Understanding your teenager's nutritional needs - and why they differ for girls and boys
Adolescence is one of the most nutritionally demanding periods of our lives - and yet it's precisely when teenagers start making their own food choices, driven by independence, peer pressure, and a very normal desire to do things their own way.
The growth, hormonal shifts and brain development happening during puberty place enormous demands on the body, but do our teenagers have the nutrients to fuel all of this change?
As a nutritionist, I am acutely aware of the impact of nutrient deficiencies at this stage of life - but as a mum, I also know that my ability to influence my kids' day-to-day food choices is rapidly diminishing. As they've become more independent, I've made peace with focusing on nourishing them well when they are home. But even that can be a challenge when you're dealing with a picky eater who has very strong opinions about what they will and won't put in their mouth.
Anyway - enough about my mealtime chaos. Here's what's actually happening in your teenager's body, and why it matters more than most people realise.
Why puberty dramatically increases nutritional demands
The speed at which teenagers can grow during puberty is quite astounding. My youngest grew 10 centimetres in 12 months last year. If you have children of both sexes, you would have noticed that girls tend to experience their growth spurts earlier than boys - often a couple of years ahead - so their nutritional demands can increase at quite different times to their brothers. Either way, this type of growth requires significantly more calcium, phosphorus and vitamin D to support rapid bone mineralisation.
Hormonal shifts increase the body's demand for micronutrients involved in hormone production, cellular repair, and energy metabolism, meaning the same diet that worked at age 9 is genuinely insufficient by age 13. The brain is also undergoing major remodelling during adolescence, particularly in the areas responsible for decision-making and emotional regulation, making adequate nutrition during this window more important than most people realise.
Girls: the iron-mood-energy connection and why periods change everything
Once menstruation begins, girls lose iron every month, and it's often the last thing parents think to consider when their daughter seems tired, flat or emotionally overwhelmed. Because iron is essential for dopamine and serotonin synthesis, chronically low levels can look a lot like depression or anxiety in teenage girls, making it one of the first things worth ruling out if your daughter is struggling with her mental health.
To compound the problem - and something I have experienced firsthand - many teenage girls decide to reduce their red meat intake (or go vegetarian) at exactly the moment their iron needs increase.
Girls: Zinc, magnesium and B vitamins and the link to mood and stress resilience
Zinc, magnesium, and B vitamins are critical for teenage girls' mental and emotional wellbeing. All three play a direct role in neurotransmitter production, stress regulation and mood stability, but unfortunately they are commonly depleted in diets high in processed foods.
Zinc and magnesium are also both depleted by stress itself, creating a frustrating cycle — stressed teenagers eating poorly become even less equipped to handle stress, which then affects everything from sleep quality and concentration to emotional resilience and skin health. Magnesium is also particularly beneficial for girls post-puberty because of its role in reducing PMS symptoms. Many teenage girls experience symptoms like cramping, irritability, low mood and disrupted sleep in the lead-up to their period, all of which can be meaningfully improved with adequate magnesium intake.
B vitamins (particularly B6, folate and B12) are essential for methylation and the production of serotonin and dopamine. Deficiencies are especially common in girls on restrictive or highly processed diets and this can contribute to mood swings, poor sleep and difficulty managing everyday pressures.
The frustrating reality is that these three nutrients are all depleted by the very things that come with the territory in the teenage years - stress, poor sleep and a diet that leans heavily on convenience food and sugar.
Boys: Protein, zinc and magnesium for rapid muscle and bone growth
Puberty triggers a surge in testosterone that drives rapid muscle development, and the protein requirements that come with it are higher than most people realise. My son would roll his eyes if he knew I was writing this (I may have mentioned it a few times), but the truth is that many active teenage boys are simply not eating enough protein to keep up with what their body is trying to do, and it's worth paying attention to.
Zinc is directly involved in testosterone metabolism and is lost through sweat, meaning physically active boys can become depleted quickly, leading to symptoms like slow recovery, poor concentration and delayed growth. Zinc is also worth mentioning for its role in skin health and treating acne, as it has well-established anti-inflammatory properties and helps regulate sebum production.
