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Flashcards in Nutrition Deck (43):

What are the seven classes of food?

-Carbohydrates -Fats -Proteins -Fibre -Vitamins -Minerals -Water


What is the definition of a balanced diet?

A balanced diet contains adequate amounts of all seven groups.


Carbohydrates -What are all carbohydrates made up of?

-Chains of glucose molecules


Carbohydrates -When the chains are short...

When the chains are short, the carbohydrates are sugary to taste, e.g. the carbohydrates found in fruit, table sugar and chocolate. Simple sugars


Carbohydrates -When the chains are long...

Long chains of glucose molecules make up the starchy, more complex carbohydrates, e.g. in pasta, rice, bread and potatoes Complex sugars


Carbohydrates -How are they stored? -What happens when they are needed?

Carbohydrates are stored in the liver as glycogen and when they are needed they are broken down into glucose to be used in respiration.


Carbohydrates -What is there role?

The primary role of carbohydrates is for energy (particularly high intensity work). They are also essential for the nervous system to work properly


Carbohydrates -What is glycaemic index?

The number of glucose molecules in the carbohydrate not only determine what it is, but how hard it is to digest and how quickly it can release its energy. The Glycaemic index (GI) of food refers to how quickly it breaks down to release its energy.


Carbohydrates -How do sugary carbohydrates break down?

-Sugary carbohydrates break down much faster than starchy carbs as they are smaller molecules, and are said to be low GI.


Carbohydrates -How do complex carbohydrates break down?

Complex carbohydrates are high GI as they are made up of longer chains and so take longer to break down.



-How are they structured

Fats are made up of three fatty acid molecules attached to one glycerol molecule… 

During digestion the triglyceride is broken up into a glycerol and three fatty acids. When they are broken down they are used for energy.



-As fats are bigger molecules than carbohydrates they...

-need more oxygen to break them down and so

-can only be used for low intensity exercise.

-However, this also makes them very energy rich and they contain more than double the energy contained in carbohydrates.



What are the states of fats at room temperature?

Where are they derived from?

Fats can be saturated and unsaturated.

Saturated fats tend to be solid at room temperature and are found in animal products

Unsaturated fats tend to be liquid at room temperature and are derived from vegetable products (often called “oils”)



What are unsaturated and saturated fats important for?

Unsaturated fats are important for the transport of fat soluble vitamins and saturated fats are important for insulation.



Explain the health risks associated with a diet high in saturated fat

-Heart attacks





-High blood pressure



Cholestrol levels in terms of fats

It also leads to high cholesterol levels.

Cholesterol is made predominantly in the liver and is carried by the blood as

low density lipoprotein (LDL) and high-density lipoprotein (HDL).

Too much LDL can lead to fatty deposits developing in the arteries which can have a negative effect on blood flow. However, HDL takes cholesterol away from parts of the body where it has accumulated to the liver where it is disposed of.



-What are proteins made up of?

Chains of amino acid




-What do they provide?

-The 'building blocks' for tissue (muscle, ligaments, tendons)

-Growth and repair

-Produce enzymes, hormones & haemoglobin



What can they sometimes be used for?

Although they are not usually used for energy, they can be used when carbohydrate and fat stores are exhausted, e.g. in cases of starvation or extreme exercise such as ultra-marathons or iron man competitions.



A few facts about the consumption of proteins

When we consume food containing protein, the large protein molecule has to be broken down into the smallest units, amino acids, before it can be absorbed and used.

What the body builds from the amino acids depends on the body’s needs at the time. If you have been training and muscle fibres have been damaged, the amino acids will be rebuilt into muscle tissue (hypertrophy).



What food is fibre found in?

Whole meat, oats and in fruit and vegetables



Facts about fibre?

-It is the indigestible carbohydrate part of plants

-Provides no energy as we cannot break it down

-Adds bulk to faeces

-Reduces chance of constipation & bowel disease

-Binds to fats and cholesterol




Vitamins are chemical compounds required in only very small amounts. They play a vital role in energy production and metabolism

Generally, all the vitamins we require we can obtain through a well-balanced diet.

These are found largely in fresh fruit and vegetables.


Important vitamins

Vitamin B-12 –Makes RBC and keeps the nervous system healthy

B-complex–Release energy from food, healthy nervous system, eyes and skin heathy

Vitamin C–making blood vessels, skin & cartilage

Vitamin D–bone strength



These are also required in quite small amounts but play vital roles.

Many minerals are lost through sweating during exercise and should be replaced.


