Protein for Sports Performance

According to Class Notes (2015) : 'Proteins are molecules that have many enzymatic and structural functions related to the growth, maintenance and repair.' 

Class Notes (2015) states: 'The goal of dietary protein intake is to contribute the amino acids (EAA’s) necessary to assimilate proteins for skeletal structures and hormones, function as cell membrane receptors and maintain fluid balance.'

Given the definition of what a protein is they are an integral part of any diet. Even more so for a sports performer as proteins primary function is to grow maintain and repair muscle.

Required protein intake is measured by nitrogen balance. For example if the amount of protein intake is positive this is called protein synthesis and if the intake is negative (not enough then this is called protein degradation. 

The video above explains the effects of a positive or negative nitrogen balance. During protein synthesis anabolic processes occur causing muscles to repair and build after exercise. However during protein degradation this is where the muscles have been used during exercise but not repaired by the intake of protein. If you went to the gym and did some strength training but didn't intake protein afterwards the muscles would be damaged and catabolic processes would occur. This shows the importance of protein regardless if your work out or not.

'The RDA (Recommended Daily Allowance for protein in normal sedentary individuals is 0.8g/kgBW (1kg=2.2lbs)' (Class Notes 2015)

However all athletes need an increased amount of protein in their diets compared to sedentary individuals no matter what the sport is. Below is what I researched to show their are different RDA's of protein for contrasting sports performers.

Who? How Much?

RDA for sedentary adult 0.8 g/kg BW/day 
Physically active adult 1.0 g/kg BW/day 
Endurance athlete 1.2 - 1.4 g/kg BW/day 
Strength athlete 1.4 - 1.8 g/kg BW/day 
Adolescent athlete 1.0 - 2.0 g/kg BW/day 
Maximum for adult athletes up to 2.0 g/kg BW/day 

Chowdhury Zaman M.B.B.S., M.S., Dr. Ken Lin, Ph.D. Biochemistry, William O’Neill (2007)


'Protein intake equal to 10-20% of total calories will meet the protein requirements of most athletes. The type of sport and total calorie intakes influence protein requirements. For example, cross country skiing and ice hockey both require a high level of energy intake to meet energy expenditures.' Chowdhury Zaman M.B.B.S., M.S., Dr. Ken Lin, Ph.D. Biochemistry, William O’Neill (2007)

Using the reference theory above I have calculated my protein RDA below:

Sports Performer	Example	Recommended Daily Allowance	My RDA Protein
Sedentary Individual	Exercise less than once a week	0.8 x KgBW	63.2g
Endurance Athlete	Marathon Runner Footballer Basketball player	0.8-1.2 x kgBW	94.8g
Strength Trainer	Power lifter	1.2-1.8 x KgBW	142.2g

If athletes consume 15% of their calories as protein are they getting enough to promote an increase in FFM?

On a day where I complete doerate exercise I require around 3100kcal.

15% of 3100 = 465kcal
465kcal / 4kcal = 116g
116 / 79kg = 1.4g per kg/BW

The idea of consuming 15% of your diet as protein works well as it links in well with the RDA numbers produced earlier. On a moderate exercise day I require 116g of Protein whereas in the study above I varied between 94-142g of protein per day depending on exercise. This number fits in with previous evidence and recommendations therefore it could be a quicker way for an athlete to work out how much protein to intake.

Protein Sources:

Complete Proteins (Contain all 9 essential amino acids EAA's)

Examples: Complete Proteins (Meat, Fish and Diary products)

Incomplete Proteins (Contain some of the 9 essential amino acids)

Examples: (Nuts and Grains)

If an athlete is vegetarian or vegan they can supplement meat and fish with synthesized pure amino acids. They can also use protein shakes to ensure they are receiving all 9 essential amino acids.

