The Energy Demands of Soccer
Soccer is one of most physically demanding of all sports. During a ninety-minute game a player can burn as many as 1500 to 2000 calories. A study from Holland found that elite male soccer players expended about 3400 calories a day on average.
Vigorous training and competitive games increases the energy needs of professional and amateur soccer players. Failure to meet those increased energy needs, especially with the right quality of nutrition, significantly increases the risk of impaired training status - i.e. you don’t get the results you deserve!
MACRONUTRIENTS, CARBOHYDRATE, FAT & PROTEIN
Weight for weight carbohydrates contain the least amount of energy out of the three macronutrients. Yet they are the most important type of fuel to a soccer player.
During short, intense bouts of exercise (like sprinting), carbohydrate is the only fuel capable of supplying the body with energy quickly enough. In the first few minutes of any activity, it is carbohydrate that almost exclusively meets energy demands. In addition, the ability to repeat a sprint at the end of a game to the same high level as at the start of the game relies, in part, on the body’s carbohydrate stores.
Although the body does use fat for lower intensity activity, carbohydrate acts as a "primer" or catalyst for fat to be broken down. Finally, carbohydrates play a key role in central nervous system function. The brain for example, uses glucose almost exclusively as its fuel.
Can diet significantly affect the body’s carbohydrate stores?
The average person has about 2000 calories of stored carbohydrate. An overnight fast (8 to12hrs) and a low-carbohydrate diet can dramatically lower these stores. More importantly, a carbohydrate-rich diet can more than double them. The body’s upper limit for carbohydrate storage equates to about 15 grams per kilogram (2.2lbs) of bodyweight. So an 80kg (175lb) person can potentially store up to 1200 grams of carbohydrate or 4800 calories worth of energy - all with just a few dietary modifications. There are different types of carbohydrates. Understanding what they are and how they affect the body differently is important to soccer players and what they eat before and after a game.
Fat contains more than twice the amount of energy as carbohydrate. A single gram contains nine calories making it a valuable source of fuel for longer duration activities. While fat cannot supply energy quickly enough for very intense activity, it can be used by the body to power lower intensity exercise such as jogging and walking. Fat also provides insulation and protection to vital organs such as the heart, lungs and liver and transports vitamins throughout the body. Not all dietary fat is the same. Like carbohydrate, fat can be broken down into several different groups:
Saturated fats are found in foods such as red meat, egg yolks, cheese, butter, milk and commercially prepared cakes, pies and cookies. The typical western diet consists of almost 40% total fat. Of this, 15% is made up of saturated fats, which is considered a major cause of coronary heart disease, diabetes and other major diseases. No more than 10% of the diet should come from saturated fats.
Unsaturated fats come in the form of monounsaturated fats and polyunsaturated fats. Monounsaturated fats can actually lower the risk of coronary heart disease and are found in foods like olive oil, canola oil, avocados, almonds and pecans.
Polyunsaturated fats, found in sunflower oil, safflower oil and corn oil are not thought to contribute to heart disease but don’t offer the same protection as monounsaturated fats.
Essential Fatty Acids
Essential fatty acids are a class of polyunsaturated fats that have received a lot of attention in the media recently. They are thought to be cardio-protective and may help prevent a range of other illnesses. There are three types of essential fatty acids – Omega 3, Omega 6 and Omega 9. Omega 3 and Omega 6 must be consumed while the body can produce some Omega 9 on its own. Essential fatty acids are required for healthy cardiovascular, reproductive, immune, and nervous systems. Found in foods like walnuts, pumpkin seeds, Brazil nuts, sesame seeds, avocados, some dark leafy green vegetables and oily fish, the typical Western diet is often deficient of essential fatty acids.
Despite its bad press, cholesterol is actually essential for many important bodily functions. There are essentially two types of cholesterol – low-density lipoprotein (LDL) and high-density lipoprotein (HDL). LDL is known as the “bad” cholesterol because it carries and then deposits cholesterol at the artery walls. HDL on the other hand, is known as “good” cholesterol because it acts as a scavenger removing cholesterol from artery walls and transporting it to the liver to be excreted.
