Nutrition - Pre and Post Exercise

Nutrition - Pre & Post Exercise

Eating Before Matches/Training

Many GAA players put a lot of emphasis on the pre-event meal believing it is the key element to performance. It is important to remember that food eaten throughout the training week and food and fluid consumed during the event is just as important. Consuming food and fluid before exercise should be seen as an opportunity to fine-tune carbohydrate and fluid levels and to ensure you feel comfortable and confident.

When should I eat?

Food consumed before exercise is only useful once it has been digested and absorbed. This means you need to time your food intake so that the fuel becomes available during the exercise period. The time required for digestion depends on the type and quantity of food consumed. Generally, foods higher in fat, protein and fibre tend to take longer to digest than other foods, and may increase the risk of stomach discomfort during exercise. Large quantities of foods take longer to digest than smaller quantities. Generally, food is better tolerated during lower intensity activities, or sports where the body is supported (e.g. cycling) than sports such as running where the gut is jostled about during exercise (e.g Gealic Games) A general guide is to have a meal about 3-4 hours before exercise or a lighter snack about 1-2 hours before exercise. You need to experiment to find the timing, amount and make up that best suits your individual needs.

What should I eat?

Food eaten before exercise should provide carbohydrate. It should also be low in fat and moderate in fibre to make digestion easier and reduce the risk of gastrointestinal discomfort. For most exercise sessions, the emphasis on carbohydrate and fluid for the pre-event meal. However, it is also useful to continue to consider other nutritional goals when choosing a pre-exercise meal. This may mean including foods that include protein, vitamins and minerals.

The following foods are suitable to eat 3-4 hours before exercise:

• baked potato + cottage cheese filling + glass of milk
• baked beans on toast
• breakfast cereal with milk
• bread roll with cheese/meat filling + banana
• fruit salad with fruit-flavoured yoghurt
• pasta or rice with a sauce based on low-fat ingredients (e.g. tomato, vegetables, lean meat)

The following snacks are suitable to eat 1-2 hours before exercise:

• liquid meal supplement
• milk shake or fruit smoothie
• sports bars (check labels for carbohydrate and protein content)
• breakfast cereal with milk
• cereal bars
• fruit-flavoured yoghurt
• fruit

The following foods are suitable to eat if there is less than 1 hour before exercise*:

• sports drink
• cordial
• sports bars
• jelly lollies

Are foods with a low glycaemic index better?

Carbohydrate-containing foods have different effects on blood glucose levels. Foods with a low glycaemic index (GI) cause a slower, sustained release of glucose to the blood, whereas foods with a high GI cause a rapid, short-lived rise in blood glucose. It has been suggested that low GI foods could be useful in the pre-event meal as they would result in a slower and more sustained release of glucose during exercise maintaining blood glucose levels for a longer period. However, research has been unable to demonstrate that consuming low GI foods prior to exercise has universal benefits on exercise performance. In addition, consuming carbohydrate (e.g. sports drink) during exercise provides an alternative way to maintain fuel levels throughout the activity and a study has shown that this practice overrides the effects of different types of carbohydrate in the pre-event meal. If you are involved in an endurance event in which it is difficult to take in extra carbohydrate during the session, you may wish to trial low GI foods before exercise. However, keep in mind that many low GI options (lentils, porridge, multigrain bread) may not be suitable as they are more likely to cause stomach discomfort.

What if I play/train early in the morning?

It is not always practical to eat a meal 3-4 hours before exercise. If you train early in the morning you should opt for a light snack about an hour before exercise. For example, some fruit or a cereal bar on the way to training along with some fluid such as a glass of milk or juice. Make up for your smaller carbohydrate intake prior to exercise by consuming carbohydrate during the event or training session.

What if I am too nervous to eat?

You will perform better when you are well-fuelled and well hydrated, and the pre-event meal may play an important role in achieving these goals. Athletes need to experiment to find a routine that works, and foods that are safe and familiar. You may also find that foods such as cereal bars and sports bars can be eaten if you nibble them slowly over the hours leading up to your competition.

Should I avoid carbohydrate 1 hour before playing/training?

