Diet Requirements for Marathon Runners in Training

Why do you need a nutritional plan for marathon training?

You need a nutritional plan for marathon training to ensure you are meeting your body�s increased nutrient requirements. These increased nutrient requirements will depend on your training volumes, frequency and intensity. Your requirements will also vary during the different training phases of the year. The skills you learn when designing your nutritional plane for training can be used to individualize your plan.

Following sound nutrition practices is most important during marathon training. If you think about it, you spend most of your time training and this is largely what determines your performance in competition. Good nutrition will help you maximize your marathon training and your competition performance. Your nutrition on competition day is just fine-tuning of your training nutrition.

Carbohydrate

What is carbohydrate?

 Carbohydrate is broken down by the digestive system and carried around the body as blood glucose.

 The glucose is stored in muscle and the liver as glycogen to be used by the body during activity.

 Glycogen in the liver is released into the blood to maintain normal blood glucose levels.

 Blood glucose is used by muscles and the brain. The brain relies on blood glucose to function properly.

 Muscles use stored glycogen as their primary energy source with blood glucose as an additional source.

 When muscle glycogen becomes low, fatigue occurs in the muscles being used. Muscle glycogen depletion occurs after 2-3 hours of continuous training at low intensity.

 When blood glucose becomes low (hypoglycaemia), marathon runners complain of �bonking� or �hitting the wall�; they no longer have enough glucose in their blood for their brain to function properly.

 Symptoms of hypoglycaemia include poor coordination, light headedness, inability to concentrate and weakness.

Did you know that the term �bonking� comes from the sport of cycling? When blood glucose levels got too low, riders fell off their bikes and �bonked� their heads on the ground!

The Glycaemic Index

 Foods with a glycaemic index ranking of 71-100 are called high GI foods. They increase blood glucose levels quickly, providing a fast source of blood glucose for muscles to take up and use. These foods are good to eat during and after exercise.

 Intermediate glycaemic index foods have a ranking or 55-70 and provide a moderate release of glucose into the blood. These foods are also good during and after exercise.

 Low glycaemic index foods are ranked 0-54 and release glucose into the blood slowly over a longer period of time. These foods should be included in main meals in the marathon training diet and may be useful before exercise.

Examples of foods that have a low, intermediate or high glycaemic index.

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Have you heard about simple and complex carbohydrate?

Examples of simple carbohydrate include fruit juice, dried fruit, sports drinks, milk, sugar, jam, honey, soft drinks and cordials.

Examples of complex carbohydrate include pasta, rice, breads, breakfast cereals, and some fruits and vegetables.

It was thought that due to their chemical structure simple sugars caused a rapid rise in blood glucose while complex carbohydrates caused a more gradual release of glucose into the blood. Recent research has shown that the rise in blood sugar after eating food can also be affected by the type of sugar or starch in the food, the processing or cooking of the food, fat and fibre content and ripeness of the food. It is more useful to rank carbohydrate foods according to the glycaemic index, which takes these factors into account.

Why do you need carbohydrate?

You need carbohydrate to:

Store optimal levels of muscle and liver glycogen before exercise, providing energy and delaying fatigue.

Keep your blood glucose levels topped up during exercise to further delay fatigue.

Replace used up muscle and liver glycogen after exercise so your body can recover faster.

How much carbohydrate do you need?

Timing when you eat

Regular meals

Before marathon training

For example, if you are training at 11am you could have breakfast at 7am and a mid-morning snack at about 9am to provide 200g of carbohydrate.

A 200g breakfast meal and morning snack could consist of 1 cup of cereal with trim milk and a medium banana (50g), 2 slices of toast bread with 2 tablespoons of jam (60g) and 1 glass of fruit juice (20g). For a morning snack you could have a pottle of yoghurt (20g) and a cereal bar (40g).

You need to be practical when planning your pre-training meals. For example if you are planning on a marathon training run at 6am you may not feel like eating much. Have a high carbohydrate meal the night before and aim for a minimum of 50g carbohydrate before early morning training.

For example, you could have a smoothie or a banana and a glass of fruit juice.

