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Nutrition and Performance in Sport

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Christophe Hausswirth

Chapter 1. Nutrition: from training to competition

Topic 1. Energy recovery

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

Texte intégral

Questions and answers

Key points
During the recovery phase after exercise (0 to 4 hours), it is recommended that 1 to 1.2 g.kg−1.h−1 of carbohydrates be provided at short intervals. It is particularly important to consume carbohydrates in the 30 minutes following exercise.
To accelerate glycogen resynthesis, protein (0.2 to 0.5 g per day and per kilo) must be added to these carbohydrates, at a 3 to 1 ratio (carbohydrates to proteins).
It is useful to divide the carbohydrate intake over the early stages of recovery, especially when a meal is not scheduled soon after exercise.
In terms of restoring glycogen, carbohydrates in liquid form are as effective as carbohydrates in solid form.
Carbohydrates with a moderate or high glycaemic index supply energy rapidly for glycogen resynthesis during recovery. They should therefore be a priority choice in post-exercise energy-restoring menus.

Why is energy replenishment so important for high-level athletes?

1The majority of energy needs are supplied by carbohydrates (CHO) and lipids. Although the body’s lipid stores are not used during exercise, the glucose stored as glycogen in the liver and the muscle can be depleted during repeated training sessions. This is even more likely in disciplines where the athlete trains several times a day. Therefore, post-exercise glycogen replenishment must be a priority for athletes’ diets, especially during intense training periods. Failing that, a state of chronic fatigue can develop and performance levels decrease.

2The body’s glucose reserves are low (˜25 g); therefore, new glucose must be permanently supplied by food sources. When this dietary glucose is in excess of what is needed to replenish the glycogen stores of various tissues, it will be converted into lipids in the liver and stored in adipocytes. Glucose alone represents 80 to 90% of the energy supplied by carbohydrates.

Does the timing of carbohydrate ingestion influence the efficiency of energy storage after training?

3The carbohydrate intake and its precise “timing” during the recovery phase affect the quality of glycogen resynthesis. It is therefore very important to adopt an appropriate strategy during demanding one-off events (such as triathlon or marathon), and during events where competitive legs are repeated throughout the day (such as swimming, middle-distance races or repeated judo combats). The sooner carbohydrates are consumed after completing exercise, the greater the amount of muscle glycogen resynthesized. Thus, when carbohydrates are ingested immediately after exercise, the muscle glycogen levels measured six hours later is higher than when the intake of carbohydrates is delayed for two hours after completing exercise. These results are particularly relevant for relatively short recovery periods (between 6 and 8 hours). When recovery is longer (between 8 and 24 hours), glycogen resynthesis is not improved by consuming carbohydrates immediately after exercise. For high-performance athletes who train twice-daily, it is recommended that food be consumed rapidly after exercise to promote replenishment of glycogen stores and thus avoid penalizing the second training session. This strategy is mainly recommended for high-level athletes, athletes who do not train more than once a day do not need to rush to consume carbohydrates just after exercise, but should plan to consume a meal or snack containing an adequate supply of carbohydrates before the next training session.

4Several carbohydrate strategies can be used, according to preference. Some athletes prefer to eat solid, sugar-rich foods as part of their main meal, while others favour several snacks, depending on the day’s training. Studies investigating 24-hour recovery periods have shown that large carbohydrate-rich meals taken twice a day or carbohydrate-based snacks repeated several times a day have an equivalent capacity to reconstitute muscle glycogen stores. Similar results were found for high-performance athletes consuming four complex carbohydrate-based meals per day, or 16 snacks (one per hour). However, in this study, while glycogen resynthesis rates were similar in both conditions, the blood glucose and insulin concentrations differed over the course of the 24 hours. Elsewhere, very high rates of glycogen synthesis were reported over the first 4 to 6 hours of recovery when large amounts of CHO were ingested at 15 to 30-minute intervals. The high rates observed with this dietary protocol were attributed to the maintenance of elevated insulin and blood glucose levels. The apparent discrepancy between these results and the previous ones may reside in the fact that concentrations were not compared to those measured in protocols where several CHO-based snacks were offered to athletes. It appears, however, that the maximal rate of glycogen resynthesis measured during recovery is obtained when athletes consume 0.4 g.kg−1 body weight every 15 minutes (i.e. 120 g CHO per hour for a 75-kg subject) over the 4 hours immediately following completion of exercise.

Does sugar type influence recovery?

5Ingesting sugar-containing food during the recovery phase leads to two phenomena: an increased rate of glycogen resynthesis, and levels of glycogen exceeding those available prior to exercise. The glycogen resynthesis capacity is also affected by the type of sugars available. The speed of muscle glycogen resynthesis is identical during recovery whether glucose or glucose polymers are ingested, but it is slower when fructose is consumed. In contrast, fructose increases the rate of hepatic glycogen resynthesis, as long as glycogen synthesis is promoted by insulin activity. Because of this, during recovery, it is more effective to consume carbohydrates with a high glycaemic index. (The glycaemic index is an indicator of the physiological reaction to an oral carbohydrate intake).