Most athletes are able to consume carbohydrate in the hour before exercise without affecting performance, and in some cases it can even improve the outcome of the session. However, a small percentage of athletes experience a drop in blood glucose levels and symptoms such as fatigue, shakiness and dizziness after consuming carbohydrate immediately before exercise. This reaction is a response to the increase in carbohydrate use that occurs after carbohydrate intake, associated with a rise in the levels of the hormone, insulin. When the start of exercise coincides with extra carbohydrate use, it is usual to see a small dip in blood glucose levels. In most people, this is a temporary event which is quickly corrected by the body without any side-effects. However, in a few individuals, the drop in blood glucose is greater, or the individual is sensitive to the change, suffering a pronounced fatigue. If you are affected in this way consider the following advice:

• Experiment to find the best timing for your pre-exercise meal. Try allowing a longer period between eating and exercising.
• If you need to eat close to exercise, opt for a snack that provides at least 70 g of carbohydrate. There is some evidence to suggest that small amounts of carbohydrate (<50>
• Include some low glycaemic index foods (yoghurt, multigrain bread, pasta, oranges) in the pre-exercise meal. These result in a slower release of glucose throughout exercise and a smaller insulin response compared to higher glycaemic index foods.
• Include some high-intensity activity in your warm-up. This helps to stimulate glucose release from the liver and prevents blood glucose levels from dropping too low.
• Consume carbohydrate during the event.

Recovery Nutrition

What are the priorities for recovery nutrition?

Recovery is a challenge for athletes who are undertaking two or more sessions each day, training for prolonged periods, or competing in a program that involves multiple events. Between each work-out, the body needs to adapt to the physiological stress. In the training situation, with correct planning of the workload and the recovery time, adaptation allows the body to become fitter, stronger and faster. In the competition scenario, however, there may be less control over the work-to-recovery ratio. A simpler but more realistic goal may be to start all events in the best shape possible.
Recovery encompasses a complex range of processes that include;
• refueling the muscle and liver glycogen (carbohydrate) stores
• replacing the fluid and electrolytes lost in sweat
• manufacturing new muscle protein, red blood cells and other cellular components as part of the repair and adaptation process
• allowing the immune system to handle the damage and challenges caused by the exercise bout
The emphasis an athlete needs to place on each of these broad goals will vary according to the demands of the exercise session. Key questions that need to be answered include - How much fuel was utilised? What was the extent of muscle damage and sweat losses incurred? Was a stimulus presented to increase muscle protein?
A proactive recovery means providing the body with all the nutrients it needs, in a speedy and practical manner, to optimise the desired processes following each session. State-of-the-art guidelines for each of the following issues are presented below.

Refueling

Muscle glycogen is the main fuel used by the body during moderate and high intensity exercise. Inability to adequately replace glycogen stores used up during a workout will compromise performance in subsequent sessions.
The major dietary factor in post-exercise refueling is the amount of carbohydrate consumed. Depending on the fuel cost of the training schedule or the need to fuel up to race, a serious athlete may need to consume between 7-12 g of carbohydrate per kg body weight each day (350-840 g per day for a 70kg athlete) to ensure adequate glycogen stores. As an overemphasis on other nutrients, such as protein and fat, can easily replace carbohydrate foods within the athlete’s energy requirements, careful planning of meals and snacks throughout the day is needed achieve the required level of intake (for more information on carbohydrate requirements for athletes, refer to the “Carbohydrate” Fact Sheet).
In the immediate post exercise period, athletes are encouraged to consume a carbohydrate rich snack or meal that provides 1-1.2 g of carbohydrate per kg body weight within the first hour of finishing, as this is when rates of glycogen synthesis are greatest. This is especially important if the time between prolonged training sessions is less than 8 hrs. The type and form (meal or snack) of carbohydrate that is suitable will depend on a number of factors, including the athletes overall daily carbohydrate and energy requirements, gastric tolerance, access and availability of suitable food options and the length of time before the next training session. Table 1 gives examples snacks providing at least 50g of carbohydrate.

Rehydration

The majority of athletes will finish training or competition sessions with some level of fluid deficit. Research suggests that many athletes fail to adequately drink sufficient volumes of fluid to restore fluid balance. As a fluid deficit incurred during one session has the potential to negatively impact on performance during subsequent training sessions, athletes need to incorporate strategies to restore fluid balance, especially in situations where there is a limited amount of time before their next training session.
Athletes should aim to consume 125-150% of their estimated fluid losses in the 4-6 hours after exercise (Refer to the “How much do athletes sweat?” Fact Sheet for advice on how to monitor fluid losses during exercise). The recommendation to consume a volume of fluid greater than that lost in sweat takes into account the continued loss of fluid from the body through sweating and obligatory urine losses.
Fluid replacement alone will not guarantee re-hydration after exercise. Unless there is simultaneous replacement of electrolytes lost in sweat, especially sodium, consumption of a large volume of fluid may simply result in large urine losses. The addition of sodium, either in the drink or the food consumed with the fluid, will reduce urine losses and thereby enhance fluid balance in the post exercise period. Further, sodium will also preserve thirst, enhancing voluntary intake. As the amount of sodium considered optimal for re-hydration (50-80 mmol/L) is in excess of that found in most commercially available sports drinks, athletes may be best advised to consume fluids after exercise with everyday foods containing sodium.
In considering the type of fluids needed to achieve their re-hydration goals, athletes should also consider the length of time before their next session, the degree of the fluid deficit incurred, taste preferences, daily energy budget, as well as their other recovery goals. With the latter, athletes can simultaneously meet their refueling, repair and contribute to their re-hydration goals by consuming fluids that also provide a source of carbohydrate and protein e.g. flavoured milk, liquid meal supplement.

