Body Composition and Nutrition

This part of the site is setup by Th.C. de Winter, MD Sports medicine, and has a lot of info on the relation between diets and body composition.

• Optimal body weight and composition
• Important function of nutrition
• Energy needs
• Vitamins and minerals
• Protein and amino acids
• Creatine
• Example dietary calculation
• Example snacks/sweets/alcohol

Optimal body weight and composition

An optimal body weight differs individually. Not every rugby player will have the same optimal weight. Estimation of this optimal body weight can be done by an easy calculation: body height (in cm.) minus 100 = ideal weight. A better and more precise way of estimation can be done while using the Quetelet index; this is body weight (kg.) divided by body height x body height (meter!), the result of this calculation should be between 20 and 23. Measurement of the skinfold thickness (body fat percentage) is the best way of examination the body composition. Reference values: < 30 year 15%, 31-39 years 17.5% and > 40 years 20%.

Examples: Player A 25 years of age: 170 cm, 80 kg and 30% fat percentage

• Height (m) minus 100 rule:
• Quetelet rule G/L2:
• Fat percentage (<15%):

• 70 kg (so 10 kg overweight)
• 27.7 kg/m2 (so 13.6 kg overweight)
• 30 %(so 12 kg overweight)

Player B 29 years of age: 180 cm, 75 kg en 14% fat percentage

• Height (m) minus 100 rule:
• Quetelet rule G/L2:
• Fat percentage (<15%):

• 80 kg (so 5 kg under optimal weight)
• 23.1 kg/m2 (so 0.3 kg overweight)
• 14 % (so 0.75 kg under optimal weight)

Conclusion: player A carries a higher total body weight and more ballast (i.e. fat tissue) which gives a lower aerobic condition and a lower agility.

Important function of nutrition

Food mainly exists out of carbohydrates, fat and protein. Each of them has its own specific function in the body. Carbohydrates can especially be found in rice, bread and potatoes. The main function of carbohydrates is carrying energy for body movement. Fat can be found in butter, cheese, chocolate and nuts while they are necessary as reserve energy and for building up cells and hormones. Protein occurs in meat and milk products and is important for muscle building. An optimal dietary division is 60% carbohydrates, 20 % fat and 20% protein. A regular way of eating gives the most optimal way of energy supply and the least storage of fat tissue.

Too much fat

Most Western European meals contain enough and protein. Most of the times too much fat are eaten and little carbohydrates. This surplus of fat is stored as fat tissues around the abdomen and can hardly be moved once arrived. You have to lessen food like french fries, pork meat, soft drinks, alcohol, candy, chocolate, pie and peanuts. Advisable are foods like lean beef, boiled fish, chicken or turkey, bread, buttered milk, water, coffee and tea without milk and sugar.

Energy needs

Daily energy needs by men is around 11.100 kJoule (2600 kcal). Being a referee in a rugby game demands extra energy: 30 kJoule (7 kcal) each kilogram of bodyweight each hour.

Example. Flanker 170 cm, 80 kg en 30% fat percentage

• Daily energy needs
• 1 rugby match (1.3 hours)
• Total energy needs

: 2600 kcal/day (11.100 kJoule/day)
: 742 kcal extra (3120 kJoule)
: 3342 kcal

Vitamins and minerals

A normal regular diet will fully take care of an adequate amount of vitamins and minerals. In case of doubt only take one multivitamin tablet once a day.

Protein and amino acids

Bodybuilders mainly take these. It's quite easy to take extra protein during a normal diet. A surplus of protein will be stored as fat. No positive effects of these supplements have been found on aerobic fitness or strength; besides these supplements are expensive, so don't use them.

Creatine

Creatine is in the highlights nowadays because of its positive effects on strength and explosive power. It's not on the IOC doping list. Look here for more information on using creatine.

Need for fluids

Beside adequate nutrition at least 1-2 liter of water is necessary to make sure that all body processes function smoothly. During a match water is lost by sweating. It is important to restore this loss of water by enough and regular drinking. Loss of water can go up to 1 liter each hour. This can easily be measured by estimation of your body weight before and after a match. Especially during hot weather each moment of rest during a game must be filled with drinking. Maybe a "mobile drink bottle - as used in marathon and triathlon training - is a solution for referees. This bottle is worn in a belt at the back. Thirst quenchers like Extran, AA drink, Gatorade or Sport Energy are preferable.

A very simple way of checking if you did not drink enough and are perhaps dehydrated is by checking your urine colour. For this, you can download an urine colour chart.

Some tips

Prefer whole wheat bread and avoid fatty cheese and meats.

• Regular eating including breakfast is advisable, for in between use ginger bread etc.
• No daily use of the scale.
• Don't follow an extreme diet, this will only lead to failure of continuity.
• On the day of a match it is important to have a good breakfast with whole wheat bread, cereals, muesli combined with milk, fruit (apple and banana). So you have a good start of energy within your body, before starting the match.
• Eating just before a game will only lead to gastro intestinal problems.

In the next tables an optimal composed diet is shown as well as an overview of frequently eaten snacks, fast food and drinks meals. So it is easy to see how much extra and "unhealthy" (fatty) energy these foods contain.

Example dietary calculation

Example snacks/sweets/alcohol

So: one rugby match for a player of 80 kg is comparable to :

• 1 minced meat hot dog or
• 1/2 amount french fries or
• 3 glasses of beer

Last updated on 12-11-07