6Some recent data show that for some carbohydrates with a low glycaemic index, their availability in the intestine is over estimated due to poor digestibility. Indeed, a longitudinal study (carried out over 30 days) showed that, in an active population exposed to a daily diet containing only low glycaemic index foods, glycogen synthesis was reduced compared to initial values and values for a similar population consuming a high glycaemic index diet. These data should be kept in mind by athletes who must take part in daily training sessions and/or repeated events. From this observation, we must therefore be careful when recommending diets with a low glycaemic index, as these do not always promote optimal glycogen resynthesis.

How does the amount of carbohydrates consumed during the recovery phase affect glycogen resynthesis?

7The first studies investigating the amounts of carbohydrate consumed during post-exercise recovery showed that an intake of 150 to 600 g of carbohydrates per day was optimal for replenishing glycogen stores over a 24-hour period. A few years later, it was shown that consuming 1.5 g carbohydrates per kilogram of body weight over the 2 hours following an exhausting exercise induced an appropriate rate of glycogen resynthesis. This rate was not improved by doubling the amount of carbohydrate (i.e 110 g carbohydrates per hour for a 75-kg subject). Similarly, no difference was recorded with 460 or 620 g of post-exercise carbohydrate per day. In contrast, doses of only 160 or 360 g carbohydrate per day significantly diminished the levels of muscle glycogen resynthesized when comparing levels before and after exercise.

8The amount of carbohydrate that should be consumed during recovery after exercise has been the subject of many studies. Thus, various energy drinks have been marketed to maintain athletes’ plasma and blood volumes. As part of this, some authors have tested the influence of a drink containing 7% glucose (and electrolytes) on haematocrit and haemoglobin levels measured after a football match, comparing it to the effects observed with a drink containing no glucose. The data for 44 football players showed that the energy drink stabilized plasma volumes during recovery, while the electrolyte-only drink did not maintain the blood volume (resulting in a 5% reduction in plasma volume).

Is co-ingestion of carbohydrates and proteins advantageous for recovery?

9The combination of carbohydrates (CHO) and proteins (PRO) has recently been suggested to improve the speed of glycogen resynthesis. This appears to be linked to higher insulin secretion levels induced by the combination than those triggered by CHO alone. Somewhat contradictory results have been obtained regarding the potential benefits of combining CHO and PRO. The differences noted could be due to the experimental protocol applied, to the frequency of supplementation, or to the amounts of CHO and PRO consumed by athletes.

10Combining intake of proteins and carbohydrates during recovery aims primarily to increase insulin production. This hormone is essential for glycogen synthesis, as it affect both glucose penetration into muscle fibres and the activity of glycogen synthase, which is the limiting enzyme in glycogen synthesis. In most cases, consuming a mixture of CHO and PRO should promote a stronger insulin response. The first study showing the efficacy of combining CHO and PRO was carried out in athletes after 2 hours’ ergocycle training performed after a 12-hour fast. Glycogen resynthesis was assessed four hours after consuming solutions containing a mixture of CHO and PRO, or 112 g CHO or 40.7 g PRO alone. The results of this study showed that the amount of glycogen generated per hour is significantly greater in athletes consuming the mixture of CHO and PRO. In the same context, Williams et al. (2003) asked eight endurance-trained cyclists to perform 2 hours’ cycling on an ergocycle at 65 to 75% VO 2 max, and then, after 2 hours’ recovery, to complete a time to exhaustion at an intensity of 85% of VO2 max. CHO alone or a mixture of CHO and PRO was consumed immediately after exercise and two hours later. The results show a significant increase (128%) in muscle glycogen resynthesis for the “CHO–PRO” condition. Consumption of the solution containing CHO and PRO also improved the time to exhaustion, with a single cyclist performing less well in the “CHO–PRO” condition, while all the others significantly improved their performances. The times to exhaustion measured were, 31 minutes in the “CHO–PRO” condition, compared to only 20 minutes with “CHO alone”.

11A final recent study examined the effect of one hour of time-trial cycling in six experienced cyclists. Study subjects then consumed defined meals and solutions, immediately, and then 1 or 2 hours after exercise. The nutritional composition was as follows: (C + P: carbohydrate + proteins; CHO: carbohydrate; placebo: solid food placebo). After 6 hours’ recovery, a second 1 hour time-trial was performed. Although cycling performances were similar during the two trials, the rate of muscle glycogen resynthesis was greater (+ 23%) in the “C + P” condition than in the “CHO alone” condition. This final result has an undeniable impact: when post-exercise nutrition must be spaced out and when a second exercise period is to be performed after only a short recovery period, the combination of carbohydrates and proteins presents great advantages in terms of increasing the speed of glycogen resynthesis.

Practical applications

1. Composition of post-exercise snack

12Immediately after exercise, the athlete especially needs carbohydrates and a small amount of protein.

