You may have heard of protein, but do you know what it is, what it does and the best sources?
What is Protein?
Protein, along with carbohydrates and fats are macronutrients, these are nutrients that the body requires in large amounts to produce energy. In addition to being essential sources of energy, macronutrients carry out a variety of functions in the body. During digestion, proteins are broken down into smaller units, called amino acids. Amino acids are the fundamental building blocks of life, and they form the structure of our organs. They can be found in every cell in our bodies and are essential for growth, development, and repair. Apart from water, protein is the most abundant compound found in the body with around 45% of it being stored in the muscles. Protein is also very important for bone and muscle health, this becomes especially important as we age when muscle mass and bone density naturally decrease.
Protein in the diet
So, we have established that protein is essential for our body, but it is also important to know what foods provide us with protein. As we previously mentioned, protein is made up of a combination of amino acids. In total, there are approximately 20 different amino acids that the body requires for different roles in the body. The body can make 12 of these, however, 8 of them can only be provided throughout our diet. Many different foods provide us with protein with rich sources coming from meat and fish. These animal sources of protein are called ‘complete’ sources as they contain all 20 amino acids.
Plant-based foods such as beans and vegetables are also good sources of protein, however, they do not contain all 20 amino acids and are, therefore, called ‘incomplete’ proteins. To ensure we get all the amino acids the body requires, it is recommended to eat a variety of foods, this will ensure all 20 amino acids are available. The key here is to eat as many different plants as possible, these will also be a great source of fibre. Some examples of good sources of plant-based proteins that you could include in your diet can be found through this link.
Protein and Appetite
Eating protein throughout the day with each meal is also recommended. The body can only digest and utilise a certain amount of protein at one time, therefore ensuring that protein-rich foods are consumed over the day will allow the body time to absorb the nutrients effectively. Consuming protein with each meal could also have a positive effect on your appetite. As protein is a complex structure, it takes longer to digest than fats and carbohydrates, and therefore takes longer to pass through the digestive system. The positive effect of this is that it makes you feel fuller for longer and more satisfied. This is great news for people who are looking to lose weight or reduce their snacking between meals.
The body must receive adequate amounts of protein from the diet to prevent illness, and it is recommended that adults consume 0.75g of protein per kg of body weight. For an average size woman, this equates to around 45g of protein and around 55g for a man. To reach these requirements, a healthy balanced diet is recommended. A list of dietary sources of protein can be found here.
In recent years, food manufacturers have released several products including milkshakes, cereals and even chocolate bars that have a higher protein content, and these products often come with an inflated price tag. Although these products can be beneficial for some people to meet their protein requirements, the average protein intake for both men and women in the UK exceeds the requirements.
The Take-Home Message
Protein is a macronutrient that provides the body with energy. In addition to providing energy, protein is used for many biological processes and is found in every cell and tissue in the body. Proteins are broken down during the digestion process into smaller units called amino acids. There are around 20 amino acids that the body requires. Only 12 of these amino acids can be made by the body, therefore 8 amino acids must be provided through a varied diet. The optimum protein intake is 0.75g per kg of body weight. This requirement can be achieved through a healthy balanced diet and incorporating a wide variety of foods will improve overall dietary intake.