Although some foods like cream, butter, ice cream, egg yolks, shellfish and red meats contain cholesterol, it’s a high intake of saturated fat that causes the body to synthesize too much cholesterol. The maximum amount of dietary cholesterol recommended each day is 300mg.
Correct and adequate protein intake is crucial for anyone involved in vigorous training. Protein is essential for the growth and repair of skin, hair, nails, bones, tendons, ligaments and muscles. It also serves a crucial role in enzyme production and maintaining a strict acid-base balance.
The Recommended Dietary Allowance (RDA) for the average male and female adult is just 0.83 grams per kilogram (2.2lbs) of bodyweight. In a 70kg (154lb) individual this equates to just 58 grams of protein per day or about two chicken breasts worth.
Some research shows that competitive athletes, particularly those involved in heavy weight training, may require more protein. The recommendation for strength and endurance athletes ranges from 1.2 to a maximum of 2.0 grams per kilogram. Research has shown that consuming more protein than this serves no benefit and may be harmful in the long term.
Good sources of protein include low fat milk, poultry, fish, lean red meat, eggs, nuts, beans and lentils and soy products. Fatty meats like pork and fast food hamburgers as well as most cheeses contain a lot of saturated fats so are not as suitable sources of protein.
Recently, the emergence of high protein, low carbohydrate diets have become popular in the weight loss industry. While they may or may not help to shed
the pounds, high protein, low carbohydrate diets are unsuitable for soccer players. Many athletes are afraid that their heavy training schedule will force their bodies to breakdown lean muscle mass and then use it as energy. The body does use protein sparingly as a source of fuel after 45 minutes of exercise; however consuming more protein is not a good strategy.
1.4 The Soccer Player’s Diet
A typical western diet contains too much fat and not enough healthy, whole grain carbohydrates. Soccer players should aim to make 60-65% of their diet carbohydrate, with an emphasis on fresh fruit and whole grains such as brown rice and pasta, wholemeal bread, potatoes and high fibre cereals.
About 20- 25% of total calories should be in the form of fat. The majority of this should be in the form of good fats (monounsaturated, polyunsaturated, omega fatty acids) found in oily fish like mackerel and salmon, olive oil, avocado and raw nuts (not roasted or salted).
Protein should make up the remaining 10-15% of a soccer player’s diet derived from fish, poultry, low fat milk and lean red meat for example.
Ideal Diet Composition for a Soccer Player
|Average Western Diet||Ideal Soccer Players Diet|
Sample Day’s Diet for a Soccer Player in Training
Piece of fruit
Bowl of oatmeal or porridge (sweeten with dried fruit or honey)
3-4 slices wholemeal bread toasted with small amount of butter/olive oil spread, jelly/jam
Glass of fresh fruit juice (not concentrated)
Snack Piece of fresh fruit
2-3 fig biscuits/cookies
Tuna or grilled chicken
Bagel, baguette etc. (preferably wholemeal)
Mixed salad with olive oil and lemon juice dressing
Glass fresh fruit juice or low fat milk
Low fat or bran muffin
Snack Bag of nuts and raisins (such as almonds, pecans, Hazelnuts etc)
Large serving rice or pasta
Grilled fish, chicken or lean beef mince
Large mixed vegetable salad with dressing
Small serving of ice cream and strawberries
This is one sample day only and a wide range of foods should be eaten. Try
also to drink 2 litres (68 oz) water each day (fluids as part of a sports drink
Vitamins and Minerals
Vitamins and minerals have an important role in the body. The facilitate energy release and are vital for optimum growth, development and repair.
Thirteen different vitamins have been identified and studied to date. There are classed as either fat-soluble (vitamins A, D, E, K) or water-soluble (vitamin
B complex, vitamin C). Together they are responsible for blood clotting, neuromuscular function, healthy skin, teeth and bones.
A well-balanced diet provides an adequate supply of all the vitamins regardless of age and level of physical activity. During periods of intense training, a natural increase in food intake supplies any extra vitamin demand the body may have.