Refrences:

Class Notes (2015) Athletic Performance and Protein Intake [Online] Available from: http://vle.chesterfield.ac.uk/course/view.php?id=3196

Christine Dobrowolski (2014) 7.4 Protein: Nitrogen Balance [Online] Available from: https://www.youtube.com/watch?v=9NPGU5XSc54 [Accessed 2015]

Chowdhury Zaman M.B.B.S., M.S., Dr. Ken Lin, Ph.D. Biochemistry, William O’Neill (2007) A Review of the Importance of Amino Acids in Sports Performance [Online] Available from: http://vle.chesterfield.ac.uk/pluginfile.php/283028/mod_resource/content/1/Protein%20%28Amino%20Acids%29%20and%20Sports%20Performance.pdf [Accessed 2015]

Carbohydrates for Sports Performance

The primary purpose for carbohydrates is to provide energy for the brain and muscles. It is also the preferred macronutrient used by the body for energy so it is an important part of a sports performers diet. Carbohydrates are stored within the muscles and liver in the form of glycogen.

Glycemic Index

Carbohydrates can be separated into three groups which are part of the glycemic food index. The first category is the high glycemic index foods and are typical foods such as bagels, white bread and doughnuts. The second category is called moderate glycemic index foods and includes white rice, cereal and pita bread. The final category is called low glycemic index foods and examples of these foods would be beans and milk. 

The reason carbohydrates are split into these categories is because our body reacts differently due to the contents of the nutrient. For instance, this diagram shows a high glycemic food (white bread) and a moderate-low glycemic food's effect on our blood sugar response. Due to high glycemic foods having more glucose in them, our blood sugar levels increase rapidly after eating and then suffer a big drop after an hour. Whereas, a moderate-low glycemic food increases blood sugar levels more evenly over a longer period of time. This is important for a sports performer to understand because different types of carbohydrates will give us different functions. Depending on what sport you are participating in it may be beneficial to consume different types of carbohydrates.

Pre Exercise CHO Requirements

The aim of a pre exercise meal is to maximise the muscle and liver glycogen stores ready to be used during exercise.

A power lifter is performing at a high intensity for a short period of time. More glucose will be expended within a short period of time; therefore it needs to be provided priory to exercise. It would be more beneficial for a power lifter to consume high glycemic foods around 15 minutes before competing. This is because they require a big boost of energy to work at high intensity, high glycemic foods would be perfect for this under an hour. 

Contrasting this sports performer with a marathon runner who is working at a less intensity but require to last longer; because of the lower intensity the carbohydrates need to provide energy for the marathon runner for over 2 hours. Therefore, moderate to low glycemic foods should be apart of the pre exercise meal. The ideal time to eat prior to exercise is 2-4 hours.

Pre Event Nutrition Preparation (2015) states: 'Research suggests that endurance performance is improved when athletes consume a substantial amount of carbohydrate (200–300g) in the 2–4 hours before exercise.'

Therefore, consuming 1-5 grams of Carbohydrate per KG of BW 2-4 hours before exercise would benefit a sports performers performance. If I followed this guideline in my practice I should include between 79-395 grams of CHO in my pre exercise meal.

The video above gives an insight from a professional nutritionist and dietitian on the types and amounts of food that is good to eat before exercise.

Post Exercise CHO Requirements

According to IOC (2015) 1-2 grams of CHO per KG of BW is recommended to be included in your post exercise meal. The meal should be consumed up to 4 hours after completing exercising. Post exercise I should have 79-158 grams of carbohydrate in my meal. 

Refrences:

IOC (2015) Carbohydrate for competition [Online] Available from: http://vle.chesterfield.ac.uk/course/view.php?id=3196 [Acessed 2015]

LIFESTYLE MEDICINE (2013) The Glycemic Index Explained [Online Video] December 2013 Available from: https://www.youtube.com/watch?v=F1YDR2S7SPU [Acessed 2015]

MonkeySee (2013) What to eat before exercise [Online] Available from: https://www.youtube.com/watch?v=ou37Js1mzEU [Accessed 2015]

Class Notes (2015) Carbohydrate for Sport Performance [Online] Available from: http://vle.chesterfield.ac.uk/course/view.php?id=3196

Pre Event Nutrition Preparation (2015) Pre Event Preparation [Online] Available from:  http://vle.chesterfield.ac.uk/pluginfile.php/283037/mod_resource/content/1/Pre-Event%20Nutritional%20Preparation.pdf