Researchers recommend a few extra snacks: Not all young athletes manage to eat enough

Growing adolescents who train heavily often do not understand how much food they need.

This is explained by clinical nutritionist Anu Koivisto-Mørk at the Sports Health Centre.

As part of her PhD at the University of Oslo, she has researched diet and nutrition in sports, with a particular focus on altitude training.

The researcher meets young athletes who are willing to do everything for their sport and have high ambitions. Many of them are football players, which is one of the sports with a high injury rate.

"Some of them misunderstand what it means to eat correctly and are a little too preoccupied with what is healthy. Some of them actually eat too healthily," she says.

Football is particularly popular

Organised sport is highly popular among Norwegian youth and forms a vital part of most young people's lives.

74 per cent have been members of a sports club since starting lower secondary school. 92 per cent have participated in organised sports since childhood, according to ungdata.no.

Ungdata is a national data collection scheme that provides information about adolescents' health and well-being.

Many train actively in pursuit of ambitious sporting careers, and football is especially popular.

What does it mean to eat 'too healthily'?

According to the nutritionist, it is not uncommon for young athletes to choose foods that contain very little energy relative to their volume.

"Many are focused on ensuring there is minimal sugar, that the food is low-fat, and that it's 'clean food,' meaning as little ultra-processed food as possible," Koivisto-Mør summarises.

As a result, young people risk eating food that makes them feel very full while their bodies still receive too little energy during a vulnerable stage of development.

Ambitious young athletes who train heavily and are still growing require a significant amount of extra energy, the researcher points out.

Koivisto-Mørk believes that the extra energy found in things like desserts, sweets, and baked goods can be beneficial when you train a lot.

She is supported by Håvard Moksnes, a sports physiotherapist at the Sports Health Centre, who is affiliated with the medical support team for Norway's women’s national football team. He also has a PhD in knee injuries in children.

Intense training can make you less hungry

You might think that young people who train and become very hungry would devour large amounts of food to make up for the energy they use in their sport. And indeed, many do.

Former football player and current sports commentator Andrine Hegerberg has talked about how she and her sister ate everything they could get their hands on when they were young football players.

They would often eat cinnamon buns to ensure they met their energy needs.

"However, the vast majority of athletes who struggle with energy deficiency do not deliberately restrict their food intake. They simply don't know how much they need in relation to how much they train," Moksnes explains.

We also know that very intense and hard training can negatively affect appetite, Koivisto-Mørk says. According to the Norwegian Health Informatics website, intense training sessions can suppress levels of the hunger hormone ghrelin.

"We often have to tell athletes that they must remember to eat even if they do not feel hungry. It is essential to establish good routines for regular food intake," the researcher says.

Ask what they are eating!

A good place for parents and coaches who are concerned about an athlete is to ask: 'What did you have for breakfast today?'

"Because the answer is often 'I don't eat breakfast'," Moksnes says.

If the athlete replies, 'I had oatmeal with lots of toppings,' that is excellent. That kind of oatmeal is something that many young athletes eat nowadays, he explains.

Follow up by asking what the athlete ate for their evening meal, and the conversation is underway. Moksnes says that he asks his own patients these questions. If the answers give him cause for concern, he refers them to a clinical nutritionist.

A good diet prevents injuries

According to Skadefri.no, food intake should cover the energy required for all the processes occurring in the body, independent of training and activity.

This is known as the resting metabolic rate. In addition, food needs to provide enough energy for all everyday activities, as well as training and competitions.

Several thousand children and young people in Norway suffer from sports injuries every year. The most common injuries are bone fractures, injuries to growth zones, and overuse injuries.

Stress fractures affect an estimated eight per cent of young female football players. Football tops the statistics due to the high number of active participants, followed by basketball, handball, and sports that require a lot of jumping and physical contact.

As competition in sports becomes more important, both training intensity and training volume increase for many young athletes. According to Olympiatoppen.no, approximately 3 to 11 per cent of school children are injured every year in sports.

Sports injuries can be prevented with simple measures

Research from the Oslo Sports Trauma Research Centre shows that half of all sports injuries can be prevented with simple measures such as strength, balance, and joint-control training.

Proper recovery is also absolutely essential for getting the full benefit from training and is crucial for preventing overuse and injury. A good and varied diet is a vital part of this.

This also applies when you are injured and sitting on 'the bench.' It is during the recovery phase that the body rebuilds itself after training. Good recovery means eating enough, drinking enough, and getting enough rest and sleep, according to Moksnes.

When the body is injured, it needs nutrients and energy ‒ often more than most people think ‒ to heal and avoid unnecessary loss of muscle mass, Koivisto-Mørk adds.

If you do not eat enough, healing will be delayed, and the rehabilitation period will last longer.

Are you worried about RED-S?

RED-S is an abbreviation for Relative Energy Deficiency in Sport.

It's a syndrome that occurs when the body, over time, receives too little energy relative to its needs. This is caused by an imbalance between training, daily activities, and food intake.

Training can steal so much of the total daily energy intake that too little is left for the body's normal functions, as well as growth and development.

RED-S can affect both boys and girls who participate in sports ‒ especially those who train a lot.

Adolescents undergoing rapid growth can also be at risk.

Symptoms can include fatigue, decreased performance, repeated injuries and stress fractures, menstrual disturbances in girls, lack of morning erections in boys, and delayed growth and development in young people.

Poorer benefit from altitude training?

Research suggests that athletes with RED-S may also get less benefit from altitude training. In addition to sufficient energy, the body also needs protection from antioxidant-rich foods, says Koivisto-Mørk.

She has investigated whether an increased intake of antioxidant-rich food, served as snacks between meals, affected physiological adaptations in adult elite endurance athletes training at altitude. She also studied inflammation and oxidative stress.

The results showed that doubling the daily intake of antioxidant-rich foods during a training camp at moderate altitude increased the body's capacity to absorb antioxidants. It also reduced some of the inflammation that the body can develop during altitude training.

A daily intake of smoothies, dried fruit, berries, nuts, and dark chocolate increased antioxidant levels in the blood and contributed to a better composition of nutrients in the diet. But it did not reduce oxidative stress.

Her research highlights that energy- and nutrient-dense snacks are a smart choice during altitude training.

Koivisto-Mørk recommends eating enough and aiming to 'eat a rainbow' every day. Ensure you get plenty of colours throughout your training day, even when training at altitude, and preferably in concentrated form so you do not become full too quickly.

Reference:

Koivisto-Mørk, A.E. Nutrition and altitude training in elite endurance athletes: The impact of antioxidant-rich foods and iron in optimising the outcome of training at moderate altitude, Doctoral thesis at the University of Oslo, 2026.

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Read the Norwegian version of this article on forskning.no

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