Introduction to Sports Nutrition

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Top Contributors - Wanda van Niekerk, Jess Bell and Lucinda hampton  

Basics of Nutrition

Macronutrients

Macronutrients provide calories or energy to the body. Their function is to promote:

• cellular growth
• metabolism
• maintenance of normal bodily functions

Macronutrients are necessary in large amounts to provide a full and proper effect. The three types of macronutrients are:

• carbohydrates
• proteins
• fats

Carbohydrates	Proteins	Fats
Body's main fuel source Broken down into blood glucose Red blood cells and the brain only use glucose for energy Types: sugars, starch, fibre	Chemical foundation for all cells, antibodies, enzymes and hormones Amino acids are the building blocks of proteins Promotes wound healing Plays a role in development and repair of bone, muscle and skin Protein needs are increased during more stressful times and/or during illness Essential for transport of oxygen around the body	An essential nutrient, necessary for normal functioning of the body Concentrated form of energy Help maintain body temperature and insulation of body organs Necessary for health skin and normal nerve function Carry the fat-soluble vitamins A, D, E, and K

Micronutrients

Micronutrients are essential, but we need these in smaller amounts. Micronutrients are necessary for cell growth and function. The human body can not produce micronutrients so it must be consumed.

Vitamins	Minerals
Fat soluble - absorb through intestines with fat (Vit A, D, E, K) Water soluble - dissolve in water (Vit B complex and C)	Fluid and electrolyte balance (sodium, potassium) Bone health (calcium, magnesium) Oxygenation of blood (iron)

Water

• Humans are 2/3 water
• Water is best for hydration, but any calorie-free, non-caffeinated, non-alcoholic fluid can work
  • Caffeine and alcohol function as diuretics

Food Groups

• Fruits
• Vegetables
• Protein
  • Plant based sources
    • beans, lentils, legumes
    • nuts, nut butter, seed
  • Animal based sources
    • Poultry
    • Lean cuts of beef and pork
    • Oily fish
• Grains/starch
  • Whole grains
    • Quinoa, oats, barley
  • Popcorn
  • Potatoes, corn, peas(nutritional make up of these are more similar to grains than vegetables)
• Dairy
  • Milk, yoghurt, cheese
  • Non-dairy milks and yoghurt
  • Kefir
• Fats
  • Plant based fats are better
    • Avocado, olives, nuts/seeds

Link to Choose My Plate

Portion Size

Quantity	Estimated Portion Size	Food
3 Poultry or meat	Size of a smart phone (3 -d configuration)/ deck of cards	Chicken, steak
1 cup	Size of a baseball	Uncooked fruit and vegetables
1/2 cup	Size of a light bulb	Cooked fruit and vegetables, grains
1 ounce or 2 tablespoons	Size of a golf ball	Peanut butter, salad dressing, hummus
1 Tablespoon	Size of a poker chip	Olive oil
1 1/2 oz cheese	Size of a lipstick tube	Cheese

Hunger/ Fullness Scale

0	Starving, weak with hunger, may not feel anything but headache, irritability, lightheadedness
1	Very hungry/famished - too hungry and will eat anything and/or want to eat anything
2	Preoccupied with hunger - stronger physical signals
3	Hungry and the urge to eat food is strong, body sending signals to eat - stomach growling
4	Starting to get hungry, can wait for desire to develop fully, or have a snack
5	Not hungry, not full - neutral (in between meals/snacks)
6	Starting to eat, need to keep eating
7	Eating, enjoying food, but not yet satisfied, close to finishing
8	Satisfied, comfortable full, good time to stop eating
9	Quite full, some discomfort, a few bites past satisfaction, food seems less delicious
10	Uncomfortable, painfully full

• Helpful tool to use
• Start eating at around 3, generally
• Stop eating at around 8, generally
• Ebb and flow between 3 and 8 on the scale

Sports Nutrition

Energy Balance and Exercise

All info from: Chapter 5: Energy Requirements and Measurement of Energy Expenditure

• Energy balance is important for athletes wanting to change their body mass and/or body composition in order to improve performance or make a specified weight category for their sport.
• Insufficient energy consumption in relation to expended energy will result in the effects of training being lost, as muscle and fat will be used as energy sources
• Restricted energy intake may compromise and athlete's ability to obtain necessary nutrients
• Athletes need to consume enough energy to cover the energy costs of:
  • daily living
  • their sport
  • building and repairing muscle tissue
• Energy balance = Ein = Eout
  • Ein = energy consumed
  • Eout = expended energy
• Energy balance is a dynamic process
  • for example, if energy intake is changed through a different diet, this can affect the physiological and biological components of energy expenditure
• Influencing factors of energy balance can be:
  • internal
    • genetic
    • epigenetic
    • metabolic
    • hormonal
    • neural
  • external
    • environmental
    • social
    • behavioural

Table Influencing factors on energy intake and expenditure

Energy intake	Energy expenditure
diet composition timing of intake exercise intensity types of food	diet composition exercise intensity sedentary behaviour resting metabolic rate

Training Consequences of a Negative Energy Balance

find references

• Increased risk of stress fractures
• Decreased athletic performance
• Slower phospocreatine recovery rates
• Athlete enters a hypometabolic catabolic state (low insulin growth factors, high cortisol-releasing hormone, high cortisol levels) and this hinders the addition of lean muscle mass
  • Increased risk of injury
  • Decreased metabolic rate
  • Breakdown of lean tissue

How Many Calories do Athletes Need?

• TEE = REE x AL x TAE (ref)
  • TEE = Total energy expenditure
  • REE = Resting energy expenditure
  • AL = Active lifestyle
  • TAE = Training activity energy

• Adequate calories are a vital component of nutrition for athletes
• Quality is just as important as quantity (what you eat is just as important as how much you eat) (YOUTUBE VIDEO REFERENCE)

Carbohydrate Intake and Needs for Athletes

Carbohydrates for athletes:

• Provide energy
• Contributes:
  • dietary fibre
  • Vitamins for example vitamin B complex
  • Antioxidants in fruits and vegetables

Considerations when discussing carbohydrates with athletes:

• quality of carbohydrates (low versus high quality)
• High versus low glycaemic index
• Timing of intake
• Variety of sources necessary
  • vegetables, fruits, sweet potatoes, quinoa, brown rice, wild rice, nuts, seeds

Resources

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