Nutrition for Active Teens - What Trainers Need to Know

Nutrition for Active Teens-What Youth Trainers Need to Know

More and more teens are working with professional trainers. Many are athletes looking to stay in shape or improve skills in the off season. Others just want to get fitter and some may also struggle with diet and weight. 

Regardless of why they come to you, providing nutrition advice is a great extra service you can offer—as long as you stay within your scope of practice. Teenagers don’t always make the best food choices, and as a trainer they respect you. It’s a great opportunity for education. 

Teach your teenage clients how to eat well, how to fuel the body for activities, when not to worry about weight, and how to avoid pitfalls like disordered eating. Always work with your clients and their parents together on this topic and refer them to a registered dietician or even a physician if you feel they need more assistance than your expertise can provide.

Nutrition for Active Teens – Calorie Intake

Generally, it is not necessary for teens to count calories. Unless there is an issue, such as not eating enough or overeating and gaining too much weight, it’s more positive and effective to focus on nutrients and a balanced diet. But here are some general guidelines for the number of calories teens should be consuming per day:

  • Moderately active boys, 14 to 18 – 1700 to 2000
  • Active boys, 14 to 18 – 2800 to 3200, or more
  • Moderately active girls, 14 to 18 – 2400 to 1800
  • Active girls, 14 to 18 – 2200 to 2400, or more

Focusing on Macronutrients and Food Choices

It’s a good idea to understand generally how many calories active and athletic teens need each day, but focusing on calorie counting is not the most effective strategy for teaching positive, healthy eating habits. Instead, focus your teen clients on choosing the right foods in the right proportions. 


Protein is essential for building muscle as well as for healthy hair, nails, and skin. For young athletes, at least ten to 30 percent of their daily calories should come from protein.1 This is probably not a big issue for your clients, as most American teens eat diets with plenty of protein. Meat, dairy, fish, poultry, eggs, beans, tofu, and other meat-substitute products are good sources of protein.


An active teen should include carbs as 40 to 60 percent of their daily calorie intake.1 Carbohydrates are essential for fueling the active body. They provide the glucose that fuels daily living and sports. Because it is typical in today’s food and health culture to demonize carbs, it is important to teach active teens about their necessity. They can get carbs from whole grains, beans, starchy vegetables, and dairy. 


Fat also tends to be demonized, but active teens should be getting about 25 to 35 percent of their daily calories from this macronutrient.1 Fat is necessary for absorbing and using certain vitamins, for energy, for a feeling of satiety, and for protecting vital organs. Healthy sources of fat for teens include lean meats and fish, dairy, olive oil, and nuts and nut butters. They should avoid processed foods high in fat. 

Brush up on your macro knowledge with this overview guide from the ISSA blog


There are many micronutrients—vitamins and minerals—that active teens need. However, there are a few to focus on with your clients:

  • Vitamin D is essential for good bone health and absorption of calcium. Athletes, in particular, need strong bones to avoid breaks and injuries. Teens who largely train indoors should be especially aware of vitamin D, which we metabolize through sun exposure. All active teens should eat foods fortified with the vitamin, like dairy or tofu. 
  • Calcium is similarly important for bone strength and can be found in dairy products and fortified grains. It is also high in certain vegetables, like broccoli and spinach. 
  • Iron is necessary for delivering oxygen throughout the body, an essential part of energy production. Growing and active teens need more iron than people at other ages. Meat, eggs, leafy greens, and fortified grains are rich in iron. Vegetarian or vegan teens should be particularly aware of iron and may need a supplement. 

Meal Planning and Filling the Plate

Not many teens are prepared to count their macros, so make it simple for them. The plate method is one way to help teens understand how to balance their foods and macronutrients:

  • A balanced meal is like a plate. 
  • One half of that plate should be filled with a variety of non-starchy vegetables like broccoli, peppers, tomatoes, and greens. 
  • One quarter of the plate should be protein, which could include chicken, beef, fish, eggs, or a vegan protein like tofu. 
  • The final quarter of the plate should be half fats, like nuts, seeds, or oil, and half grains and starches, including rice, potatoes, or bread. 
  • Fruits can be included too, but should be considered an extra on the side, used for a dessert or a recovery food after practice or a game. 

Eating for Sports

Whether your teen clients are school athletes or just like to workout, help them understand how to eat and hydrate before, during, and after their most active periods. 

Nutrition Before Activities

Help your teen athletes design a few different options for pre-game or pre-workout meals. They should aim for a small meal with both protein and carbs two to four hours in advance. Avoid too much fat and eating in the hour before being vigorously active. 

Eating While Active

For activities going on for an hour or more, it’s a good idea for your teen athletes to fuel up during events or workouts. Small, easy-to-digest, and carb-centric snacks are best: sports drinks, an orange or a banana, or a few crackers. 


It’s essential for any athlete to be hydrated leading up to an athletic event and to hydrate during and after as well. Sports drinks aren’t strictly necessary unless your teens are active for more than an hour and don’t have any other snacks to refuel. Otherwise, water is just fine. Here are some hydration guidelines for teens2:

  • Drink 400 to 600 mL of water two to three hours before an event. 
  • Consume between 150 and 300 mL every 15 or 20 minutes during activities. 
  • Drink 150 to 250 mL of water after a game or workout. 

Show your teen clients this comprehensive hydration guide to help them better understand the importance of water. 

Recovery Nutrition for Active Teens 

Encourage your teen clients to eat a small snack about 30 minutes after activities and again after an hour or two. They need carbs to replenish their glycogen stores, so suggest whole pieces of fruit. Protein is important too, and a later snack of toast and peanut butter is a good option.

Disordered Eating

When working with any client, but especially with teens who may be more vulnerable to it, always watch for signs of disordered eating:

  • Eating too much or too little, or, in other words, frequently eating in a way that doesn’t match physiological need
  • Any kind of eating habits that impair physical or psychological health, like extreme guilt after eating too much in one sitting
  • An obsession with food and eating
  • Eating behaviors that either cause distress or are used in order to try to relieve distress, such as bingeing when sad or depressed

Disordered eating is very dangerous, especially for teens whose brains and bodies are still developing. Your guidance now could prevent these behaviors but you should always be cautious and aware of disordered eating when working with young clients. If you see problematic behaviors talk to the parents and refer them to a specialist. 

Working with teen athletes can be rewarding. You have a great opportunity to teach them lifelong skills for staying fit and meeting athletic goals but also for eating well and making positive food choices. 

To be better qualified to counsel your clients on nutrition decisions, check out the ISSA’s course for becoming a Certified Nutrition Coach



1. Purcell, L.K. (2013, April). Sport Nutrition for Young Athletes. Pediatr. Child. Health. 18(4), 200-202. Retrieved from

2. Sawka, M.N., Burke, L.M., Eichner E.R., Maughan, R.J., Montain, S.J., and Stachenfeld, N.S. (2007, February). American College of Sports Medicine Position Stand. Exercise and Fluid Replacement. Med. Sci. Sports. Exerc. 39(2), 377-90. Retrieved from