What does protein do?
A firm, powerful body with good muscle definition is the aim of all strength trainers. There are many forms of strength training and they are all effective in building muscle, but only with the correct nutrition. Protein is essential for muscle building and repair. It is also vital for healthy bones, cartilage, skin and blood as well as the development of enzymes, hormones and vitamins in the body.
When you exercise, muscle fibers are placed under stress and this causes micro tears. That’s why muscles can ache a day or two after an exercise session. The body immediately sets out to repair the damage using nutrients including amino acids, which are made available by the metabolism of protein. The muscle proteins created are myosin and actin and during the repair process these build up in the fibers to create stronger muscles.
The importance of protein in this process is evident and it might seem reasonable to assume that eating more protein will result in more effective muscle development. However, this is not true and later in this article we will look at the reasons why.
So how much protein is the right amount?
Adults who undertake limited exercise are advised to consume 0.8 grams of protein for each kilogram of bodyweight. For an adult weighing 80 kilograms (176 lbs) this would work out at 64 grams (2.3 oz) of protein daily. For higher levels of activity, the daily protein requirement increases. In the case of a strength trainer, to ensure good muscle growth the protein requirement effectively doubles to 1.6 grams of protein for each kilogram of bodyweight. So for an 80 kilogram (176 lbs) adult the amount would be 128 grams (4.5 oz) of protein a day.
Aerobic exercise is even more demanding of protein, due to the body’s need for additional energy. Although the body uses carbohydrates for energy first, when supplies from this source are exhausted, it will utilize components from certain proteins to supply additional energy. The components it uses are called branched-chain amino acids (BCAA). To allow for aerobic sessions the recommended protein requirement increases to some 1.8 grams per kilogram which equates to a total of 144 grams (5.1 oz) for our subject weighing 80 kilograms (176 lbs).
In preparation for competition, bodybuilders decrease their calorie consumption to reduce body fat levels. At this stage it is important to maintain a high protein intake to avoid loss of muscle along with the fat. So pre-competition, protein levels should be within the range of 1.8 grams to 2.0 grams per kilogram of bodyweight or 144 grams (5.1 oz) to 160 grams (5.6 oz) for a 80 kilogram (176 lb) person.
Protein is vital in building and maintaining good muscularity. Although athletes and strength trainers must consume more protein than those who take little or no exercise, there is no benefit in exceeding the guidelines above.
Good Sources of Protein
There is a wide range of protein rich foods suitable for meat eaters and also vegetarians. For meat eaters, chicken, turkey, fish are excellent, low fat choices. However, red meat is also a rich source and although it does contain a higher proportion of fat than its paler counterparts it also delivers high levels of zinc and iron, both essential for good health. Other meats such as pork and lamb are also generally higher in fat than poultry and fish but if lean cuts are selected, then these are also excellent protein options. Also supplements such as milk and egg protein powder are great when you are on the run.
It is important to remember that not all of the daily protein requirement should be derived from animal sources. There is a vast array of protein rich options suitable for non-meat eaters including beans, nuts, eggs, tofu and dairy products like low-fat and non-fat cheese, milk and yogurt. However vegans, who do not eat any animal products like eggs or dairy products, face a challenge in ensuring that all of the essential amino acids are included within their diet.
There are 20 amino acids and of these, nine are classed as “essential” which means they can only be obtained from food. The remaining 11 “non-essential” amino acids can be produced by the body from other compounds. Foods that contain all of the essential amino acids are known as “complete” proteins and these are almost exclusively from animal sources including meat, dairy products and eggs.
Soyabeans are the main exception to this rule and offer one of the few complete protein sources to those following a vegan diet. To ensure an adequate supply of amino acids, vegans are advised to eat a slightly higher amount of protein (approximately 10% more) each day than non-vegans and to include a wide variety of beans and grains in their diet.
The dangers of a high protein diet
It is clear that protein plays a vital role in building and maintaining muscle. Many well publicized diets advocate a high protein regimen for effective weight loss and many, including high profile celebrities, have testified that they do really work. So it appears logical to assume that eating a larger amount of protein than the recommended amount could boost muscle development and assist with faster weight loss.
But surprisingly this is not the case.
High protein diets are in fact detrimental to the body for a number of reasons. Firstly, they are usually very low in roughage which slows down digestive transit and causes constipation which contributes to a feeling of general sluggishness. A second problem is that the high protein diet often comprises a high proportion of meat and dairy products which are loaded with saturated fats and cholesterol, both of which have serious implications for overall health and cardiac health in particular. Thirdly, when excess protein is present in the system, it is broken down by the body with some being converted into urea which is then excreted in the urine. A large amount of nitrogen is created by this metabolic process which is passed through the kidneys, causing stress to these organs and can lead to long term health problems.
Furthermore, any remaining protein will be converted into glucose and if the body does not need the glucose immediately it will be stored as body fat. Finally, the presence of high protein levels causes calcium depletion and this can be problematic in later life, with women in particular being vulnerable to brittle bones (osteoporosis).
So given these adverse effects, there is clearly no benefit in eating more protein than the body needs. Following the daily guidelines for your bodyweight, sex, age and level of activity will ensure that you get the optimal amount for your personal requirements to build and maintain muscle strength.