Free Radicals, Antioxidants & Exercise
Free radicals are highly reactive molecules that can cause damage to the cells and are thought to accelerate the aging process and contribute to cancer, heart disease and diabetes. They are found in cigarette smoke, environmental pollution and some medications. Exercise may also increase the production of free radicals.
The body has an elaborate defence system against free radicals in the form of antioxidant enzymes. Vitamins A, C and E are known as antioxidant vitamins and can protect the cells against free radical damage. Although foods like citrus fruits, green vegetables and nuts contain antioxidant vitamins; some athletes feel the need to take a supplement due to the high level of training they undergo.
Although exercise is thought to increase free radical production, it also appears to increase the body’s antioxidant defence system at the same time. However, there is some research to suggest that a vitamin E supplement can reduce harmful free radical production associated with exercise. Whether this offers any overall health benefits is unclear.
Minerals account for roughly 4% of a person’s body mass. They provide the structure for forming bone and teeth. They also help muscles to contract, maintain normal heart rhythm and control the acid-base balance as well as other important bodily functions. Minerals are classed as either major or trace depending on how much is required per day. Major minerals include calcium, phosphorus, sodium, potassium and magnesium. Trace minerals include iron, zinc, copper, selenium and chromium.
The typical Western diet contains too little calcium. The RDA for calcium is 800-1000 mg for adults and 1200 mg for adolescents. The average adult consumes just 500-700 mg per day and for many it’s as little as 300 mg per day. Calcium deficiency can lead to a condition called osteoporosis – a weakening of the bones. Exercise actually helps to maintain healthy bone density.
Most adults consume too much sodium (found in abundance in processed foods), which can lead to high blood pressure. The RDA of 1100-3300 mg is equivalent to 0.5-1.5 teaspoons of table salt. Most people consume more than 2 teaspoons even when table salt isn’t used as seasoning.
Iron is helps the blood to carry oxygen so an iron deficiency (called anaemia) can lead to fatigue even with mild exercise. Some research has suggested that heavy exercise training creates an increased demand for iron. However, even in elite athlete supplements are unnecessary if the diet contains iron-rich foods.
Today’s elite soccer players follow a strict diet, particularly in on the day of a competitive match. While diet won’t
turn poor players into great players it can make the difference between playing poorly and playing to your full potential.
3.1 The Glycemic Index
Not all carbohydrate is digested and absorbed at the same rate. The Glycemic Index (GI) is a scale of how much a particular type of food raises blood sugar over a two-hour period compared to pure glucose. For example, a piece of food with a GI score of 45 means that it raises blood sugar 45% as much as pure glucose in that two-hour period.
Common sense says that simple sugars like fructose in fruit should have a higher GI than complex carbohydrates, but that’s not always the case. White
bread, white rice and potato have a very high GI. That means they raise blood sugar almost as much or even more than pure glucose. Fructose has medium GI because the fibre found in fruit slows digestion and absorption. Choosing foods with a high GI will help to quickly replenish carbohydrate stores after a game. Before a game low GI foods are more appropriate as they release energy more slowly and for a longer period.
3.2 Pre Match Eating
The goal prior to a game is to maximise carbohydrate stores in the muscles and liver and to top up blood glucose stores. Studies have shown that consuming foods with a high GI within an hour of exercise can actually lower blood glucose. The body produces an "overshoot" of insulin (which helps muscles to take up blood sugar). This in turn causes low blood sugar.
Soccer players should eat foods with a low to medium GI before a match. This allows for a relatively slow release of glucose into the blood and avoids the insulin surge. Consuming carbohydrate at least an hour before kick off allows any hormonal imbalance to return to normal. Example low GI foods include pasta, whole grain breads and rice, oatmeal, milk and milk products and fruit (except bananas and dried fruit).
The same is true for the pre-match meal. It might consist of pasta in a low-fat tomato sauce, baked beans or scrambled eggs on toast and fresh fruit such as apples, pears or orange juice. Some grilled fish or chicken and vegetables could accompany the carbohydrates. Ideally this meal should be eaten at least three hours prior to the start – especially if nerves are a factor, which can impair digestion.
