal health independently of dietary pattern: the Framingham Third Generation Study". The American Journal of Clinical Nutrition. 105 (3): 714–722. doi:10.3945/ajcn.116.136762. PMC 5320406. PMID 28179224 – via ajcn.nutrition.org.
The motor proteins actin and myosin generate the forces exerted by contracting muscles. Current recommendations suggest that bodybuilders should consume 25–30% of protein per total calorie intake to further their goal of maintaining and improving their body composition.[30] This is a widely debated topic, with many arguing that 1 gram of protein per pound of body weight per day is ideal, some suggesting that less is sufficient, while others recommending 1.5, 2, or more.[31] It is believed that protein needs to be consumed frequently throughout the day, especially during/after a workout, and before sleep.[32] There is also some debate concerning the best type of protein to take. Chicken, turkey, beef, pork, fish, eggs and dairy foods are high in protein, as are some nuts, seeds, beans, and lentils. Casein or whey are often used to supplement the diet with additional protein. Whey protein is the type of protein contained in many popular brands of protein supplements and is preferred by many bodybuilders because of its high Biological Value (BV) and quick absorption rates. Whey protein also has a bigger effect than casein on insulin levels, triggering about double the amount of insulin release.[33] That effect is somewhat overcome by combining casein and whey. Bodybuilders are usually thought to require protein with a higher BV than that of soy, which is additionally avoided due to its claimed estrogenic properties. Still, some nutrition experts believe that soy, flax seeds and many other plants that contain the weak estrogen-like compounds or phytoestrogens, can be used beneficially, as phytoestrogens compete with estrogens for receptor sites in the male body and can block its actions. This can also include some inhibition of pituitary functions while stimulating the P450 system (the system that eliminates hormones, drugs and metabolic waste product from the body) in the liver to more actively process and excrete excess estrogen.[34][35] Cortisol decreases amino acid uptake by muscle, and inhibits protein synthesis.[36]

An article by Muscle & Fitness magazine, "Overtrain for Big Gains", claimed that overtraining for a brief period can be beneficial. Overtraining can be used advantageously, as when a bodybuilder is purposely overtrained for a brief period of time to super compensate during a regeneration phase. These are known as "shock micro-cycles" and were a key training technique used by Soviet athletes.[54]
Due to the growing concerns of the high cost, health consequences, and illegal nature of some steroids, many organizations have formed in response and have deemed themselves "natural" bodybuilding competitions. In addition to the concerns noted, many promoters of bodybuilding have sought to shed the "freakish" perception that the general public has of bodybuilding and have successfully introduced a more mainstream audience to the sport of bodybuilding by including competitors whose physiques appear much more attainable and realistic.
Comer has an athletic build that comes from years of martial arts and marathon training, not to mention amateur competitive bodybuilding, activities that have taken a toll on her now bandaged 40-something-year-old knees. — Quanta Magazine, "The Art of Teaching Math and Science," 16 June 2019 Teresa Giudice, who's best known as a personality on Bravo's Real Housewives of New Jersey, competed in her first bodybuilding contest Saturday. — Carly Mallenbaum, USA TODAY, "'Real Housewives' star Teresa Giudice shows off new muscles at bodybuilding competition," 10 June 2018 His first wife, Sitora Yusufiy, suggested in an interview with Time magazine, with little evidence other than his penchant for bodybuilding and mirror-gazing, that Omar Mateen could have been gay. — Tim Fitzsimons /, NBC News, "What really happened that night at Pulse," 12 June 2018 The physique competition will be held at McGlohon Theater and includes the following categories: bodybuilding, fitness, men’s physique, figure, bikini, classic physique and women’s physique. — Courtney Devores, charlotteobserver, "Your 5-minute guide to the best things to do in Charlotte | June 22-28," 21 June 2018 Fans who have been following Giudice closely on social media have watched the reality star workout in videos, but Giudice hasn't posted publicly about her first bodybuilding competition. — Carly Mallenbaum, USA TODAY, "'Real Housewives' star Teresa Giudice shows off new muscles at bodybuilding competition," 10 June 2018 Carolyn Marvin, who served as the graduate adviser for both Prosper and Nirenberg, pointed to his thesis, an autoethnography about the subculture of bodybuilding. — Josh Baugh, San Antonio Express-News, "Nirenberg knew immediately that he’d eventually marry Erika Prosper," 17 Mar. 2018 The bodybuilding competition is one of two hosted produced each year in Louisville by Kentucky Muscle promoter Brent L. Jones. — Matt Stone, The Courier-Journal, "Bodybuilders, fitness athletes go flex at 2018 KDF Derby Championships," 29 Apr. 2018 Father John Brown is basically a bodybuilding legend, having won two Mr. Universe titles and three Mr. World crowns. — Jr Radcliffe, Milwaukee Journal Sentinel, "Facts you may have missed about each Packers draft choice in 2018," 4 May 2018
The winner of the annual IFBB Mr. Olympia contest is generally recognized as the world's top male professional bodybuilder. Since 1950, the NABBA Universe Championships have been considered the top amateur bodybuilding contests, with notable winners such as Reg Park, Lee Priest, Steve Reeves, and Arnold Schwarzenegger. Winners generally go on to become professional athletes.
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