Diet and Nutrition Flashcards
What are the 7 classes of food?
- Carbohydrates
- Fibre
- Fats
- Proteins
- Vitamins
- Minerals
- Water
What is a balanced diet?
Contains adequate amounts of the 7 food groups
What are carbohydrates made from?
Chains of glucose molecules
Describe short chained carbohydrates
- Sugary taste
- Found in fruit, table sugar, chocolate etc
Describe long chained carbohydrates
- Starchy
- More complex carbohydrates
- Bread, pasta potatoes etc
Where and how are carbohydrates stored in the body?
Stored in the liver as glycogen and when needed they are broken down into glucose to be used in respiration
What is the primary role of carbohydrates?
Energy at high intensities
What is glycaemic index (GI)?
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 of food refers to how quickly it breaks down to release its energy
What GI do sugary carbohydrates have?
High GI
What GI do complex carbohydrates have?
Low GI
What are fats made from?
3 fatty acid molecules attached to one glycerol molecule (triglyceride)
What is the primary role of fats?
Energy at lower intensities
Describe fats compared to carbohydrates
- Fats are bigger molecules than carbohydrates
- Need more oxygen to break fats down
- Only used at lower intensity work
- Very energy rich (contain more than double the energy contained in carbohydrates)
What are the two types of fats?
Saturated and unsaturated
Describe saturated fats
- Tend to be solid at room temperature
- Found in animal products
- Important for insulation
Describe unsaturated fats
- Tend to be liquid at room temperature
- Derived from vegetable products (oils)
- Important for the transport of fat soluble vitamins
Explain the health risks associated with a diet high in saturated fats
- Heart attacks
- High blood pressure
- Atherosclerosis
- Strokes
- Diabetes
- Cancer
- High LDL, Low HDL
What are proteins made of?
Amino acids
What do proteins provide for the body?
- The ‘building blocks’ for tissue (muscles ligaments etc.)
- Growth and repair
- Produce enzymes, hormones and haemoglobin
- Although not used for energy, they can be used when carbohydrate and fat stores are exhausted
What is hypertrophy?
Amino acids will be rebuilt into muscle tissue after training
What foods contain fibre?
- Whole-wheat
- Oats
- Fruit
- Vegetables
Describe 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 and bowel disease
- Binds to fats and cholesterol
What are vitamins?
- Chemical compounds required in only very small amounts
- Play a vital role in energy production and metabolism
- Generally, all the vitamins we require can be obtained through a well-balanced diet
- These are found largely in fresh fruit and vegetables
What is the function of vitamin B-12?
Makes red blood cells and keeps nervous system healthy
What is the importance of vitamin B-complex?
Release energy from food, healthy nervous system, keeps eyes and skin healthy
What is the importance of vitamin C?
Making blood vessels, skin and cartilage
What is the importance of vitamin D?
Bone strength
Describe minerals
- Required in small amounts but play vital roles
- Many minerals are lost through sweating during exercise and should be replaced
What is the importance of iron?
- Makes up haemoglobin and myoglobin which transport oxygen around the body and to the muscle cells
What is the importance of calcium?
- Component of bones
- Facilitates muscle contractions and nerve transmissions
What is the importance of sodium?
Electrolyte which controls water balance within cells
What are the effects of dehydration>
- Water lost from the blood plasma makes the blood more viscous
- Consequently stroke volume decreases
- So heart rate has to compensate by increasing (CV drift)
- The body becomes less able to sweat
- Body temperature increases and performer may overheat
- Electrolytes lost causing cramp
- Oxygen transported less efficiently
- Headaches/dizziness
How should a performer be hydrated 2 hours before an event?
Drinking 400-600ml
How should you be hydrated during an event?
- Roughly 1 litre every hour
- Consuming drinks containing electrolytes will preserve sodium levels and will help reduce dehydration
How should you be hydrated post-exercise?
- Drinking steadily for 1-2 hours after exercise, depending on activity
- Drinks containing sodium will stimulate thirst and assist the absorption of carbohydrates from the small intestine
Who would benefit the most using glycogen loading?
- Endurance athletes e.g. marathon runners, 10,000m runners
What are the positive effects of using glycogen loading?
- Increased glycogen storage
- Delays fatigue
- Increased endurance capacity
- Increased glycogen storage in muscles
What are the negative effects of glycogen loading?
During the carbo loading phase:
- Water retention (bloating)
- Heavy legs
- Affects digestion
- Weight increase
During the depletion phase:
- Irritability
- Can alter training through a lack of energy
Who would benefit the most using caffeine?
- Endurance athletes
What are the positive effects of caffeine?
- 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
What are the negative effects of caffeine?
- Raise of blood pressure
- Insomnia
- Dehydration
- Loss of fine control
- Against the rules of most sports in large quantities
Who would benefit the most using creatine?
- Sprinters
- Throwers
- Jumpers
What are the positive effects of using creatine?
- Able to perform maximally for longer
- Increases the amount of energy supplied from ATP-PC system
- Improves muscles mass
What are the negative effects of using creatine?
- Water retention
- Vomiting
- Diarrhoea
- Mixed evidence to show positive benefits
- Hinders aerobic performance
Who would benefit the most from using sodium bicarbonate?
- 400m runner
What are the positive effects of using sodium bicarbonate?
- Increases buffering of lactate so reduces acidity of blood
- Delays OBLA (fatigue)
- Enables performer to maintain intensity for a longer duration
What are the negative effects of using sodium bicarbonate?
- May cause vomiting, pain, cramping, bloating
What is the aim of glycogen loading?
- Raise muscle glycogen stores above their normal resting levels (supercompensation)
What activities would benefit most from glycogen loading?
- Low anaerobic and high aerobic activities
Describe the two parts to glycogen loading?
Depletion:
- Prolonged exercise to reduce levels of liver and muscle glycogen stores - at least 7 days before event
Repletion:
- A high carbohydrate diet in the period (3-4 days) before event
- Combined with light exercise or rest
- Also suitable for activities lasting 15-20 mins
- With a 2 day carbohydrate diet beforehand
In some circumstances, glycogen loading is very difficult for some elite performers, describe how it is possible for them to boost their carbohydrates the day before an event?
- Day before perform short (3 mins) high intensity exercise e.g. on an exercise bike
- The capillaries in the muscles widen and the ‘carb window opens’
- High carbohydrate intake within 20 mins
- As blood flow to muscles has increased, carbohydrates are transported directly to the working muscles and stored more readily
