Weight gain for teens and athletes
When a teen is genuinely underweight, growing through a spurt, or trying to fuel for sport. Calories without compromising the relationship with food.
Why teens can struggle to gain weight
Growth spurts, high activity levels (sport, school commute, restless metabolism), inadequate intake, or sometimes an underlying issue like coeliac disease, IBD, thyroid problems, or a developing eating disorder. Conditions like coeliac disease and IBD need ruling out. The cause shapes the plan entirely, which is why assessment comes before advice.
Some teens genuinely struggle to eat enough to keep up with their growth and activity demands. The energy demands of a rapidly growing, active teenage boy can be surprisingly high, and that's a lot of food for a teenager to fit in. Others may be eating what seems like enough but have an underlying condition affecting absorption or increasing metabolic demands.
The first step is always working out why the weight gain isn't happening. Is it inadequate intake? Poor appetite? Malabsorption? An eating disorder? Activity demands outstripping intake? Each of these has a different solution, and getting it wrong wastes time and can cause harm.
Practical strategies for
Once we know the cause, the approach is usually about increasing calorie density without dramatically increasing food volume. Most underweight teens aren't going to suddenly start eating twice as much. Calorie density can be increased through practical changes to existing meals, tailored to what your teen eats. The specifics are worked out in a consultation.
Timing and distribution of eating matters and is tailored individually. For teen athletes, nutrition around training is a specific skill that supports both performance and weight gain, and is covered in a consultation.
Weight gain for
Teen athletes often need significantly more energy than their non-athletic peers, and the culture around sport can complicate things. Some sports emphasise leanness, some emphasise bulk, and teens can get caught up in body composition goals that aren't appropriate for their age or stage of development.
My approach with teen athletes focuses on fuelling for performance and recovery rather than chasing a specific body composition. Adequate carbohydrates around training (this is the bigger lever than most teens realise), enough protein spread across the day, and overall calorie adequacy. Specific sports nutrition advice from someone who works with young athletes matters here, because adult sports nutrition advice doesn't always translate well to growing bodies.
Protein supplements and shakes have a limited role. Most teen athletes can meet their protein needs through food. Where supplements come in is convenience, not necessity, and they should never replace meals. Creatine and other performance supplements are generally not recommended for under-18s, a position supported by the BDA.
When weight loss in a teen is
Unexplained weight loss in a teenager always deserves investigation. Possible causes that need medical investigation include coeliac disease, inflammatory bowel disease, hyperthyroidism, diabetes, chronic infection, and eating disorders. The NHS advises that unexplained weight loss always warrants medical review. Sometimes it's simply that intake hasn't kept up with a growth spurt, but that's a diagnosis of exclusion.
Particular red flags: weight loss with fatigue, abdominal symptoms, changes in bowel habit, excessive exercise, food avoidance, secrecy around eating, or a sudden interest in 'clean eating' or dietary restriction. If any of these are present alongside weight loss, assessment is important and should be sought promptly.
Common questions
A clear plan,
built around your little one.
All consultations are online and you can self-refer directly. You'll receive a written plan after every appointment.
Thorough assessment & plan
Your first appointment is 60 minutes. It includes a full clinical and dietetic assessment, and you'll receive an agreed, written plan to take away.
Review & adjust
Follow-ups are 30 minutes. We review the plan, problem-solve anything that's come up, and adjust guidance as your child progresses.
Currently self-pay only. All fees are VAT-exempt as registered healthcare services. I provide receipts with my HCPC registration details which you can submit to your insurer.