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Nutrition and Performance in Sport

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Christophe Hausswirth

Chapter 4. Nutrition and specific sport populations

Topic 16. The young athlete

Christophe Hausswirth, Véronique Rousseau, Amélie Fosse, Axel Heulin, Yann Le Meur, Eve Tiollier et École Lenôtre

Texte intégral

Questions and answers

Key points
The younger the athlete, the more important it is to keep nutritional information non-technical and simple.
Young athletes should be encouraged to get involved in selecting their diet, whether for meals or for their specific needs during training sessions and competitions.
The message delivered to the young athlete regarding what is “good” or “bad” must be reflected as far as possible in their coach’s plate.
Even though fluid intake is not restricted, young athletes often do not drink enough during training. Adults voluntarily rehydrate (with water) to about 80% of their water loss, whereas young athletes only achieve around 45% compensation.

Is there any difference between young and adult athletes in terms of nutritional approach?

1When young athletes are taught the importance of nutrition in their sporting activity, coaches should take into account the changes that can occur due to development, maturation and personality. Athletes should be encouraged to develop good eating habits from an early age. Coaches should also remember that during adolescence, young athletes have a desire for increasing independence when choosing and preparing their food.

2Physiological changes occur with age for several parameters. For instance, in young people, thermoregulation mechanisms are less efficient than in adults, and they must therefore pay particular attention to their environment, types of activity, clothing and hydration to avoid hyperthermia or hypothermia.

What strategies can be used to educate young athletes on nutrition?

3 Keep it simple: the younger the athletes, the more important it is to keep nutritional information non-technical and straightforward. It is also important to refrain from terms indicating obligations. In addition, information about antioxidants should be provided, explaining why these elements are important for their training and indicating which foods are good sources. Finally, it is important to convey messages relating nutrition to sporting performance: a promise of sporting success can be a strong motivational factor in developing healthy eating habits.

4 Create a solid base: young athletes should be encouraged to get involved in elaborating their diet, whether by preparing meals or determining the specific needs related to their training sessions and competitions. It is important to convey positive messages about good food practices and to insist on the right choices in terms of food and drinks, as these choices contribute to sporting success and constitute the basis of a healthy lifestyle. Thus, young people must familiarize themselves with the food pyramid, as presented oppsoite, be aware of its importance, and understand how foods are classified.

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Photo credit: Fotolia

5 Repeat messages: before and after each training session, basic nutritional principles should be repeated so that young athletes integrate them as quickly as possible. In parallel, breaks during training sessions and/or post-exercise snacks should be used to reinforce food recommendations more specifically linked to the sport practised.

6 Teach by example: in general, younger athletes tend to imitate their coaches when composing meal trays. Therefore, it is essential that the coach set a good example, that the message delivered be practised, at least when eating together. Thus, any advice given to young athletes relating to what is “good” or “bad” must be “visible” as far as possible in the coach’s plate.

How important is nutrition for growth?

7During adolescence, growth requires a balanced diet combining appropriate energy, protein and mineral intake. Young athletes may have difficulties satisfying their energy and nutrient requirements because the energy expended during training must be added to that used for growth. A persistently inappropriate energy intake can lead to reduced stature, irregular menstrual cycles or risks of injury.

8 Carbohydrate requirements: glycogen stores are lower in younger people than in adults, as are the enzymes associated with glycogen storage. In general, young athletes should have a higher carbohydrate intake, including during recovery. Thus, a daily intake of 4.8 g.kg−1 appears to be sufficient to fully replenish glycogen stores. It is also recommended that unrefined cereals, fruit, vegetables, milk and other sources of carbohydrates also containing vitamins, minerals and fibres be included in the diet. In younger athletes, refined carbohydrates (energy gels, bars, drinks, etc.) are recommended during training sessions and competitions, but it is important that they rinse their mouths to maintain good oral hygiene.

9Carbohydrate recommendations based on exercise intensity:

  • to 5 g. kg−1 carbohydrates for light training;

  • to 8 g. kg−1 during moderate to intense training;

  • to 9 g. kg−1 before intense training sessions or competitions;

  • 1.7 g. kg−1 during recovery (in the two hours following exercise).

10 Lipid requirements: in contrast with adults, young people oxidize more lipids than carbohydrates during exercise. Even though lipids are, for them, an essential energy source during exercise, there is no evidence that a fat-rich diet improves performance. Indeed, a fat-rich meal can trigger a 40% decrease in the secretion of growth hormone during exercise. However, young people who avoid eating fats must be carefully monitored, as this can lead to reduced intake of essential fatty acids and fat-soluble vitamins.