How much you eat will also depend upon how long the training session is going to be. If you are planning on a long training run make sure you have at least 200g of carbohydrate in your pre-exercise meal. If you are going for a half hour run you will be fine with a light snack.

For example, a piece of fruit or a slice of toast.

Training is a good chance to experiment with different foods at different times to determine what suits you.

In the past athletes have worried about eating before exercise because it was thought that blood glucose went up and then came down lower than resting levels, reducing performance. Recent research has shown that this does not usually impair performance. In fact, eating before training or competition has a positive effect on performance.

During marathon training

When practicing your during-exercise carbohydrate intake for a competition situation upi should aim to consume 0.5 � 1 gram of carbohydrate per minute, or 30 � 60 grams of carbohydrate each hour to maintain adequate blood glucose.

For example, 500ml of sports drink with 7% carbohydrate will provide 35g of carbohydrate. This is enough to maintain your blood glucose levels.

Sports drinks and foods with a moderate to high glycaemic index will provide glucose quickly to blood for muscles and the brain to use as energy.

After marathon training

Glycogen stores will be replaced most efficiently if you have approximately 1 gram of carbohydrate per kg of bodyweight within the first 30-60 minutes after your marathon training. This should be followed up with a high-carbohydrate meal and regular carbohydrate meals and snacks for the rest of the day.

For example, a 75kg woman needs to eat 75g of carbohydrate in the first 30-60 minutes after her marathon training session. A smoothie made with 400ml of trim milk, a medium banana and 200ml of fruit-flavored yoghurt, as well as a handful of raisins will provide 75g of carbohydrate. She can follow this up with a high carbohydrate meal and snacks.

You need to be able to plan your post marathon training carbohydrate so it is practical and fits in with your main meals and snacks. Although high glycaemic foods will supply glucose to the blood and muscles quickly, it is the total amount of carbohydrate that has the greatest effect on recovery.

Protein

What is protein?

Protein can come from animal and plant sources.

Protein from animal sources contains all essential amino acids.

Protein from plant sources lacks one or more of the essential amino acids. Vegetarians need to plan carefully to ensure all the essential amino acids are provided in their diet.

Why do you need protein?

Some protein in the post-training and post-competition meals can help improve muscle glycogen restoration by increasing the rate glucose is taken into muscles, help in the repair of muscle tissue, and may help optimize gains in lean body mass. The recommended amount of protein post training is 10-20g.

Protein has a small role in providing energy when glycogen stores have been exhausted. When protein is used for energy it cannot be used for the important roles of muscle growth, repair and recovery. By having good glycogen stores you actually spare protein.

How much protein do you need?

It is common for us to eat more protein than needed so it is not usually difficult to meet protein requirements. When marathon runners increase their energy intake they often automatically increase their protein intake.

When you want to gain muscle mass it is important to ensure you consume enough energy, predominantly from carbohydrate. If you do not increase your energy and carbohydrate intake you will actually use some of your body protein to provide energy � you can lose muscle!

Can you have too much protein?

If you eat too much protein you will not be getting enough carbohydrate to meet your energy needs and your body will use the protein as an energy source � this is wasteful!

You will need to urinate more often to get rid of the waste products of protein breakdown. This means many trips to the toilet, an extra strain on your kidneys and the risk of dehydration.

High-protein foods are often high-fat foods.

Protein foods, especially animal protein, tend to be expensive.

A diet high in protein may increase calcium loss.

How can you work out your daily protein needs?

Protein needs per day = body weight x 1.2�1.4g

Marathon runners need an increased protein intake to repair the muscle damage caused by distance running.

Fat

Why do you need fat?

Marathon runners should try and keep fat to a minimum. As a general guideline, the daily intake of fat for a marathon runner should be between 70-100g. Larger, more active men are at the upper end of this range, while women are at the lower.

Fluids

Why do you need fluids?

Fluids are essential to regulate your body�s temperature, transport nutrients and oxygen around your body and act as a medium for reactions to occur.

By drinking adequate volumes of fluids you can meet water needs and: - Reduce the risk of heat illness. - Improve your performance by preventing or reducing dehydration. - Provide a convenient way of consuming carbohydrates.

