Athletes need more proteins than people who remain sedentary. One of the role's that protein plays in tandem with muscles is muscle repair.
Why take proteins?
Muscles are made up of a whole group of tight fibres one against each other. Contractile proteins are present inside the muscle fibres. These proteins have contracting and relaxing properties.
When doing an endurance sport, demands are constantly made of muscles, which provoke micro-lesions that will alter muscle tissue. In response to these micro-lesions, muscles adapt by repairing muscle fibres thanks to amino acids, which are present in proteins.
When should you take proteins?
Depending on your goals, proteins can be taken before and after exercise. Before exercise the spread of amino acids stimulates muscle building and limits muscle destruction during exercise. After exercise the amino acids enable muscle repair of fibres destroyed during exercise.
After exercise, the recovery phase starts. It is characterised with protein biosynthesis restarting. Protein biosynthesis occurs after exercise, and strongly depends on the availability of amino acids, which must be optimal to ensure the repair of proteins destroyed during exercise.
How much protein should I take?
In general, protein needs are covered with a protein intake of between 12 to 14% of overall energy supply.
The endurance athletes protein requirements are between 1.2 and 1.7 g / kg of body weight per day. These values can be varied according to the level of training.
The strength athletes protein requirements are between 1.3 and 1.5 g / kg of body weight per day. In the case of muscle mass development, the requirements must not exceed 2.5 g / kg of body weight, for a period of no longer than 6 months and follow medical advice.
2/3 of intake must be provided by balanced diet intake and the last 1/3 can come from protein supplements.
Just as for endurance athletes, the experimental data available to date for strength athletes remains incomplete and does not demonstrate that consumption of amino acids is a factor leading to improvements in performance. There is no proof that proteins improve performance. However, muscle training and sleep are two important factors in muscle repair. The proteins protect and repair muscle.
How to take proteins?
Protein intake during the day is covered by everyday foods. Taking additional protein with the view to building muscles or for good recovery, can be done by using protein rich powders.
However at least 2/3 of protein intake must be covered by everyday foods, the remainder through supplements but not over 1g / kg of body weight per day in the form high biological value proteins. The carbohydrates and water intake must also be sufficient.
What happens when there is a lack of protein?
A lack of protein is rare when a diet is varied and well-balanced. It can happen when the food intake is low in essential amino acids and especially amongst the elderly, athletes, children during growth, pregnant women or breastfeeding. The signs of deficiency are when their is slowing down of growth, insufficient muscle growth, weight loss, low physical resistance, inadequate resistance to infectious illnesses…
What happens when there is excessive consumption of macronutrients?
An excessive intake of proteins generates excess urea (end product of protein destruction) that needs to be eliminated through urine. It is therefore important for training athletes who take lots of proteins, to ensure they hydrate properly so that there is no urea retention, which is toxic.
In theory, a high protein or amino-acids intake puts the liver and kidney under excessive strain. From a clinical perspective, it doesn't appear that the kidney or liver suffer from excessive protein intake. However, it is well known that a significant protein intake stimulates urinary calcium excretion.
Are proteins used as energy?
The body does possess its own reserves of amino-acids, other than the structural and functional proteins (link to article about protein in the athlete's body). This is why, in the event of a need for energy in the form of amino acids during a long exercise period or in the event of the depletion of carbohydrates and lipid reserves, the destruction of proteins like albumin and haemoglobin in the liver or the muscles help to ensure the supply of amino acids. Given their quantitative importance to the body, muscles represent the biggest potential reservoir in amino acids.
Are proteins natural?
Proteins are natural and can come from several sources:
- dairy products…
Are proteins dangerous?
The recommended nutritional requirements in proteins indicates the intake required to cover the needs of different parts of the population. By respecting this intake, proteins are of no risk to the body.
However, an excess in proteins is not without its consequences, and must be done in association with a heath status check-up. As a matter of fact an excessive intake cannot be justified in terms of effectiveness and risks being a health hazard by increasing urinary excretion of nitrogen and calcium.