11Recommendations for lipids:

  • in young athletes, about 20 to 30% of the total energy intake should be provided by fats;

  • make sure you limit saturated fatty acids and favour unsaturated fats;

  • fat intake should be based on oils rather than cakes and pastries;

  • if fats are completely omitted this can lead to a decrease in meat consumption which will limit intake of minerals like iron, zinc and selenium.

12 Protein requirements: in young athletes, proteins are used for construction, maintenance and repair of the muscles and other tissues. In general, an inadequate calorie intake affects the protein balance. Therefore, athletes should make sure to eat enough calories every day to maintain their body weight and protein structures. There is no scientific evidence that adding non-food proteins to an adolescent’s diet has any beneficial effects.

13Recommendations for proteins:

  • young people who have just increased their training load need 1 to 1.5 g. kg−1 of proteins per day;

  • adolescents who do endurance training need 1.2 to 1.4 g. kg−1 of proteins per day;

  • young athletes adhering to a vegetarian or vegan diet must be monitored to make sure that they consume enough food rich in proteins of vegetable origin, and in appropriate amounts.

Are iron and calcium important for growth in young athletes?

14Young female athletes are particularly subject to iron deficiencies during menstruation. According to some studies, during their period their iron reserves could be decreased by up to 40 to 50%. These low iron values necessarily lead to anaemia, which impairs muscle metabolism. Iron deficiency in young athletes can be avoided by an appropriate diet, and it is important to inform them of this. Iron supplementation may be recommended in some cases, but should only be applied under medical supervision.

15The recommended daily intake of calcium in young athletes corresponds to the amounts necessary to maintain a positive calcium balance, which is essential to promoting bone growth. Many studies indicate that there are no benefits to absorbing too much calcium or too many calcium-rich foods to promote retention. On the contrary, daily intakes below 400 mg are deleterious in growing adolescents and must be readjusted as quickly as possible, since about 26% of bones develop during puberty. All exercises associated with weight bearing (jumps, volleyball, basketball, gymnastics, etc.) stimulate bone mineralization. Other data indicate that these benefits are even greater when these sports are practised before puberty. It is also important to note that poor mineral quality can lead to bone weakening and the appearance of stress fractures: in young athletes about 21% of this type of fracture are due to low calcium levels.

With regard to hydration, is there any difference between young and adult athletes?

16Even though young athletes may sweat less than adults, it has been shown that they can dehydrate just as rapidly if they do not drink enough during exercise. At equivalent hydration levels, a greater increase in body temperature is noted in young athletes. In addition, low sweating levels associated with a greater energy cost of locomotion makes thermoregulation even more difficult for young athletes. It should also be noted that as young people adapt to heat with more difficulty, particular attention must be paid to those who have to train in a hot atmosphere, or even a hot and humid atmosphere, as they will be more vulnerable than older athletes.

17It is well known that even when drinks are unlimited, young athletes in training do not drink enough. Voluntary rehydration (with water) in adults compensates for about 80% of water lost, whereas in young athletes it only compensates for around 45% of the water lost due to activity, i.e. barely half their requirements during exercise. However, it was recently shown that voluntary rehydration could be increased by almost 50% in young athletes by adding 6% sugar and a pinch of salt to each litre of water. Sports drinks are recommended when exercise lasts longer than one hour; young people are encouraged to drink them regularly during training. After exercise, drinking water containing some sodium (salt) is highly recommended. This applies to both adolescents and adults, as it allows better replenishment of the fluids lost during exercise.

18It is essential to teach young athletes to identify the first signs of dehydration (thirst, irritability, headaches, weakness, cramps, nausea, dark urine, drop in performance level, etc.).

19Hydration recommendations for young athletes:

  • before exercise: 750 ml in the two hours preceding the effort;

  • during exercise: favour rehydration every 15 to 20 minutes even if you do not feel thirsty (drink at least 250 ml every 15 minutes);

  • after exercise: compensate for water losses caused by exercise, in a proportion of 1.5. Each kilogram lost must be replaced by drinking 1.5 l of water.

Practical applications

1. Hydration advice

Image 10000000000000230000001F5B2871AD.jpgRemember: drink a lot of water throughout the day and before you feel thirsty (See Fact sheet No. 10 Hydration, p. 342)

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2. Reference daily intake

20 Fruit and vegetables to get plenty of fibre, vitamins, minerals and trace elements

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21Eat 3 pieces of fruit every day, fresh, if possible, and vary the type of fruit

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22Eat at least 2 portions of vegetables every day (cooked and/or raw)

23 Starchy foods to get plenty of energy

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24Have one portion of starchy food at each of the 3 main meals, and adapt the quantity depending on energy expenditure

25 Dairy products for strong bones

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26Eat 3 to 4 dairy products every day, favouring yoghurt, fromage blanc, soft cheese with 20% fat content and semi-skimmed milk

