2.1 Diet and Nutrition

Calories for men

2500

Calories for women

2000

Components of a diet

55% carbohydrates

15% protein

30% fats

5 portions of fruit and beg

Carbohydrates

• sugars and starches stored in the body as glycogen and converted to glucose to fuel energy production

• preferred fuel for exercise - 75% of energy requirements

Carbohydrates - starches

• rice, potatoes

• stored as glycogen in the liver and muscles

Carbohydrates - sugars

• fruit, honey

• circulate in the blood stream as glucose

Protein

• amino acids essential for the growth and repair of cells and tissues

• make muscle proteins - increases muscle size

• make haemoglobin

• make enzymes, antibodies, and collages

  • enzyme - biological catalyst which increases the speed of chemical reactions

• can also be used as a fuel when carbohydrates and fats are depleted

Fats

• triglycerides which provide the body with fatty acids for energy production

• insulate nerves, form cell membranes, cushion organs

• provide an energy store - broken down for aerobic energy production and have twice the yield of carbohydrates

Fats - unsaturated

• typically liquid at room temperature

• help lower cholesterol

  • avocado, olive oil

  • can boost the delivery of oxygen, improve endurance recovery, reduce joint inflammation

Fats - saturated

• typically solid at room temperature

• can be associated with CV disease

  • butter, bacon

  • intake should be limited to reduce the risk of cardiovascular disease

Calcium

• bone health, muscle contraction, nerve transmission, blood clotting

Iron

• formation of haemoglobin, enzyme reactions, immune system

Phosphorus

• bone health, energy production

Vitamin A

• antioxidant properties, eye health

Vitamin B

• breakdown of food, haemoglobin formation, skin and eye health

Vitamin C

• skin, blood vessels, soft tissues

Vitamin D

• bone health, protection against cancer and heart disease

Vitamin E

• antioxidant properties, skin and eye health

Vitamin K

• blood clotting, bone health

Fibre

• fibre is essential for the function of the large intestine - found in fruit, cereals, lentils, vegetables

• adequate fluid intake allows fibre to work properly

Water

• water is essential for hydration - before, during, after exercise

• two-thirds of body weight is water

• dehydration can result in decreased plasma volume, decreased SV, increased temperature, and increased HR

Energy

• ability to perform work, measured in joules or calorie

Too few calories

• atrophy

• decreased intensity and duration of performance

• increased risk of fatigue, injury, and illness

Energy expenditure

• BMR + TEF + physical activity energy expenditure

  • BMR = minimum amount of energy required to sustain essential physiological function at rest - can be up to 75% of energy expenditure

  • TEF = energy required to eat, digest and absorb food

Energy balance

• energy in < energy expenditure - weight loss

• energy in = energy expenditure - weight maintenance

• energy in > energy expenditure - weight gain

Anabolic steroids

• increases muscle mass and strength, increases recovery, increases intensity of training

• irritability, mood, liver damage, heart failure

• can treat muscle wastage diseases, used by weightlifters or sprinters

Erythropoietin (EPO)

• increases RBC count, increases O2 transport and aerobic capacity

• increases blood viscosity, decreased cardiac output, increased risk of blood clots

• difficult to detect - some athletes have naturally higher RBC levels, used by endurance athletes

Human Growth Hormone (HGH)

• increased muscle mass and strength, increased fat metabolism, increase blood glucose

• abnormal bone and muscle development, enlarged organs, higher risk of cancer and diabetes

• used by any type of athlete

Blood Doping

• increased RBC level, increased O2 transport, increased intensity and duration

• increased blood viscosity, decreased cardiac output, increased risk of blood clots, risk of infection

• used by endurance athletes

Intermittent Hypoxic Training

• interval training under low oxygen conditions

• allow for acclimatisation, increased RBC level, increased mitochondria and buffering capacity so delayed OBLA

• benefits lost when training stops, can disrupt training patterns, decreased immune system function, dehydration

• used by endurance athletes

Cooling aids

• reduce core body temperature, decreased sweating and dehydration, decreased swelling and pain, decreased DOMS

• difficult to perceive exercise intensity, can cause ice burns, can make injuries worse, dangerous for people with heart and BP issues

• used by any athlete

Carb loading

• day 1 intense exercise to deplete stores, day 2-3 high protein/ fat diet, day 4 intense exercise, day 5-7 high carbohydrate diet

• increased glycogen stores, increased endurance, increased time to exhaustion, delays fatigue

• can cause hypoglycaemia and poor recovery rates, gastrointestinal issues, can impact mental preparation

• used by endurance athletes - ensures the is enough glycogen for aerobic glycolysis

Pre-event meal

• 3 hours before low GI (glycaemic index) food, 1-2 hours before high GI food

• maintains liver glycogen, maintains blood glucose levels

• can cause the body to counteract high glucose levels and cause the athlete to become dizzy/ fatigued

• used by all athletes

During event meal

• maintains liver glycogen, maintains blood glucose levels

• can be difficult to eat during activity, must be pre-planned

• energy gel in a marathon, banana at the end of a set in tennis

Post-event meal

• carbohydrates ideally within 30 minutes of finishing, and then every 2 hours until 6 hours after

• promotes faster recovery rates

• not always practical or possible

• used by all athletes

Hypotonic drink

• lower concentration of glucose than blood - prolonged exercise

Isotonic drink

• equal concentration of glucose to blood - events over 1 hour

Hypertonic drink

• higher concentration of glucose than blood - used during recovery, not exercise as it can increase dehydration

Creatine supplements

• increases PC stores

• more fuel for high intensity exercise, increased maximum and explosive strength

• increased weight gain, muscle cramps and gastrointestinal issues

• used by power athletes - weight lifters and sprinters

Caffeine

• stimulates the CNS

• increased concentration, increased metabolism of fats, increased endurance performance - preservation of muscle glycogen

• diuretic - dehydration, insomnia, anxiety, gastrointestinal issues

Bicarbonate

• neutralises a rise in acidity in the bloodstream

• increased buffering capacity, increased tolerance to lactic acid, increased intensity and duration

• gastrointestinal issues, unpleasant taste - nausea

Nitrates

• decreased BP, increased blood flow, delays fatigue

• headaches, dizziness, possible carcinogenic