WK 3 - DIGESTION, NUTRIENTS & DIET PLANNING FOR ATHLETES Flashcards
Energy of each macro?
Carbs: 17kj/g
Protein: 17kj/g
Fat: 37kj/g
Role of Carbs
- Energy source for all tissue.
- ESSENTIAL energy source for brain and red blood cells.
- Preferred fuel source for active muscles.
- Delays fatigue process
- Helps maintain performance for athletes working at high intensity.
play a role in recovery, where it’s important to replace the glycogen being used during activities which are going for >90mins. - Part of Ribose, a structural component of RNA and co-enzyme and Deoxyribose, a structural component of DNA.
- Involved in the immune system and blood clotting.
Types of carbs + their structures
Monosaccharides - Glucose, Fructose aka ‘fruit sugar’, Galactose
Dissaccharides - Lactose aka ‘milk sugar’ (Glucose + Galactose), Sucrose aka ‘table sugar’ (Glucose + Fructose), Maltose (Glucose + Glucose)
- Oligosachharides - Fructans (Fructose chains), Galactans (Galactan chains) found in wheat, rye and legumes
- Polysachharides - Starch (Glucose polymers, such as amylose and amylopectin), Glycogen and cellulouse
Fibre - undigested carbohydrate, usually oligosaccharides, polysaccharides, as well components of plant wall such as lignin
Carb food sources
Grains and cereals, fruit, starchy vegetables & legumes, milk & yogurt, sweets & sugars
Fibre also found in bran, nuts & seeds
What is Glycemic Index (GI)
How quickly carbs are digested and absorbed into the bloodstream to be used as energy.
Low GI?
- Longer to be absorbed & digested
- Avoid consuming later than 3hrs prior to training.
Eg. low GI foods?
Pasta, sweet potato, fruit, dairy, breads, grain.
High GI?
- Easily digested
- Consumed 30 - 60 mins prior to training.
Eg. high GI foods
Ripe banana, lollies, museli, dried fruit, energy bars / gels.
What affects overall glycaemic response
Amount of fat, protein and acid
Amount and types of fibre
Type of starch
Level of processing
Glycemic load?
= more accurate measure
Takes into account the anount of carbs in a serve of food.
Calculating glycemic load
GL = GI / 100 x CHO (g) per serving
Fats
Main energy source for low-intensity activities and endureance events.
- Fat reserves are required for energy storage (in contrast to carbohydrates and proteins, our body has unlimited ability to store fat as adipose tissue)
- Required for nerve transmission
- Fat + cholesterol needed for hormone synthesis (especially testosterone, which can impact the ability to build muscle!)
- Insulation and protection (especially important for athletes who play contact sports)
- Phospholipids are a structural component of cell walls
- Cholesterol is needed to synthesis bile, which is required for digestion
Triglyceride structure
Composed of a glycerol backbone and 3 fatty acids.
Less than 6 carbons = short chain fatty acids
6-12 carbons = medium chain fatty acids
14+carbons = long chain fatty acids
Fat intake recommendation
General population: 20-35% of total energy requirements (less than 10% total energy as saturated fat)
Athletes: 20-35% of total energy requirements (less than 10% total energy as saturated fat). Too low-fat intakes can affect hormones in athletes and should not drop below 20% of total energy.
Role of protein
- Needed for the growth, repair and replacement of these tissues.
- Athlete’s perspective - muscle recovery and repair after activity
- Sructural component of most enzymes, including those which play a role in digesting food (e.g. amylase, lipase, protease) and many hormones (e.g. insulin and glucagon) are also proteins.
- Important role in immune function.
Types of amino acids
Essential (required in the diet),
Conditionally essential (body able to synthesise but still required as part of the diet)
Non‐essential amino acids (the body is able to synthesise these)
Structure of an amino acid
A central carbon atom, bound to hydrogen
An amino group (NH2)
A carboxyl group (COOH)
A side group - the side group varies in complexity and is what makes each amino acid unique.
Protein intake recommendations
Non-athletes: 0.75-1.07 g/kg body weight (NRVs) or 15-25% total energy intake (AMDR)
Athletes: 1.2 -2.0g/kg
Essential amino acids?
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
Conditionally Essential Amino Acids?
Arginine
Cysteine
Glutamine
Histidine
Proline
Tyrosine
Non-essential Amino Acids?
Alanine
Asparagine
Aspartic acid
Glutamic acid
Glycine
Serine
Biological Value?
The proportion of protein which is absorbed by the body from food.
The higher the value, the better quality the protein.
Key micronutrients relating to athletes?
B-Vitamins (for energy),
Calcium and Vitamin D (for bone),
Iron (for blood/energy),
Zinc and Magnesium (for immune function and cell repair),
Potassium & Sodium & Chloride (for fluid balance),
Antioxidant nutrient - Vitamin A, C, E and selenium (for immunity and recovery).
What micronutrients do athletes have increased needs for?
Iron
Sodium
Potassium
+ possibly
B-vitamins
Magnesium
Zinc