Magnesium supports muscle function, sleep quality and bone density - all critical areas during a growth spurt - but it is one of the most commonly deficient minerals in diets heavy in processed and fast food.
Why the average teenage diet often falls short
The modern teenage diet tends to be sufficient in calories but lacking the vitamins and minerals that actually matter most during this phase of life.
Eating a diet heavy in ultra-processed foods displaces the type of nourishing whole foods that provide the concentrated micronutrients puberty demands, and to make matters worse, some ingredients in processed foods actively interfere with nutrient absorption.
Social eating, busy schedules and increasing autonomy over food choices all make it harder for teens to eat in a way that matches their biological needs. And don’t get me started on school canteens (that’s one for another post…).
Should you consider supplements?
Even with a good diet, some teenagers may need additional support during periods of rapid growth, high stress or heavy periods. Iron and zinc are the most commonly deficient nutrients in teens and are worth testing if your child is showing signs of low mood, fatigue, poor immunity or difficulty concentrating. Magnesium is also worth considering for teenagers who struggle with sleep, anxiety or muscle cramps. Always work with a qualified practitioner before supplementing, as getting the dose and form right matters.
Food first — the best sources of these key nutrients
While supplements can play a useful role, food should always be the foundation. Here are some of the best dietary sources of the nutrients we've covered:
Iron: Red meat, lamb, chicken liver, canned fish, eggs, legumes, tofu, spinach, pumpkin seeds. Pair plant-based iron sources with vitamin C (e.g. lemon juice, capsicum or kiwi fruit) to improve absorption.
Zinc: Red meat, shellfish (especially oysters), chicken, pumpkin seeds, legumes, nuts and wholegrains.
Magnesium: Dark leafy greens, nuts and seeds (especially almonds and pumpkin seeds), dark chocolate, avocado, legumes, wholegrains and bananas.
B vitamins: Meat, eggs, dairy, leafy greens, legumes and wholegrains. B12 is found almost exclusively in animal products, so vegetarian and vegan teenagers may need to supplement.
Protein: Meat, poultry, fish, eggs, dairy, legumes, tofu and tempeh. Aim for a quality protein source at each meal - and preferably snacks too.
Calcium and vitamin D: Calcium is found in dairy products, fortified plant milks, canned fish with bones, leafy greens and tofu. Vitamin D is primarily obtained through sun exposure, with small amounts found in oily fish and eggs.
How to support your teenager practically — without turning food into a battleground
Here are a few things that have worked for me personally, and that I recommend to parents in my clinic:
Focus on adding in nourishing foods, rather than restriction. It can also be helpful to frame conversations about food choices around energy, skin, mood and performance (things they care about) rather than abstract discussions about health or weight.
Keep the fridge and pantry stocked with easy, nutrient-dense options for when teens are hungry between meals, e.g. boiled eggs, nuts, shredded chicken breast, cooked meatballs, bliss balls, fruit, yoghurt
Avoid making individual meals a point of conflict. The overall pattern matters far more than any single food choice, and preserving a positive relationship with food and family meals has long-term value that outweighs any short-term nutritional win
References
Das, J., Salam, R., Thornburg, K., Prentice, A., Campisi, S., Lassi, Z., Koletzko, B., & Bhutta, Z. (2017). Nutrition in adolescents: physiology, metabolism, and nutritional needs. Annals of the New York Academy of Sciences, 1393.
Parajuli, J., & Prangthip, P. (2025). Adolescent Nutrition and Health: a Critical Period for Nutritional Intervention to Prevent Long Term Health Consequences. Current Nutrition Reports, vol. 14, no. 1, 116.
Soliman, A., De Sanctis, V., & Elalaily, R. (2014). Nutrition and pubertal development. Indian Journal of Endocrinology and Metabolism, 18, pp.39 - 47.
Wahl, R. (1999). Nutrition in the adolescent.. Pediatric annals, vol.. 28, no. 2, pp.107-11.