Food in the stomach is given a high priority to be digested before it has chance to spoil. As a result greater blood flow is directed to the digestive tract - not good news when players’ muscles will soon be demanding an increase in blood flow too. The result of playing with a full stomach is nausea – the body’s attempt to cease exercise so that it can redirect blood flow back to the stomach.
There is one exception to consuming carbohydrate immediately prior to the start of a game and it’s in the form of a sports drink 5 or 10 minutes before kick off.
3.3 Post Match Eating
Outfield soccer players can use up 200 to 250 grams of carbohydrates during a game. It’s important that they replenish those stores as quickly as possible. It becomes even more important if players have more than one match in the week or are involved in heavy training. Ideally a large, high-carbohydrate meal should be eaten within two hours and it can and should consist of high GI foods. Bananas and dried fruits are good immediately following a match, as are
sandwiches and high-carbohydrate drinks like Gatorade Exceed and Lucozade. A main meal several hours later might consist of bread, pasta, potatoes and rice as well as other simple sugars like cakes and sweets.
Even under the best circumstances it can take over twenty hours to fully restore carbohydrate stores. This has implications for players who are training five or six days a week. In this case carbohydrate replenishment at regular intervals during training sessions becomes important. This is where high-carbohydrate drinks can offer a real advantage.
3.4 Carbohydrate Loading
Classic carbohydrate loading is often used by long distance athletes to “pack “ muscles with energy. The actual process involves depleting the muscles of carbohydrate a week or so before the event with exhaustive exercise and a low-carbohydrate diet. Two to three days before the even the athlete switches to a very high-carbohydrate diet. In their depleted state muscles take up more carbohydrate than they normally would giving the athlete a large store of energy.
For soccer, carbohydrate loading is unnecessary. In fact a disruption in a player’s normal eating pattern can actually cause stomach upset and lead to impaired performance. A more sensible approach to increase carbohydrate intake in the days leading up to a game.
Hydration and fluid replacement
Drinking before during and after a match serves two important aims – firstly it helps to prevent dehydration and secondly it can top up carbohydrate stores.
4.1 Preventing Dehydration
Soccer players can lose between 2-3 litres of sweat (oz) during a game, particularly in hot and humid conditions. They can also lose as much as 2-3 kg (4ó-6ó lbs) in bodyweight during a game. This amount of fluid loss will certainly have a negative affect on performance.
Ideally to counteract dehydration players should consume 200-400 ml (7-14 oz) of cold water or a suitable carbohydrate solution (see 4.2 below) 5 to 10 minutes before kick off. During the half time interval players should try to drink another 300-500 ml (10-17oz) of a sports drink. During hot weather or strenuous training sessions coaches should try to provide players with 150-250 ml (5-8oz) of drink about every 20 minutes.
Following a match or hard training session, it’s essential that lost fluids be replaced. Water on its own is fine but to replace fluid and replenish energy stores, a high carbohydrate drink may be more suitable.
4.2 Drinking Before & During a Match
The right carbohydrate drink taken before and during a game can postpone fatigue and stabilize blood sugar preventing light-headedness, headaches, nausea and "jelly-like" muscles.
However, not all carbohydrate drinks are created equal. Too much carbohydrate or sugar can actually hinder performance so it’s important. A solution that contains 40% carbohydrate empties the stomach much slower than plain water (which is 0% carbohydrate). It means that high sugar drinks such as Coca Cola, regular Lucozade, Exceed High Carbohydrate Source and Gator Lode (up to 40% carbohydrate) are NOT the best fluids to consume before or during exercise.
The ideal sports drink should contain 6-8% carbohydrate. It should also contain a small amount of salt. Sodium concentration in the blood can reduce due to sweating and drinking lots of diluted fluids. If it gets too low it can lead to nausea, headaches and blurred vision. Adding just a pinch of salt can offset this potential danger.
