Diet and nutrition 4.1 Flashcards
what are the seven food groups of a healthy diet
- carbohydrates
- fats
- fibre
- water
- protein
- vitamins
- minerals
what are the two types of carbohydrates?
- simple carbohydrates
- complex carbohydrates
what are simple carbohydrates?
- easily digested so are a rapid source of energy
- often found in process foods and anything with refined sugar added
- found in fruit
- good for quick energy replenishment e.g. between sets in a tennis game
what are complex carbohydrates?
- found in nearly all plant-based e.g. bread, pasta,rice
- take longer to digest due to being longer chains of glucose molecules resulting in a slower release of glucose into the blood and greater storage in muscles and liver
what type of exercise are carbohydrates the principle source of energy for?
high intensity and anaerobic work
how do carbohydrates provide energy?
they are broken down into glucose and enter the bloodstream. Then they are stored in the muscles and liver as glycogen (limited stores)
what is the glycaemic index?
- ranks carbohydrates depending on their effect on blood glucose levels
what does low glycaemic index mean?
- slower, sustained release of glucose into the blood meaning blood blood glucose levels are maintained for longer
- should be consumed 3-4 hours before exercise
e.g. beans on toast, pasta with a vegetable based source
what does a high glycaemic index mean?
- cause a rapid, short rise in blood glucose
- should be consumed 1-2 hours before exercise
e.g. fruit smoothies, cereal bars, yoghurt
what are unsaturated fats?
healthy fat which maintain levels of ‘good’ cholesterol
e.g. nuts, fish, avocados
what are saturated fats?
unhealthy fats which are usually from animal sources.
They contain LDL cholesterol which, if levels are too high, increase risk of heart disease and strokes
what are trans fats?
manufactured fats which are solid at room temperature
- directly linked to heart disease
- e.g. margarine, baked goods
why are unsaturated fats beneficial?
- they are a source of energy for low intensity, aerobic exercise allowing glycogen stores to be spared for higher intensity exercise
- aid the absorption of fat soluble vitamins (vitamins A,D,E,K)which keep the immune system healthy preventing time off training
why is too much fat in the diet bad for an athlete?
- causes weight gain and can lead to obesity:
-> limits agility
-> limits speed/power
-> limits stamina/endurance
-> limits flexibility - also can lead to high levels of blood cholesterol and lead to health problems such as coronary heart disease, diabetes and high blood pressure
function of protein:
- allow growth and repair of muscle and tissue growth (aiding muscular hypertrophy)
- also used to make haemoglobin (essential for any exercise)
- tend to provide energy when fat and glycogen stores are low (protein is a minor source of energy)
sources of protein
- fish, eggs, dairy products
what are vitamins?
essential nutrients which cannot be produced by the body and the body needs in small amounts in order to work properly
why can’t fat be used as energy for high intensity exercise?
Because it requires oxygen in order to be broken down into energy
function of vitamin D and where it can be found?
increased calcium absorption aiding strong bones and teeth
- main source is the sun but oily fish and dairy produce are sources
function of vitamin K and where can it be found?
helps to form proteins which are needed for blood clotting
- egg, liver oily fish, dairy foods
function of vitamin A and where can it be found?
important for vision and immune system
-eggs, leafy green vegetables, oily fish
function of vitamin E and where can it be found?
enhances immune system as it acts as an antioxidant
- vegetable oils
what are the water soluble vitamins?
vitamin C and B group vitamins
- need to be taken daily
function of vitamin C and where can it be found
- protects cells and keeps them healthy
found in green vegetables and fruit
function of vitamin B1 (thiamin) and where can it be found
- keeps the nervous system healthy and helps to break down and release energy from food
- found in yeast, eggs, nuts
function of vitamin B2(riboflavin) and vitamin B3 (niacin)
- help to break down and release energy from food
- keep skin, eyes and nervous system healthy
found in fruit, cereals, dairy products
function of vitamin B6 and where can it be found?
- helps to form haemoglobin
- helps the body to use and store energy from protein and carbohydrate in food
found in meat, eggs, fish, vegetables, bread
function of vitamin B12(folate) and where can it be found?
- releases energy from food
- makes red blood cells
- keeps the nervous system healthy
found in red meat, fish and dairy products
what are minerals?
