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Table 3.8 summarises the recommendations on carbohydrate intake covered in this chapter. The simplest way to plan your daily food intake is to divide the day into four ‘windows’: before, during, and after exercise, and between training sessions. You can then work out how much and what type of carbohydrate to consume during each ‘window’ to optimise your performance and recovery.

THE COMPLETE GUIDE TO SPORTS NUTRITION

Summary – what, when, and how much carbohydrate?

Before exercise During exercise After exercise Between workouts

lasting > 60 min

How 2.5 g/kg of body 30–60 g/hour 1 g/kg body 5–10 g/kg body

much weight weight weight, or 60% of

energy

Time 2–4 hours before Begin after 30 Up to 2 hours; 4–6 meals/snacks

period exercise min; regular then every 2 hours

intervals

GI Low High High or low Low

Examples • Jacket potato • 500–1000 ml • Meal replacement • Pasta or rice with

with beans, isotonic drink or shake beans/chicken/

chicken or diluted fruit juice • Fresh fruit with fish

cheese (6 g/100 ml) milk or yoghurt • Noodles with

• Pasta with • Energy bar with • Sports bar tofu/poultry/

tomato based water • Tuna or cottage seafood

sauce and salad • 1–2 handfuls of cheese sandwich • Beans on toast

• Porridge raisins (40–80 g) • Jacket potato

• Rice with chicken • 1–2 bananas with cottage

and vegetables cheese/tuna

SUMMARY OF KEY POINTS

weight/ day is recommended for most regular exercisers, and 7–10 g/ kg body weight/ day is recommended during periods of intense training.

• The glycaemic index (GI) is a more useful way of categorising carbohydrates for athletes than the traditional ‘complex’ versus ‘simple’ classification.

• The GI is a ranking of carbohydrates based on their immediate effect on blood glucose (blood sugar) levels. Carbohydrates with a high GI produce a rapid rise in blood sugar; those with a low GI produce a slow rise in blood sugar.

• The glycaemic load (GL) takes into account the GI as well as the amount of carbohydrate (serving size) consumed and thus provides a measure of the total glycaemic response to a food or meal. GL = GI (%) × grams of carbohydrate per serving.

• Low GI foods consumed 2–4 hours before exercise may help improve endurance and delay fatigue. High GI foods consumed pre- exercise benefit some athletes but may produce temporary hypo glycaemia at the start of exercise in those athletes sensitive to blood sugar fluc tuations.

• The pre-exercise meal should contain approx. 2.5 g carbohydrate/kg body weight. • For moderate–high intensity exercise lasting

more than 60 minutes, consuming 30–60 g moderate or high GI carbohydrate (in solid or liquid form) during exercise can help maintain exercise intensity for longer and delay fatigue.

• Glycogen recovery takes, on average, 20 hours but depends on the severity of glycogen depletion, extent of muscle damage and the amount, type and timing of carbohydrate intake.

• Glycogen replenishment is faster than normal during the 2-hour post-exercise period. To kick-start recovery, it is recom - mended to consume 1 g moderate–high GI carbohydrate/kg body weight during this period.

• High or moderate GI carbohydrates produce faster glycogen replenishment for the first 6 hours post-exercise which is most important for athletes who train twice a day.

• A low GI recovery diet may improve endurance the next day, and increase fat utilisation during subsequent exercise. • Combining carbohydrate with protein has

been shown to be more effective in promoting muscle glycogen recovery and muscle tissue growth compared with carbohydrate alone.

• A low GI daily diet comprising 4–6 small meals and supplying 5–10 g/kg body weight (depending on training hours and intensity) will promote efficient muscle glycogen recovery as well as improve satiety and appetite control, reduce cardiovascular risk factors and improve the management of type 2 diabetes.

• A modified form of carbohydrate loading may improve endurance capacity by 20% and performance by 2–3%.

The importance of protein – and the question of whether extra protein is necessary – for sports performance is one of the most hotly debated topics among sports scientists, coaches and athletes and has been contended ever since the time of the Ancient Greeks. Protein has long been associated with power and strength, and as the major constituent of muscle, it would seem logical that an increased protein intake would increase muscle size and strength.

Traditionally, scientists have held the view that athletes do not need to consume more than the RDA for protein and that consuming anything greater than this amount would produce no further benefit. However, research since the 1980s has cast doubt on this view. There is considerable evidence that the protein needs of active individuals are consistently higher than those of the general population.

This chapter will help to give you a fuller understanding of the role of protein during exercise, and enable you to work out how much you need. It will show how individual requirements depend on the sport concerned and the training programme, and also how they are related to carbohydrate intake. An example of a daily menu is given to show how to meet your own protein requirements, and to provide a basis for developing your own menu. As more athletes are giving up meat and choosing a vegetarian diet, this chapter explains how you can obtain sufficient protein and other nutrients for peak performance on a meat-free diet.

Protein supplementation is discussed in detail in Chapter 6.

WHY DO I NEED PROTEIN?