Sodium is also an electrolyte. Electrolytes help control the passage of water between body compartments and they also help to maintain the acid-base
balance of the body. Electrolytes (or lack of them) have been associated with muscle cramps in the latter stages of soccer games. Here are some effective sports drinks currently on the market suitable before and during a match or training session: Drink 200-400 ml (7-14oz) of a suitable sports drink 5 to 10 minutes before kick off but no earlier. During the half time interval drink another 300-500 ml (10-17oz). In hot climates try to drink 150-250 (5-8oz) ml every 20 minutes or so.
4.3 Drinking After a Match
Within two hours after a game you should aim to consume 100-200 grams of carbohydrate. Muscles are depleted of carbohydrate stores, which need to be replenished as quickly as possible. Sometimes it can be impractical or unpalatable to eat a large meal immediately afterwards. Carbohydrate drinks offer a convenient alternative. The sports drinks mentioned above are good but this is one of the few occasions when taking a high carbohydrate drink is beneficial. Fizzy drinks are okay but fruit juice is a more healthy option.
4.4 How to Make Your Own Sports Drink
You may have heard of “isotonic” sports drinks that have been “scientifically developed in conjunction with top athletes”.
It’s easy to make your own, low cost and equally as effective carbohydrate drink. Isotonic means a fluid containing electrolytes and 6-8% carbohydrate (such as the sports drinks in the table above).
To make your own add 200 ml (7oz) of concentrated orange juice (orange squash) to 1 litre (34oz) of water and add a pinch (.-ó teaspoon) of table salt.
Hypotonic is a fluid that contains electrolytes and a very small amount of carbohydrate. This is used in very hot conditions where fluid replacement is
the most important factor. To make your own add 100 ml (3.5oz) of concentrated orange juice to 1 litre (34oz) of water and add a pinch (.-ó
teaspoon) of table salt. Hypertonic refers to a fluid that contains a large amount of carbohydrate and is ideal for refuelling after a game. To make your own add 400 ml (13.5oz) of concentrated orange juice to 1 litre (34oz) of water and add a pinch (.-ó teaspoon) of table salt.
Quick Tips for Optimal Soccer Nutrition
Following a demanding training program increases the body’s need for
energy. Extra meals or nutritious snacks and drinks should be eaten to
provide enough fuel during strenuous conditioning periods.
· A soccer player’s diet should consist of about 60-65% carbohydrate, 20-25% fat and 10-15% protein.
· Carbohydrates should be predominantly in the form of fresh fruits and whole grains such as whole meal bread, pasta, potatoes and brown rice. Protein should come from lean meats, poultry, fish, pulses, beans and nuts.
· Saturated fat intake should be reduced in most cases i.e. full fat milk, cheeses, pastries, cookies, pies, fast food. Fat should not be omitted from the diet. Good fats are found in olive oil, avocados, nuts and seeds and oily fish such as mackerel.
· Adequate vitamins and mineral intake comes from a well-balanced diet. Supplementation is not needed in healthy individuals who eat a wide range of foods that includes plenty of fresh fruit and vegetables.
· The pre-match meal should be eaten at least 3 hours before kick off and should contain complex carbohydrates such as wholemeal bread or pasta, potato or rice. Fruit is good choice also.
· In the hour before a game no carbohydrates should be consumed, including carbohydrate drinks. However, 5-10 minutes before kick off,
200-400 ml (7-14oz) of a suitable sports drink can be taken.
· A suitable sports drink contains 6-8% carbohydrate. Fizzy drinks such as Coca Cola and Lucozade are not suitable. Gatorade and Lucozade Sport are good choices.
· During the half time interval another 300-500 ml (10-17oz) of a sports drink can be taken. In hot climates try to drink 150-250 (5-8oz) ml every 20 minutes or so.
· After a match try to consume as much carbohydrate in the first 2 hours as possible. High glycemic index foods like bananas, sandwiches and cakes will help to refuel muscles quickly. High carbohydrate drinks like concentrated fruit juice and even fizzy drinks offer a practical way to replenish carbohydrate stores
· Very few legal supplements can be backed up with credible scientific research. Those that can be supported include creatine monohydrate, caffeine, sodium bicarbonate and glutamine. While in some cases these supplements can improve performance, none are a magic potion and none can match the benefits derived from proper training and nutrition.
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