NUTRIENT TIMINGSports med 2

How Our Bodies Use Food as Fuel

It takes 24-48 hours to stock/restock the energy your muscles need!

DigestionLiquefied food is sent to the small intestine

where its absorbed into the blood streamMacronutrients: CHO, protein, fatMicronutrients: vitamins, mineralsPhytonutrients: 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 glycogenHigh intensity exercise= muscles use only glucose to

contractAthletes 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!

ProteinBroken down into amino acids “building blocks”Can’t be stored in large amounts, better to eat small amounts

during each meal, than one large amountBody prefers to use amino acids for growth, repair, and

immune function instead of energyHigh intake can result in excess fluid loss and make you feel

nauseatedAmount needed is determined by weight, and sportBodies can not use more than 2 g/kg of protein per day

How Our Bodies Use Food as Fuel

FatRemains in the stomach longer, complicated to

digest, not immediately ready for fuelCHO is needed to burn fatDietary fat- needed for hormones, affects BP,

inflammation and thickness of bloodBody fat- part of cell membranes, nerve sheaths,

protect and insulateOnly burned for fuel during aerobic metabolismIntramuscular 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 processGlucose is the only fuel usedGlycolysis produces ATP as a by-productATP= true energy muscles use to contractCreatine helps recycle ATP for more energy

AerobicGives off more ATP energy, but you have to work at

lower intensitySome 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 buildingStimulated by exercise but is variable

depending on type and intensityHigh or low levels of fat content can

negatively affect levels

Nutrient timing + TestosteroneFood (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, genderFactors 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

musclesStored 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 fuelMade by the adrenal glandsSignal 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 QualityTimes around activity are for fueling.

○ Bars, gels, sports drinksMeal 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 TimingIt 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 foodsHigh glycogen + insulin = reduced cortisol

ProteinBeneficial when taken with CHO before resistance

trainingNeed more research

FatSlowly 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 proteinConsume 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 1-1.5 g/kg body weight, repeat in 2 hours

Protein.1 to .2 g/kg body weight included in recovery foodLimits muscle tissue breakdown & promotes muscle

building Fat

Eat dietary fat at snacks & meals away from training.