Teenagers embrace 'cut and bulk' regimes as muscle culture spreads online

A growing number of teenagers are adopting "cut and bulk" cycles and other intense gym practices to achieve highly defined, muscular physiques, a trend driven largely by social media and raising concerns among health professionals about potential impacts on growth, hormones and eating disorders.

The cut-and-bulk approach involves deliberately eating hundreds of calories above maintenance for weeks to build muscle mass, then sharply reducing calories to lose fat and reveal muscle definition. Content promoting sculpted torsos and gym techniques has proliferated on platforms such as TikTok; posts under hashtags like #shreddedphysique have been viewed more than four billion times. For some adolescents that means occasional training and higher-protein meals; for others it has become a near-daily regime of heavy lifting, close calorie counting and restrictive eating patterns.

Fourteen-year-old bodybuilder George Holland began using a gym at age 11 after watching online videos and has since competed in junior national events. He won a bronze medal in the under-19 category at the National Amateur Body-Builders' Association finals and said he now trains with a former Mr Universe, bench-pressing 140kg, squatting 180kg and deadlifting 200kg. George said he eats six meals a day, posts to his combined 140,000 TikTok and Instagram followers and is currently in a bulking phase consuming about 4,100 calories a day; he expects to cut his intake to around 2,200 calories during a later phase.

George told a BBC reporter that he disagrees with suggestions teenagers should avoid the gym. "Going to the gym when you are young is dead good for you. It's good for your mental health, your overall fitness, and it gives you good discipline," he said, describing training and discipline as positive influences.

Other young gym-goers describe different pathways into the trend. George Hazard, now 17, began working out at 12 with a modest home setup during the COVID-19 lockdown. He said training five or six nights a week helped his mobility after a childhood leg-lengthening operation. Hazard said he and peers often learn techniques and regimes from social media and use study links attached to posts to judge credibility, but he acknowledged challenges in following strict diets while living at home.

Eighteen-year-old Nat Walney said he experimented with "dirty bulking" in his mid-teens by consuming large amounts of processed food to gain size, then shifted to more extreme diets including a self-directed carnivore and fasting regimen. Nat said he fasts for 20 hours daily and eats mainly raw meat, eggs and raw milk, and that he has used AI tools such as ChatGPT to help design parts of his regime. He acknowledged family concerns about the approach and said he would change course if it affected his health.

Health professionals and youth sports coaches say the desire to be fit is not inherently problematic, but that extremes can be harmful to adolescents whose bodies are still growing. Children's dietitian Lucy Upton said social media content can sometimes "nod to a scientific truth" while presenting it out of context and urged teens and parents to assess whether health advice comes from a clinical background or personal experience. She added that endorsements tied to product sales are a red flag.

Sam Grady-Graham, a GB Boxing coach, warned that restrictive diets in the teenage years can jeopardise growth because the rate of physical development between about 12 and 18 is rapid and requires balanced nutrition. "Movement over muscle is the way we look at it," he said, advising young athletes to prioritise technique and a broad range of movement rather than immediate heavy loading.

Experts also raised concerns about specific practices seen among some adolescents. Prolonged caloric restriction and extreme fasting can impair organ function and hormonal development, dietitians say, and patterns of behaviour focused on achieving an idealised muscular appearance can feed muscle dysmorphia — a condition in which individuals perceive themselves as inadequate despite muscularity — and broader disordered eating. Sports nutritionists caution that frequent cycles of overeating and strict cutting can affect hormone health and normal growth trajectories.

Use of AI chatbots for diet and training advice is increasingly common among young people but comes with caveats. Information from such tools varies in quality and may lack clinical evidence; clinicians recommend seeking guidance from registered dietitians, paediatricians or qualified sports medicine professionals when making decisions that affect adolescent growth and health.

Parents, coaches and health practitioners who work with teenagers said open conversations about goals, evidence-based guidance and the physical and psychological risks of extreme regimes are important. While the popularity of gyms and interest in strength training can support physical activity, professionals emphasise that healthy adolescent development typically depends on balanced diets from all food groups, appropriate training loads, attention to movement quality, and monitoring for signs of harm rather than pursuing a single idealised body image.

Public-health specialists say the growing visibility of teenage muscle culture underscores the need for clearer, accessible guidance for young people on safe training, nutrition and mental-health risks. Coaches and clinicians recommend that adolescents seeking to improve strength and fitness work with qualified adults, focus on gradual progression and consume a balanced diet to support both exercise and normal physical development.