Sports med 2

How Our Bodies Use Food as Fuel  It takes hours to stock/restock the energy your muscles need!  Digestion Liquefied food is sent to the small intestine where its absorbed into the blood stream Macronutrients: CHO, protein, fat Micronutrients: vitamins, minerals Phytonutrients: fiber, water

How Our Bodies Use Food as Fuel  The CNS only runs on carbohydrate!  Carbohydrate All CHO is broken down into sugars & absorbed into bloodstream as glucose Stored in liver and muscle as glycogen High intensity exercise= muscles use only glucose to contract Athletes can consume high CHO diet to manufacture more glycogen storing enzymes

How Our Bodies Use Food as Fuel  Most whole/real food have a greater amino acid content than any supplement!  Protein Broken down into amino acids “building blocks” Can’t be stored in large amounts, better to eat small amounts during each meal, than one large amount Body prefers to use amino acids for growth, repair, and immune function instead of energy High intake can result in excess fluid loss and make you feel nauseated Amount needed is determined by weight, and sport Bodies can not use more than 2 g/kg of protein per day

How Our Bodies Use Food as Fuel  Fat Remains in the stomach longer, complicated to digest, not immediately ready for fuel CHO is needed to burn fat Dietary fat- needed for hormones, affects BP, inflammation and thickness of blood Body fat- part of cell membranes, nerve sheaths, protect and insulate Only burned for fuel during aerobic metabolism Intramuscular fat burned at moderate intensity exercise lasting 2 hours.

How Our Bodies Use Food as Fuel  Metabolism Process by which nutrients are broken down and utilized as fuel When energy is required fuel is metabolized

How Our Muscles Use Food as Fuel  Anaerobic Oxygen is not part of the metabolic process Glucose is the only fuel used Glycolysis produces ATP as a by-product ATP= true energy muscles use to contract Creatine helps recycle ATP for more energy  Aerobic Gives off more ATP energy, but you have to work at lower intensity Some protein can contribute but mostly fat and CHO are used

How Our Bodies Know When to Use Fuel through Hormones  Hormones = messengers produced by glands  Glands= direct changes that need to occur in body.  Changes can be anabolic (muscle building) OR catabolic (break down muscle)  Must have hormone homeostasis to use Fat, CHO & protein efficiently

HORMONES: Anabolic  Testosterone: aids in muscle building Stimulated by exercise but is variable depending on type and intensity High or low levels of fat content can negatively affect levels  Nutrient timing + Testosterone Food (small meal of pro & cho) MAY help move testosterone from blood into muscle. Not know for sure

HORMONES: Anabolic  Growth Hormone: promotes muscle growth with uptake of amino acids and glucose + breaks down fat tissue Stimulated by the hypothalamus. Affecting factors: ○ Stress, sleep, age, gender Factors that help release: ○ Sleep and protein

HORMONES: Anabolic  IGF-1 (insulin like growth factor) Stimulates cell growth and protects against cell death Stimulated by high diet in protein and CHO and growth hormone  Insulin: Is released by pancreas after eating to bind with glucose from food intake. Transports energy (glucose) from blood to muscles Stored in muscles as glycogen

HORMONES: Catabolic  Glucagon Released when blood sugar is low and muscles need energy Produced by pancreas but works opposite of insulin Glucagon signals liver, the liver releases glycogen (stored energy) into the bloodstream and goes to where it is needed (usually the brain and CNS) Considered catabolic because if no glycogen stored in liver it has to break down protein or fats to make new glucose.

HORMONES: Catabolic  Epinephrine & Norepinephrine (catecholamines): make sure brain and muscles have fuel Made by the adrenal glands Signal muscles to use glycogen for fuel, if that runs out they signal the liver to release glucose Their job is to release the fuel from the food eaten before activity to keep you going

HORMONES: Catabolic  Cortisol (stress hormone) Produced by adrenal gland under stressful situations (ie: prolonged exercise) Also used as an anti-inflammatory (activates cells) Breaks down proteins from cells and turn them into amino acids then send them to liver to produce glucose Works opposite insulin and decreases protein formation (bad for athletes). It is not part of the building of muscle but the breakdown Body should use food for fuel but will use Cortisol in emergency

Nutrient Timing Principles for Athletes  Aim for consistency  Go for Quality  Tune in to Timing

Nutrient Timing Principles for Athletes  Aim for Consistency…in fueling Scheduled meals AND snacks… ○ don’t starve your body/brain ○ Decrease risk of injury ○ Keeps energy levels consistent ○ Even calories = balanced cholesterol, blood sugar, insulin and cortisol levels!  Go for Quality  Tune in to Timing

Nutrient Timing Principles for Athletes  Aim for consistency  Go for Quality Times around activity are for fueling. ○ Bars, gels, sports drinks Meal times are for nutrition ○ Choose nutrient food: whole grain, fiber, protein, omega-3 fatty acids, fruits veggies  Tune in to Timing

Nutrient Timing Principles for Athletes  Aim for consistency  Go for Quality  Tune in to Timing It matters what, when and how much you eat See following slides

Before Exercise  CHO Taken 15 minutes before exercise spares glycogen depletion Choose pure CHO foods High glycogen + insulin = reduced cortisol  Protein Beneficial when taken with CHO before resistance training Need more research  Fat Slowly digested, do not eat close to exercise

During Exercise  CHO Intake has been shown to improve performance in all types of exercise Reduces risk of injury, and preserves protein Consume a mixture of sugars in low concentrate form in small quantities  Protein Intake during resistance training seems promising to reduce muscle tissue breakdown More research needed  Fat Not beneficial

After Exercise  CHO Restores energy, helps with immunity, decreases muscle breakdown 2 hours post exercise = fastest rate of glycogen storage Immediate recovery = High GI CHO g/kg body weight, repeat in 2 hours  Protein.1 to.2 g/kg body weight included in recovery food Limits muscle tissue breakdown & promotes muscle building  Fat Eat dietary fat at snacks & meals away from training.