Important Minerals

Iron –makes up haemoglobin and myoglobin, which transport oxygen around the body and to the muscle cells

Calcium –Component of bones. Facilitates muscle contractions and nerve transmissions

Sodium (salt)–electrolytes which control the water balance in the cells



-Signs and symptoms

Dehydration occurs when fluid loss has a negative effect on performance. The signs and symptoms of dehydration include dizziness, headache, dry mouth, poor concentration, sticky oral mucus, flushed red skin, and rapid heart rate.


Facts about fluid loss

Fluid loss has a detrimental effect on performance; just 1% dehydration can cause a 5% drop in performance quality. At 4% the muscles capacity for work is severely affected and can cause a drop of up to 25%.



What are they?

Electrolytes are substances such as sodium, potassium, chloride and bicarbonate that dissolve in water have the capacity to conduct electricity. The balance of electrolytes is important for the normal function of cells and muscles. Together with calcium, magnesium, phosphate and sulphate, electrolytes are lost in sweat. If a lot of sodium is lost through sweat then the water balance inside the body’s cells is upset which dehydrates you further, leads to cramp and so has a detrimental effect on performance.


The effects of dehydration

·Water lost from blood plasma makes blood more viscous

·Consequently stroke volume decreases

·So heart rate has to increase (Cardiovascular drift)

·The body becomes less able to sweat

·Body temperature increases & performer may overheat

·Electrolytes are lost which causes cramp

·Oxygen is transported less efficiently




Keeping Hydrated


-Before taking part in exercise, athletes are advised to hydrate to compensate for any fluid loss which will occur during the exercise. Drinking 400-600ml in the preceding 2 hours will help.

-If your exercise period is less than about an hour & low intensity, just water is fine – you body doesn’t need any extra carbohydrate.

-Generally speaking, if you exercise regularly you should be drinking between 2.5 – 3 litres of water a day.

-By consuming fluid with sodium or salted snacks you will stimulate thirst and are more likely to retain the consumed fluid.


Keeping Hydrated

During event

During exercise, athletes should top up their fluid levels at every possible opportunity. If you wait until you feel thirsty it’s too late and you have started to become dehydrated.

The volume of fluid consumed during an activity to be sufficient to replace that lost through sweating and in urine production. A rough guide is about 1 litre every hour.

Elite athletes often weigh themselves before and after exercise to calculate how much fluid they have lost. Consuming drinks containing electrolytes will preserve sodium levels & help reduce dehydration.


Keeping Hydrated

Post exercise

Athletes should drink as steadily as possible for 1-2 hours after exercise, depending on what they have just done.

Plain water is not the best choice as it stimulates urine production, it makes you feel bloated reduces the drive to drink. Drinks containing sodium will stimulate thirst and assist the absorption of carbohydrate from the small intestine.

Consume 1.5l for every 1kg lost. Drink slowly and steadily rather than drinking a large volume at once.

Alcohol and fizzy drinks will just dehydrate you further and so should be avoided.


Dietary supplements/ Manipulation of diet

Glycogen Loading

-Used by who

Long distance

Endurance athletes


Dietary supplements/ Manipulation of diet

Glycogen Loading

Positive effects

-Increased glycogen storage

-Increased glycogen storage in the muscle

-Delays fatigue

-Increase endurance capacity


Dietary Supplements / Manipulation of diet

Glycogen loading

Negative Effects during carbo loading phase

During the carbo loading phase:

Water retention (bloating)

Heavy legs

Affects digestion

Weight increase



Dietary Supplements / Manipulation of diet

Glycogen loading

Negative effects during depletion phase

During the depletion phase:


Can alter training through a lack of energy


Dietary Supplements / Manipulation of diet


-Used by

Endurance athletes


Dietary Supplements / Manipulation of diet


Positive Effects

Stimulant which increases mental alertness

Reduces effects of fatigue

Improves mobilization of fats so improves endurance

Improves reaction time – can respond quicker to aspects on the track/pitch


Dietary Supplements / Manipulation of diet


Negative effects

Raises blood pressure



Loss of fine control

Against rules of most sports in large quantities


Dietary Supplements / Manipulation of diet


-Used by

Power or anaerobic athletes



Dietary Supplements / Manipulation of diet


Positive effects

Increases the amount of energy supplied from ATP-PC system

Able to perform maximally for longer

Improves muscle mass


Dietary Supplements / Manipulation of diet


Negative effects

Water retention



Mixed evidence to show positive benefits

Hinders aerobic performance