Can body improvement turn bad? As a teenage bodybuilding craze sweeps social media, some celebrate young people getting in shape. But for a few, it becomes a dangerous obsession.
Experts warn over ‘gains’ obsession
Gym bro culture: Many people are familiar with the idea that social media can affect girls' body image, but there is less research on how gymfluencers may be affecting boys. Glossary
Bodybuilder - A person who does regular exercise in order to make their muscles look bigger.
Obesity - The medical condition of being very overweight. There are many ways of measuring this, including a BMI of 30 or more. (You can work out your BMI by dividing your weight in kilograms by your height in metres squared.)
Self-esteem - Belief and confidence in your own value and abilities.
Muscle dysmorphia - A subtype of body dysmorphic disorder. It is the delusional or exaggerated belief that one's own body is not muscular enough.
Dietician - Qualified health professionals who treat dietary and nutrition problems. They are regulated by law.
Eating disorders - A range of mental health conditions which result in somebody having abnormal eating patterns, which then affects their physical and mental health.
Fatigue - Tiredness.
Depression - Low mood that affects someone's daily life, and can last for weeks or months.
Paediatrician - A doctor who works with children.
GB - Great Britain