NUTRITION AND SPORT
Introduction
For every physical activity the body requires energy and the amount depends
on the duration and type of activity. Energy is measured in kcal and is obtained
from the body stores or the food we eat. Glycogen is the main source of fuel
used by the muscles to enable you to undertake both aerobic and anaerobic
exercise. If you train with low glycogen stores you will feel constantly tired,
training performance will be lower and you will be more prone to injury and
illness.
A calorie (cal) is the
amount of heat energy required to raise the temperature of 1g of water 1°C
from 14° to 15°C. A kilocalorie (kcal) is the amount of heat required
to raise the temperature of 1000g of water
1°C.
Nutrient Balance
Carefully planned nutrition
must provide an energy balance and a nutrient balance. The nutrients are:
- Proteins - essential to growth and repair of muscle and other body tissues
- Fats - one source of energy and important in relation to fat soluble vitamins
- Carbohydrates - our main source of energy
- Minerals - those inorganic elements occurring in the body and which are
critical to its normal functions
- Vitamins - water and fat soluble vitamins play important roles in many chemical
processes in the body
- Water - essential to normal body function - as a vehicle for carrying other
nutrients and because 60% of the
human body is water
- Roughage - the fibrous indigestible portion of our diet essential to health
of the digestive system
What are the daily
energy requirements?
Personal energy requirement = basic energy requirements + extra energy requirements
Basic energy requirements
- For every Kg of body weight 1.3 kcal is required every hour. (An athlete
weighing 50Kg would require 1.3 * 24hrs * 50Kg = 1560 kcal/day)
Extra energy requirements
- For each hours training you require 8.5 kcal for each Kg of body
weight. (For a two hour training session our 50Kg athlete would require 8.5
* 2hrs * 50Kg = 850 kcal)
An athlete weighing 50Kg who trains for two hours would require an intake
of approx. 2410 kcal (1560 + 850)
Energy Fuel
Like fuel for a
car the energy we need has to be blended. The blend that we require is as
follows:
- 57% Carbohydrates (sugar, sweets, bread, cakes)
30% Fats (dairy products, oil)
- 13% Protein (eggs, milk, meat, poultry, fish)
The energy yield per gram
is as follows : Carbohydrate - 4 kcal, Fats - 9 kcal and Protein - 4 kcal.
(Note: 1 calorie = 1 Kcal)
What does a 50 kg athlete
require in terms of carbohydrates, fats and protein?
- Carbohydrates - 57% of 2410 = 1374 kcal - at 4 kcal per gram = 1374 / 4
= 343 grams
- Fats - 30% of 2410 = 723 kcal - at 9 kcal per gram = 723 / 9 = 80 grams
- Protein - 13% of 2410 = 313 kcal - at 4 kcal per gram = 313 / 4 = 78 grams
Our 50kg athlete requires: 343 grams of Carbohydrates, 80 grams of Fat and 78 grams of Protein