13As little fat as possible should be eaten (chocolate, fried foods and other fatty foods).

A snack should be eaten immediately after exercise – if no meal is scheduled within 30 minutes

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2. Composition of post-exercise meal

When the meal is eaten immediately after a long, intense training session

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3. Selecting the snack to be eaten during training

14After exercise, the athlete needs carbohydrates combined with protein and water.

Choose at least

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4. Selecting the post-competition snack

15After exercise, the athlete needs carbohydrates (around 50 to 100 g, depending on body weight), combined with proteins (around 5 to 15 g, depending on body weight).

Choose at least

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Recipe

Chicken curry ciabatta sandwich, vegetable chop suey

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Photo credit: Thibaut Ruggeri.

16Serves 2

17Preparation time: 30 minutes

18Cooking time: 20 minutes

Difficulty: Image 10000000000000290000001EC3F9334F.jpg

19Chicken curry

20 2 skinless chicken breasts

21 10 g curry paste

22 120 g coconut milk

23 Salt, pepper

24 10 g olive oil

25Mix the curry paste with the coconut milk.

26Place the chicken breasts in the mixture and leave to marinate for 30 minutes (this can be done the day before).

27Season the chicken and fry gently.

28Finish off cooking in the oven (140 °C for 10 minutes). Allow to cool.

29Vegetable chop suey

30 100 g peeled carrots

31 50 g green bell peppers

32 50 g red bell peppers

33 50 g beansprouts

34 1 tablespoon olive oil

35 20 g soy sauce

36Cut the vegetables into Julienne * strips and fry in olive oil.

37Add the beansprouts and deglaze the frying pan with soy sauce. Season to taste.

38Allow to cool.

39* Julienne strips: long, thin strips, 2 to 3 mm wide

40Presentation

41 2 round ciabatta rolls

42 1/4 chopped iceberg lettuce

43 20 g "Savora" mustard

44 10 g fresh coriander

45Cut the bread rolls in two and brush with half the mustard.

46Add the chopped lettuce.

47Mix the rest of the mustard with the vegetable chop suey and use it to stuff the rolls.

48Add the chicken curry cut into strips and the fresh coriander leaves. Couper les pains en deux puis les badigeonner avec la moitié de la moutarde.

49Chef’s note

50Ce sandwich peut être consommé après l’exercice. Il contient majoritairement des glucides et des protéines et relativement peu de lipides.

51Riche en vitamines A et C (vitamines antioxydantes), il représente également une source intéressante de vitamines du groupe B.

52Si l’exercice est intense, ce plat peut être complété par une boisson ou un dessert sucré (Seeci-contre: Smoothie banane et framboise).

53Nutritional analysis per person

Energy (Cal)

Carbs (g)

377

51

Lipids (g)

Protein (g)

9

23

Banana and raspberry smoothie, Sponge cake

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Photo credit: Thibaut Ruggeri.

54Serves 4 to 6

55Preparation time: 30 minutes

56Cooking time: 50 minutes

Difficulty: Image 10000000000000290000001E6DBDFF89.jpg

57Smoothie: serves 4

58 800 g bananas

59 250 g raspberries

60 150 g plain yoghurt

61 20 g icing sugar

62 100 g semi-skimmed milk

63 1 lemon

64 A few blueberries for decoration

65Wash or peel the fruit.

66Set aside 4 slices of banana and 4 raspberries. Chop the remaining fruit.

67Squeeze the lemon.

68Put all the ingredients in a blender, blend for 1 minute until smooth.

69Pour the smoothie into glasses.

70Decorate with a slice of banana and a raspberry, add the blueberries.

71Sponge cake: serves 6

72 6 egg yolks

73 130 g caster sugar

74 90 g flour

75 70 g potato starch

76 1 lemon zest

77 7 egg whites

78 50 g granulated sugar

79 Butter for greasing the tin

80Preheat oven to 200 °C.

81Beat the egg yolks and the caster sugar until smooth.

82Add the lemon zest.

83Sift the flour and potato starch together.

84Beat the egg whites with 5 g granulated sugar at first, then add the rest of the granulated sugar.

85The whites should be stiff and form smooth, shiny peaks when you raise the whisk.

86Gently mix some of the whites with the sugar and egg yolk mixture, add half the flour.

87Repeat and finish with the remainder of the whites.

88Grease the tin with butter, pour in the mixture and bake in the oven for 5 minutes at 200 °C.

89Reduce the temperature to 150 °C and continue to bake until golden, then turn the oven down to 130 °C for 40 minutes.

90Check that the cake is fully cooked by inserting a skewer into the centre.

91Turn the cake out onto a cooling rack. While it is still warm, wrap it in clingwrap so that it remains moist.

92Chef’s note

93This dish can be eaten as a snack just after exercise or as a dessert.

94It is very rich in carbohydrates and provides a considerable amount of protein.

95It is a good source of vitamin B, vitamin C (a third of the needs) and potassium.

96Nutritional analysis per person

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Auteurs

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