- they assist bodily functions and tend to be dissolved in the body as ions called electrolytes
function of sodium
- helps with effective muscle contractions as it is an electrolyte (prevents cramps)
- maintaining fluids meaning it helps to prevent dehydration
function of iron
used in production of red blood cells (transportation of oxygen)
definition of balanced diet
a diet consisting of a variety of different food, providing adequate amounts of the nutrients necessary, for good health
function of calcium
bone and muscle health and is needed for muscle contractions
functions of water
- transports nutrients, waste products and hormones
- lubricates the joints, organs and eyes
- regulates body temperate through sweat evaporation (however this causes water loss which can lead to dehydration)
- keeps the blood viscous (aids oxygen delivery as blood can move around the body easier)
- cell function
definition of dehydration
occurs when the body is losing more fluid than it is taking in
effects of dehydration
- cannot cool the body down leading to overheating and feeling nauseas and the need to stop after initially reducing performance
- fatigue -> blood becomes more viscous so oxygen delivery slows
- increased heart rate
- deterioration in reaction time/ poor decision making
how to prevent dehydration
- wear appropriate clothing to slow down the rate at which body temp rises
- drink lots of water especially if doing lots of exercise as breathing rate increases and therefore more water is lost
how do electrolytes help to maintain hydration
they allow the uptake of water and maintain the correct rate of movement in and out of cells
impact of low electrolytes on performance
- could cause cramp -> may have to stop/performance levels decrease
- muscle weakness and fatigue -> decreased muscular endurance
- causing drowsiness and impairing decisions -> timing of decision may be wrong, whole decision could be wrong (as electrolytes conduct electrical impulses allowing the brain to work properly)
- could interfere with the nervous control of heart leading to an abnormal heart rhythm (electrolytes conduct electrical impulses allowing the heart t conduct properly)
what are supplements?
substances used to improve health and wellbeing or enhance performance.
- they can be legal or illegal
what is creatine monohydrate and how is it used/beneficial?
- increases phosphocreatine stores in the muscles meaning the ATP-PC energy system can last longer as the resynthesis of ATP can occur quicker and the athlete can work maximally for longer.
- it can also help to improve recovery times
possible side effects of creatine monohydrate
- muscle cramps
- diarrhoea
- water retention
- hinders aerobic performance
what are the benefits of taking sodium bicarbonate?
it is an alkali which neutralises the effects of lactate production (increases the buffering capacity of the blood) and therefore should delay fatigue and allows the performer to remain at a high intensity for longer.
- possible benefits for events where the lactic acid system dominates or where there is 30-90 seconds of maximal work
what are possible side effects of taking sodium bicarbonate?
- vomiting
- it also has limited effectiveness
benefits of taking caffeine for an endurance athlete
caffeine increases the use of fat for energy which aids an endurance athlete to maintain glycogen (which are limited) for harder parts of the race e.g. a hill or spring finish where higher intensity is needed. Called ‘glycogen sparing’
benefits of taking caffeine for a games player
- it is a stimulant so improves alertness, reaction time and decision making
possible side effects of taking caffeine
- dehydration
-insomnia (reduces recovery) - muscle and stomach cramps (hinders performance)
- loss of fine control
- large quantities are against the rules of most sports
how does glycogen loading benefit a performer?
- it maximises aerobic energy production which prevents endurance athletes from ‘hitting the wall’
at what intensity of exercise is glycogen used for ATP resynthesis
65% of max heart rate
what is method one of glycogen loading?
- a 6 day process including 3 days depletion (high protein, low carbohydrates and high intensity training) then 3 days replenishment (high carbohydrate and low intensity training)
benefits of method one of glycogen loading
- aims to fully deplete glycogen stores before replenishing them meaning they can be replenished by up to 2x their original levels -> called ‘supercompensattion’
cons of method one of glycogen loading
- could effect training as it is a 6 day programme
what is method 2 of glycogen loading?
- day before completion/performance
- athlete completes at least 3 minutes of high intensity training to open the ‘carbowindow’
what is the ‘carbowindow’?
a 20 minute period immediately after exercise when the body is most able to restore lost glycogen
what is method three of glycogen loading?
- 3 day process with no depletion stage
- training intensity is reduced the week before competition
- 3 days before competition a high carbohydrate diet is followed with light intensity exercise
benefits of glycogen loading
- increased glycogen storage
- increased glycogen store in muscles
- delays fatigue
- increased endurance capacity
cons of glycogen loading
during the depletion stage:
- irritability (could effect relationship with coach and therefore effect training)
- can feel the need to alter training programme due to lack of energy
during the replenishment stage:
- heavy legs (could affect level of training)
- affects digestion
- weight increases (particularly problematic for weight sensitive sports e.g.horse riding)