27 Proteins for muscle maintenance and development

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28Eat 2 portions of meat, fish or eggs per day, preferably adapting the portion in line with your body weight

29 Quality oils

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30Fats Have at least 2 tablespoons of high-quality oil (rapeseed oil, walnut oil, olive oil) every day

31 Sweet product, occasionally, for the feel-good factor

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32Preferably during recovery periods

33 Hydration

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34Drink water

3. Dealing with fatty, salty, sweet foods and alcoholic drinks

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4. Meal composition

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5. Calcium and vitamin D

Meeting your calcium needs

35 For young athletes, the Dietary Reference Intake for calcium is about 1200 mg per day

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Vitamin D: a few markers to cover your requirements

Image 10000000000000230000001F5B2871AD.jpgYoung athletes often suffer from vitamin D deficiency

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6. Iron

Meeting your needs

36 The DRI for young athlets can vary based on gender and is estimated at:

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37 A few indications

38(The number of + indicates a higher or lower amount of iron)

39The best iron sources are giblets, shellfish and meat (vary the sources)

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7. Further advice

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Recipe

Free-range chicken burger with Mediterranean vegetables

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Photo credit: Thibaut Ruggeri.

40Serves 2

41Preparation time: 20minutes

42Cooking time: 20minutes

Difficulty: Image 10000000000000290000001D1B459C4A.jpg

43Ingredients

44 250 g free-range chicken breast

45 2 burger buns

46 1 eff yolk

47 Salt, pepper

48 1 g curry powder

49 5 g tarragon

50 2 slices of buffalo mozzarella

51 50 g rocket

52 5 g balsamic vinegar

53 5 g olive oil

54Wash the vegetables and dice them finely. Sweat the onions and garlic in olive oil. Add the pepper and tomato purée, followed by the courgette and aubergine. Season to taste.

55Once the vegetables are fully cooked, add the chopped basil and olives.

56Mince the chicken breasts.

57Add the egg yolk, the chopped tarragon, the curry powder, salt and pepper.

58DIvide the mixture in two and form into 1.5-cm-thick round patties. Grill them.

59Cut the burger buns in two and heat them up. Dress the rocket with vinegar and olive oil.

60Southern-style Vegetables

61 50 g oinions

62 60 g red bell peppers

63 60 g courgettes

64 60 g aubergines

65 10 g Taggiasca black olives

66 5 g olive oil

67 1 crushed garlic clove

68 10 g tomato purée

69 5 g fresh basil

70Compose the burger starting with half the rocket, followed by the Mediterranean vegetables, the chicken patties and finally the mozzarella. Put it in the oven for a few minutes to melt the cheese. Finish with the rest of the rocket and the other half of the burger bun.

71Chef’ snote

72This burger is ideally suited to young athletes. It provides a quarter of the DRI for calcium, a third for iron and half for vitamin C. This dish is rich in protein and lipid. It should thus be combined with a carbohydrate-based starter or dessert. It is also advisable to have a dairy product as an additional source of calcium (for instance, rice pudding, a yoghurt drink or a "Banana-raspberry smoothie" see p. 240)

73Nutritional analysis per person

Energy (Cal)

Carbs (g)

553

32

Lipids (g)

Protein (g)

25

50

Iced berry soufflé, raspberry coulis

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Photo credit: Thibaut Ruggeri.

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74For 8 soufflés

75Preparation time: 30 minutes

76Freezing: 1 hour

Difficulty: Image 100000000000002D0000001F32CD82F2.jpg

77Ingredients

78 145 g granulated sugar

79 35 g water

80 105 g egg yolks

81 75 g raspberry pulp

82 75 g strawberry pulp

83 350 g fromage blanc with 20% fat content

84 Fresh raspberries for decoration

85Dissolve the sugar in the water, boil until the temperature reaches 120 °C. Pour the hot sugar onto the egg yolks and whip the mixture until it cools (about 30 °C).

86Beat the fromage blanc.

87Add the raspberry and strawberry pulp to the egg yolk and sugar mixture.

88Fold in the fromage blanc.

89Pour into verrines or individual moulds.

90Leave in the freezer for 1 hour.

91Serve on plates or in verrines, with the fresh raspberries and raspberry coulis.

92Raspberry coulis

93 200 g raspberries

94 40 g granulated sugar

95 Juice of 1 lemon

96To make the coulis, blend the raspberries with the sugar and lemon juice. Strain to remove the seeds and store in the fridge.

97Chef’s note

98This dessert is rich in calories and carbohydrates. It is a good alternative to ice cream.

99Nutritional analysis per person

Energy (Cal)

Carbs (g)

189

30

Lipids (g)

Protein (g)

5

6

Auteurs

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