Dehydration impairs the ability of your heart to work harder and your body to regulate temperature, leading to reduced performance. Dehydration also affects mental function and coordination important for peak performance.

Did you know that sweating is one of the ways your body keeps cool? As a marathon runner your body adapts and sweats more, improving your temperature regulation. It is good to sweat!

Your body is not good at telling you when you need to drink during exercise. By the time you feel thirsty you are already dehydrated. You need to have a plan to maintain your fluid intake.

Using a fluid plan during your marathon training will influence how well you can train and will give you the opportunity to practice your fluid plan for competition. You cannot train your body to get used to dehydration! You can train yourself to drink fluids regularly before, during and after exercise to prevent dehydration.

Fluid loss of only 2% of body weight can reduce your performance by up to 20%.

How much fluid do you need?

Before marathon training: drink as much fluid as is comfortable (30-500 ml). In the 10-15 minutes before you train, your urine should be pale.

During marathon training: you need to drink the same amount as your body is losing. Fluid loss tends to be very individual. Your fluid intake should be spread out over the hour, for example, 250 ml every 15 minutes.

Work out your exact fluid needs by weighing yourself before you exercise and then again after you exercise. A 1 kg loss in weight means you have lost about 1 litre in sweat. Record the amount of fluid you drank while exercising and add to the amount of fluid lost. This is the total volume of fluid you need for similar training sessions. Weigh yourself in light clothing with sweat dried off to make the results more accurate. Use the same set of scales on a firm surface.

Follow the example below then work out your fluid need during marathon training:

Example: You had a 90 minute marathon training run. Your weight before training was: 85 kg After training your weight was: 84.25 kg So you lost: 0.75 kg during training (750 ml fluid) You had half a drink bottle of water during training: 450 ml Total sweat loss = 1200 ml (1.2 kg) % body weight lost = 1.2 kg/85 kg x 100 = 1.4%

So for similar marathon training sessions you need to drink 1200 ml of fluid. You should try and spread this over the session, for example, 200-250 ml every 15 minutes.

What about your fluid needs after training?

Follow the example and then work out your fluid needs after marathon training:

Example: In training for your marathon, you decide to have two training runs in one day. Your weight before your first session was: 65 kg Your weight after your first session was: 63.9 kg Total fluid loss = 1100 ml sweat during training (1.1 kg) % body weight lost = 1.1 kg/65 kg x 100 = 1.7%

To fully replace fluid losses before your next training session you need to drink 1650 ml (1100 ml (fluid lost) x 1.5 = 1650 ml)

Hints to help you replace your fluid losses after marathon training:

Have a variety of drinks, for example, one drink bottle with cold water and another with a sports drink.

Ask one of your training partners, friend or family to remind you to drink.

Which fluids are the best?

Sports drinks

A sports drink with 4-8% (40-80 g/l or 4-8 g/100ml) carbohydrate and 500-700 mg/l (20-30 mmol) sodium is generally recommended. Most sports drinks contain recommended carbohydrate levels, but not all meet or are close to meeting the recommended sodium content. So when choosing a sports drink, pick one that is close to the recommended sodium levels and meets your specific needs. For long distance events like marathons (and especially ultramarathons) and in extra heat it is best to choose a sports drink with the recommended sodium levels to guard against hyponatremia (an imbalance of body water and sodium).

Did you know that sodium has several important roles in sports drinks?

Sodium: - Enhances glucose and water absorption from the gut. - Maintains fluid balance. - Enhances fluid retention (ie: you don�t urinate as much). - Makes you want to drink more, which is good!

What is Sodium? Sodium is a mineral, an essential nutrient found in most of the foods we eat. The largest source of dietary sodium comes from sodium chloride or table salt. It helps to maintain blood volume, regulate the balance of water in the cells, and keeps nerves functioning. The kidneys control sodium balance by increasing or decreasing sodium in the urine. One teaspoon of salt contains about 2,300 milligrams of sodium, more than four times the amount the body requires per day.

