Nutrition for Sports Performance

Importance of nutrition

· Good nutrition is essential to:

– Preserve and build muscle

– Maintain healthy bones

– Maximize oxygen transport and use

– Repair existing cells and create new tissue

– Maintain optimal fluid and electrolyte balance

– Provide energy

Benefits

· Optimal gains from the training programme

· Enhanced recovery between workouts and events

· Achievement and maintenance of an ideal body weight and physique

· A reduced risk of injury and illness

· Confidence in being well-prepared to face competition

· Consistency in achieving high level competition performances

Macro & Micro Nutrients

Macros

· Carbohydrates – Provide energy to fuel performance.

· Protein – Repair tissue damage following performance.

· Fats – Secondary fuel source and helps the absorption of essential vitamins and minerals.

Micros

· Vitamins – organic compounds responsible for normal bodily functions.

· Minerals – Inorganic compounds responsible for normal bodily functions.

· Water – Essential for the transportation of nutrients around the body, cellular function, body temperature & removal of waste products

Carbohydrate Requirements:

· Stored as glycogen in the muscles

· Preferred/ Major source of energy

· Broken down rapidly

· Important in maximal exercise

Carbohydrates also:

· Power muscle contraction

· Provide fuel for the brain

· Aids in fat metabolism

· Protein sparing effect: Allows protein to be used for tissue maintenance/repair versus energy

· RDI = 6-10 g/kg BW per day

Glycaemic Index

The glycaemic index (GI) is a ranking of carbohydrates on a scale from 0 to 100 according to the extent to which they raise blood sugar levels after eating. Foods with a high GI are those which are rapidly digested and absorbed and result in marked fluctuations in blood sugar levels.

Low vs High GI CHO’s

Compared to ingesting simple carbohydrates, ingesting complex carbohydrates:

· Increases muscle glycogen stores better

· Improves performance and delays fatigue

· Promotes faster stomach emptying

· Causes less stomach upset and indigestion

· Leads to lower blood sugar and insulin levels

· Provides other beneficial nutrients (fibre, vitamins and minerals)

Protein Requirements

Role in the body:

· Tissue maintenance

· Tissue repair

· Tissue growth

· Energy source (to a lesser degree)

· RDI = 1.6-1.8 g/kg BW per day

Amino Acids

· Amino acids are organic compounds that combine to form proteins.

· Amino acids and proteins are the building blocks of life.

· When proteins are digested or broken down, amino acids are left.

· The human body uses amino acids to make proteins to help the body: Break down food, Grow, Repair body tissue & perform many other bodily functions.

· Amino acids can also be used as a source of energy by the body.

Essential amino acids

· Essential amino acids cannot be made by the body. As a result, they must come from food.

Non-essential amino acids

· "Non-essential" means that the body produce an amino acid, even if we don't get it from the food we eat.

Fat Requirements

Fat is an essential part of your diet. It provides energy, absorbs certain nutrients and maintains your core body temperature.

• Release energy. Several B vitamins are key components of certain coenzymes (molecules that aid enzymes) that help release energy from food.

• Produce energy. Thiamin, riboflavin, niacin, pantothenic acid, and biotin engage in energy production.

• Build proteins and cells. Vitamins B6, B12, and folic acid metabolize amino acids (the building blocks of proteins) and help cells multiply.

• Make collagen. One of many roles played by vitamin C is to help make collagen, which knits together wounds, supports blood vessel walls, and forms a base for teeth and bones.

• Build bones. Bone formation would be impossible without vitamins A, D, and K.

• Protect vision. Vitamin A also helps keep cells healthy and protects your vision.

• Interact favorably. Without vitamin E, your body would have difficulty absorbing and storing vitamin A.

• Protect the body. Vitamin E also acts as an antioxidant (a compound that helps protect the body against damage from unstable molecules).

Minerals

• One of the key tasks of major minerals is to maintain the proper balance of water in the body. Sodium, chloride, and potassium take the lead in doing this.

• Another key function of minerals is to ensure normal bodily functions and optimising immune function.

Hydration Strategies

• Maintaining fluid balance, or hydration, is an important factor in preserving various body functions and supporting exercise performance.

• The most practical way for athletes to monitor their sweat loss is to measure changes in body mass 1kg weight loss = 1litre of fluid loss.

• Ensure adequate hydration prior to and during competition to minimise the risk of dehydration as exercise performance is impaired when an athlete is dehydrated by as little as 2% of body weight. Losses in excess of 5% of body weight can decrease the capacity for work by about 30%.

Pre-Competition Nutrition

• Consume a high – Low GI CHO and protein meal 3-4 hours prior to competition (1.5-2g. kg/bw).

• Consume a high GI snack 15-20 mins before and during competition (bars, gels, isotonic drinks).

• Consume approx. 500ml of water per hour for 4 hours before competition – added electrolytes for salty sweaters.

Post Competition Nutrition

• Consume a high GI and protein recovery shake within 30 mins of competition.

• Replace fluid loss with added electrolytes within 4 hours (pre & post weight).

• Consume an anti-oxidant immediately after competition (cherry active)

• Consume a large high GI (1.5g / kg.bw) and protein meal within 2 hours of competition.

• Continue to replenish on CHO and protein every 3-4 hours for 24 hours post competition.

Carbo Loading

• Increases the body’s pre-exercise glycogen stores by 50 to 100%

• Benefits endurance athletes who compete for longer than 90 minutes

– Can increase endurance up to 20%

– Can increase performance by 2 to 3%

Days prior to event Exercise duration Carbohydrate intake:

6- 90 minutes 5 gm/kg/day

5- 40 minutes 5 gm/kg/day

4- 40 minutes 5 gm/kg/day

3- 20 minutes 10 gm/kg/day

2- 20 minutes 10 gm/kg/day

1- rest 10 gm/kg/day