Diet + Nutrition + Their Effect On Physical Activity + Performance Flashcards
Carbohydrates
2 types;
- simple = quickest source or energy + easily digested - found in fruits, processed foods + anything with refined sugars in.
- complex = found in nearly all plant-based foods + take longer for the body to digest. most commonly found in bread, pasta, rice + veg.
main fuel for high-intensity or anaerobic work. carbs are digested + converted into glucose which enters the bloodstream. glucose is stored in muscles + liver as glycogen, these stores are limited so refuelling is necessary.
Fats
- saturated fats = found in both sweet + savoury foods but mostly animal sources. too much leads to excessive weight gain which reduces stamina, flexibility + leads to health problems (eg coronary heart disease, diabetes, high blood pressure + atherosclerosis)
- cholesterol = found in blood. made predominantly in liver + is carried by blood as LDL + HDL (high/low density proteins). too much LDL leads to fatty deposits developing in arteries = negative effect on blood flow. too much HDL takes cholesterol away from parts of body where it has accumulated to liver where its disposed.
- trans-fats = artificial hydrogenated fats. can be found in meats + dairy products. allows food to have longer shelf life. can lead to high levels of blood cholesterol, heart disease + diabetes.
- replacing trans-fats + saturated fats with unsaturated fats important as fat is a major source of energy. used for low-intensity, aerobic work eg jogging but not aerobic as it needs oxygen to be broken down.
Proteins
made of amino acids, important for muscle growth + repair and to make enzymes, hormones + haemoglobin.
are a minor source of energy + tend to be used more by power athletes who have a greater need to repair and develop muscle tissue
Vitamins
helps allow to train maximally + recover quickly
- vitamin C = in green veg - protects cells, helps maintenance of bones, teeth, gum + connective tissues
- vitamin D = made by body when exposed to sunlight - helps absorb calcium, helps with phosphocreatine in mitochondria
- vitamin b1 = found in yeast, egg, nuts, red meat - help breakdown + release energy from food, keeps nervous system healthy
- vitamin b2 = dairy products, veg, eggs, fruit - helps breakdown + release energy from food, keeps skin, eyes + nervous system healthy.
- vitamin b6 = meat, fish, eggs, veg - helps form haemoglobin, helps body store energy from protein + carbs
- vitamin b12 = red meat, dairy products, fish - makes red blood cells + keeps nervous system healthy, releases energy from food
Minerals
calcium - needed for strong bones + teeth + efficient nerve + muscle contraction
sodium - helps regulate fluid levels, however too much linked to increase in blood pressure which increases risk of heart attack or stroke
iron - involved in formation of haemoglobin which transports oxygen + therefore improves stamina. lack of iron leads to anaemia
Fibre
source = wholemeal bread + pasta, potatoes, nuts, seeds, fruit, pulses + veg
important during exercise as it slows down time taken to break down food which results in slower release of energy.
aids digestion and prevent constipation
Water
60% of a persons body weight + essential for good health
transport nutrients, hormones + waste products and helps regulate body temp.
water keeps from overheating during exercise. water lost during sweating (which cools body down) which could therefore lead to dehydration
dehydration can result in;
- increased blood viscosity
- reduced sweating = overheating
- muscle fatigue + headaches
- decreased transportation of nutrients + waste products
- increased heart rate
- decreased performance, reaction time, decision making
Dietary supplements
- glycogen loading
- creatine monohydrate
- sodium bicarbonate
- caffeine
Glycogen loading
a form of dietary manipulation to increase glycogen stores over + above that which can normally be stored. its used for endurance performers which has 3 main methods;
1. 6 days before comp eat a diet high in protein for 3 days + exercises at relatively high intensity to burn of existing carbs. followed by 3 days high in carbs + light exercise. theory = by depleting glycogen stores it will increase up to 2x more than original amount
2. day before comp 3 mins of high intensity opens carbo window. replenishing glycogen stores during first 20 mins after exercise can enhance performance for next day. carbo window closes after 2 hours however first 20 mins is more effective.
3. non-depletion protocol - training intensity reduced the week before comp, 3 days before comp high carb diet is followed with light intensity exercise.
Pros + cons of glycogen loading
+ increases glycogen storage
+ increases glycogen stores in muscle
+ delays fatigue
+ increases endurance capacity
during carbo-loading;
- water retention = bloating
- heavy legs
- digestion problems
- weight increase
during depletion phase;
- irritability
- need to alter training programme through lack of energy
Creatine
used to increase phosphocreatine stored in muscle
phosphocreatine used to fuel ATP-PC system = provides energy
increasing creatine = increased ATP-PC system time lasted
helps improve recovery time
most beneficial for explosive events eg sprints, jumps + throws
Pros + cons of creatine
+ aims to provide ATP
+ replenishes phosphocreatine stores
+ allows ATP-PC system to last longer
+ improves muscle mass
- side effects eg muscle cramps, diarrhoea, water retention, vomiting
- hinders aerobic performance
- mixed evidence to show benefits
Sodium bicarbonate
can increase the buffering capacity of the blood so can neutralise effects of lactic acid + hydrogen ions.
concept behind drinking sodium bicarbonate solution = reduces acidity within muscle cells in order to delay fatigue + allow performer to continue at a high intensity for longer
Pros + cons of sodium bicarbonate
+ reduces acidity in muscle cells
+ delays fatigue
+ increases buffering capacity in blood
- side effects eg vomiting, pain, cramping, diarrhoea, bloated
Caffeine
naturally occurring stimulant
increases alertness + reduces fatigue
used by endurance performers who rely on aerobic system since fats are the preferred fuel for low-intensity, long-endurance exercises
can be found in coffee, tea, cola, chocolate, energy bars with caffeine + gel