Most Americans consume far more sodium than their bodies need. Many foods contain sodium naturally, and it is commonly added to foods during preparation or processing or as a flavoring agent. Sodium is also found in drinking water, prescription drugs and over-the-counter medications.

In the United States, about one in four adults have elevated blood pressure. Sodium intake is only one of the factors known to affect high blood pressure, and not everyone is equally susceptible. The sensitivity to sodium seems to be very individualized. Usually, the older one is the more sensitive they are to salt.

Drinks with higher levels of carbohydrate can increase the risk of dehydration as the reduce fluid absorption.

Try different sports drinks, as there are many brands with different flavors and compositions.

Water

Fruit juices and cordials

Milk and liquid meal replacements

Soft drinks / sodas

Caffeine-containing drinks (tea, coffee, energy drinks and some soft drinks)

Tea and coffee do not contain any carbohydrate unless sugar is added. Tea and coffee are not good rehydration fluids as they contain caffeine unless labeled as caffeine-free.

Energy drinks (eg: Red Bull) contain 12-15% carbohydrate, and caffeine, making them a poor choice as a rehydration fluid.

Some soft drinks like colas and Mountain Dew contain caffeine.

Scientific sports drinks

Alcohol

Alcohol impairs sporting performance by causing: - Decreased reaction time. - Problems with movement, balance, coordination, accuracy, concentration and effective decision making. - Blurry eyesight. - Changes in attitude. - Dehydration (alcohol is a diuretic) - Nausea and headaches. - Early fatigue. - Impaired temperature control. - Interference with glycogen synthesis post-exercise. - Delayed healing of soft tissue injuries. - Weight gain.

Guidelines for sensible alcohol intake

If you are injured while exercising, avoid alcohol for at least 24 hours. Alcohol causes more blood to flow to the injured area, increasing swelling and bleeding, which may slow recovery or make the injury worse.

When you are competing you want to be in peak form, so avoid alcohol for at least two days before the event.

When you do drink, keep it to no more than two standard drinks each day for women or three standard drinks each day for men.

On any one drinking occasion, drink no more than six standard drinks for men or four standard drinks for women. A standard drink is one glass of beer or one glass of wine or one pub measure of sprits.

Iron

Why do you need iron?

Iron deficiency and iron deficiency anaemia

How do I know if I have iron deficiency?

How can I prevent iron deficiency?

The recommended daily intake of iron is:  Adolescents (12-18 yrs): 10-13 mg/day  Women (19-54 yrs): 12-16 mg/day  Pregnant women: 22-36 mg/day  Women (54 + yrs): 5-7 mg/day  Men (19 + yrs): 7 mg/day

Marathon runners may have higher iron needs due to blood losses from bleeding in the gut and red cell destruction. Marathon runners, especially females, should aim for the upper range of the recommended daily iron intake, and have their blood iron levels checked regularly.

Which foods contain iron?

Haem iron is a rich source of iron easily absorbed by the body. Haem iron is found only in animal foods such as meat, fish, shellfish and poultry. The redder the meat the higher the iron content.

Non-haem iron is found in plant foods. Non-haem iron is not as readily absorbed as haem iron due to the following inhibiting factors:  Phosphoric acid (found in legumes, wholegrains and soy products).  Phytic acid (found in unprocessed bran, oatmeal and wholegrains).  Oxalic acid (found in spinach, silverbeeet, rhubarb and soybean products).  Tannic acid (found in tea and, to some extent, coffee).

The absorption of non-haem iron can be improved by the following enhancing factors:  Ascorbic acid (vitamin C). You can improve iron absorption by eating iron-containing foods with foods containing vitamin C.  Meat (meat contains a factor which boosts iron absorption). You can improve iron absorption by eating meat with non-haem iron sources.

Practical tips to improve iron absorption:

 Include lean red meat in your meals three to five times each week (the red meat provides iron and increases the absorption of haem and non-haem iron in the meal).

 If you are not having a haem iron-containing food in your meal, include a good source of non-haem iron.

 Include foods containing vitamin C with your meal, for example, have a drink of fruit juice or piece of fruit. Examples of food containing vitamin C include: citrus fruit, (oranges, mandarins, grapefruit, lemon), fruit juice, kiwifruit, feijoas, cauliflower and broccoli, green peppers, tomatoes.