Muscle Repair and Building

Prolonged and high-intensity exercise causes a substantial breakdown of muscle protein. During the recovery phase there is a reduction in catabolic (breakdown) processes and a gradual increase in anabolic (building) processes, which continues for at least 24 hours after exercise. Recent research has shown that early intake after exercise (within the first hour) of essential amino acids from good quality protein foods helps to promote the increase in protein rebuilding. Consuming food sources of protein in meals and snacks after this “window of opportunity” will further promote protein synthesis, though rate at which it occurs is less.

Immune System

In general, the immune system is suppressed by intensive training, with many parameters being reduced or disturbed during the hours following a work-out. This may place athletes at risk of succumbing to an infectious illness during this time. Many nutrients or dietary factors have been proposed as an aid to the immune system - for example, vitamins C and E, glutamine, zinc and most recently probiotics - but none of these have proved to provide universal protection. The most recent evidence points to carbohydrate as one of the most promising nutritional immune protectors. Ensuring adequate carbohydrate stores before exercise and consuming carbohydrate during and/or after a prolonged or high-intensity work-out has been shown to reduce the disturbance to immune system markers. The carbohydrate reduces the stress hormone response to exercise, thus minimising its effect on the immune system, as well as also supplying glucose to fuel the activity of many of the immune system white cells.

How does recovery eating fit into the big picture of nutrition goals?

To optimise recovery from a training session, meals (which generally supply all the nutrients needed for recovery) must either be timetabled so that they can be eaten straight after the work-out, or special recovery snacks must be slotted in to cover nutrient needs until the next meal can be eaten.
For athletes who have high-energy needs, these snacks make a useful contribution towards their daily kilojoule requirement. When there is a large energy budget to play with, it may not matter too much if the snacks only look after the key recovery nutrients - for example carbohydrate e.g. sports drink. On the other hand, for those athletes with a low energy budget, recovery snacks will also need to contribute towards meeting daily requirement for vitamins, minerals and other nutrients. Snacks that can supply special needs for calcium, iron or other nutrients may double up as suitable recovery snacks. e.g. yoghurt

What are some other the practical considerations for recovery eating?

Some athletes finish sessions with a good appetite, so most foods are appealing to eat. On the other hand, a fatigued athlete may only feel like eating something that is compact and easy to chew. When snacks need to be kept or eaten at the training venue itself, foods and drinks that require minimal storage and preparation are useful. At other times, valuable features of recovery foods include being portable and able to travel interstate or overseas. Situations and challenges in sport change from day to day, and between athletes - so recovery snacks need to be carefully chosen to meet these needs.

Table 1 - Carbohydrate-rich recovery snacks (50g CHO portions)
• 700-800ml sports drink
• 500ml fruit juice or soft drink
• 300ml carbohydrate loader drink
• 2 slices toast/bread with jam or honey or banana topping
• 2 cereal bars
• 1 cup thick vegetable soup + large bread roll
• 115g (1 large or 2 small) cake style muffins, fruit buns or scones
• 300g (large) baked potato with salsa filling
• 100g pancakes (2 stack) + 30g syrup

Table 2 - Nutritious carbohydrate-protein recovery snacks (contain 50g CHO + valuable source of protein and micronutrients)
• 300g creamed rice
• 250-300ml milk shake or fruit smoothie
• 600ml low fat flavoured milk
• 1-2 sports bars (check labels for carbohydrate and protein content)
• 1 large bowl (2 cups) breakfast cereal with milk
• 1 large or 2 small cereal bars + 200g carton fruit-flavoured yoghurt
• 220g baked beans on 2 slices of toast
• 1 bread roll with cheese/meat filling + large banana
• 300g (bowl) fruit salad with 200g fruit-flavoured yoghurt
• 300g (large) baked potato + cottage cheese filling + glass of milk

Table 3 - Foods providing approximately 10g of protein.

Animal foods
• 40g of cooked lean beef/pork/lamb
• 40g skinless cooked chicken
• 50g of canned tuna/salmon or cooked fish
• 300 ml of milk
• 200g tub of yoghurt
• 300ml flavoured milk
• 1.5 slices (30g) of cheese
• 2 eggs

Plant based foods
• 120g of tofu
• 4 slices of bread
• 200g of baked beans
• 60g of nuts
• 2 cups of pasta/3 cups of rice
• .75 cup cooked lentils/kidney beans