 Avoid tea and coffee in the one or two hours around meals.

 Look for foods fortified with additional iron, for example, some breads and cereals (look at the list of ingredients to see if processed foods contain iron).

The facts about iron supplementation

In the long term, food is the safest and healthiest way to maintain iron status.

Frequent use of iron supplements can have adverse effects.

What could happen if you use iron supplements all the time?

You may get iron build-up in your tissues, leading to toxicity.

You may get greater free radical damage.

You may experience diarrhoea or constipation, stomach discomfort, nausea and an increased risk of infection.

The fallacies about iron supplementation:

- Iron supplementation will not make up for an inadequate diet!

- Iron supplementation will not improve your performance unless you have iron deficiency anaemia.

Calcium

Why do you need calcium?

Insufficient dietary calcium can contribute to stress fractures in the short term and osteoporosis or thinning of the bones later in life, especially in females.

By reaching a good peak bone mass in your twenties you can help reduce your risk. After peak bone mass has been achieved, it is important to try to maintain bone mass.

Meeting recommendations for calcium intake combined with exercise, will help achieve and maintain peak bone mass. For women, regular menstrual periods also play an important part in developing and maintaining peak bone mass.

Recommended intake of calcium:  Adolescents � 1000-1200 mg/day  Adults (males and females) � 800-1000 mg/day  Post-menopausal women � 1000-1200 mg/day

You can meet you daily requirement for calcium by including calcium-rich foods in your daily diet.

If you do not eat dairy products or have a low-energy intake, you need to take special care that your diet is providing adequate calcium.

Calcium content of foods

How do you put it all together to plan what you will eat and drink for training?

Make sure you are meeting your basic fluid needs as well as increased fluid needs when training.

A good guide to meeting your needs is a stable body weight and satisfying your appetite.

Once you have planned your marathon training diet you will be able to adapt it to meet your body�s needs during different phases of training.

Your training nutrition is changing constantly so keep an eating record and check this every six to eight weeks to ensure you are meeting all of the nutritional recommendations.

The checklist below will show you where you are at with your training nutrition. After you have filled out your eating record go through the checklist and identify where you are not meeting the recommendations. Set goals for improvement.

Checklist for training nutrition

 Did you have breakfast? Yes / No  Did you have lunch? Yes / No

 Did you have dinner? Yes / No

 Did you eat carbohydrate in the 2 hours before training? Yes / No

 Did you eat carbohydrate and protein within half to one hour after training? Yes / No

 Did you have 6-8 cups of fluid? Yes / No

 Did you have extra fluid before/during/after training? Yes / No

 Did you have enough serves of carbohydrate to meet your needs? Yes / No

 Did you have enough serves of protein to meet your needs? Yes / No

 Did you have enough serves of food containing iron to meet your needs? Yes / No

 Did you have enough serves of food containing calcium to meet your needs? Yes / No

Main points for the diet of marathon runners

Carbohydrate provides the most readily available superior source of fuel or �energy� for muscles to use. Marathon runners should consume 55-70% of their energy from carbohydrate (5-10 g per kg of body weight per day), depending on their sport.

Protein provides the body�s building blocks. Marathon runners should consume 15% of their energy from protein (0.8-1.7 g per kg of body weight per day), depending on their sport.

Fat provides the body�s most concentrated energy source. Marathon runners should try to keep their fat intake low.

Fluids are essential to regulate temperature and prevent dehydration. Athletes should drink fluid before, during and after exercise. There are many fluids athletes can choose. Sports drinks are specifically designed for efficient rehydration. The optimum composition for sports drinks is 4-8% carbohydrate and 500-700 mg/litre of sodium.

Iron is an essential element. A well planned diet will provide sufficient iron.

Calcium intake is important to ensure peak bone mass and maintenance of strong bones.

How do you put it all together to design a nutritional plan for marathon training? Start with three main meals and snacks and check that you have included enough carbohydrate, protein, fluid, iron and calcium to meet your needs.