getpro in the gym

What is protein

Along with carbohydrates and fats, protein is a macronutrient that our bodies need in larger quantities to provide us with energy and support a number of important functions1. But just what does protein do for the body? Here we’re exploring the roles of protein in the diet, different sources of protein, and how much of it you need.

Amino acids - the building blocks of protein

Proteins are formed of long chains of amino acids, also known as the ‘building blocks of protein’. When we consume proteins in the foods we eat, the body breaks them down into amino acids which it then to make the proteins it needs2,3

There are twenty amino acids in the body, but only nine of these are considered ‘essential’. That’s because our bodies cannot make them on its own, so we need to get them from our diet2,3

Why is protein important?

Whether you’re a seasoned gym goer or otherwise, your body needs enough protein. Getting the right amount of protein is important not only for our overall health, but it also plays a role in muscle recovery and growth after exercise8.

The body contains thousands of different proteins, and they all have a role to play. Some of the functions of protein in the body include:3, 5, 7, 9:

  • The growth and repair of body tissues

  • The activity and production of enzymes

  • The immune response 

  • Transporting nutrients

In addition to the above, proteins are needed to form key structures in the body such as our muscles and bones. They also play a key role in the immune response and transporting key nutrients, for example, the protein haemoglobin (found in your red blood cells) helps to deliver oxygen throughout the body2,11

GetPRO Caramel Protein

Sources of protein in the diet

Luckily, there’s a wide variety of animal and plant-based sources of protein to choose from, making it that little bit easier to meet your daily protein needs. 

Good sources of animal-based protein include3

  • Lean meat and poultry

  • Fish and seafood 

  • Dairy products - such as milk, cheese and yoghurts

  • Eggs

If you’re following a plant-based diet, sources of protein include10

  • Soya plant-based alternatives to dairy (for examples soya yoghurts and drinks)

  • Legumes and pulses 

  • Nuts and seeds 

  • Tofu and other meat substitutes

With the exception of soya, most plant foods do not provide all of the essential amino acids3. So, if you don’t consume animal sources of protein, it’s a good idea to eat a variety of plant-based protein sources across the day to ensure you meet your full amino acid needs.

If you’re wondering just how much protein you need, you can find out more about your recommended protein intake here.

GetPRO Caramel Protein


Here in the UK, most adults are likely to get enough protein from their diet3. Some people may choose to use protein supplements because they can be a convenient way to increase your protein intake - especially if your goal is to build muscle. However, we would always recommend a food-first approach when it comes to nutrition. That’s because most people can get all the protein they need from eating a variety of protein sources, as part of a healthy balanced diet.

So, what are the different types of protein supplements? Let’s take a look. 

Whey and casein are the two main proteins present in milk. Out of all the animal-based proteins, milk protein contains the highest amount of leucine, an essential amino acid which is important for protein synthesis (aka the process of muscle growth)8

  • Whey protein is absorbed faster making it a top choice for gym-goers after a workout13. It can be a quick and easy way to add more protein to smoothies, shakes and other recipes.

  • Casein protein is absorbed more slowly than whey and may support overnight recovery from exercise12,13. This makes it a popular choice before bed.

If you’re considering taking a protein supplement, it’s important to always follow the dosage guidelines and speak to a healthcare professional before doing so, to ensure that this is the right thing for you. This is particularly important for athletes who compete at high level.

Read more

  1. World Health Organization. Macronutrients [online] 2023. Available at,be%20divided%20into%20three%20groups. [Accessed November 2023]
  2. Lopez, M. J., & Mohiuddin, S. S. (2020). Biochemistry, essential amino acids. Available at: [Accessed November 2023]
  3. British Nutrition Foundation. Protein [online]. Available at [Accessed November 2023]
  4. NHS. Meat in your diet. 2021.   Available at [Accessed November 2023]
  5. Wolfe RR, Cifelli AM, Kostas G, Kim IY. Optimizing Protein Intake in Adults: Interpretation and Application of the Recommended Dietary Allowance Compared with the Acceptable Macronutrient Distribution Range. Adv Nutr. 2017 Mar 15;8(2):266-275. doi: 10.3945/an.116.013821. PMID: 28298271; PMCID: PMC5347101.
  6. Lopez MJ, Mohiuddin SS. Biochemistry, Essential Amino Acids. [Updated 2023 Mar 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:
  7. Cuanalo-Contreras, K., Mukherjee, A., & Soto, C. Role of protein misfolding and proteostasis deficiency in protein misfolding diseases and aging. International journal of cell biology, Published 2013.
  8. Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20. Published 2017 Jun 20. doi:10.1186/s12970-017-0177-8
  9. LaPelusa A, Kaushik R. Physiology, Proteins. [Updated 2022 Nov 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:
  10. NHS. The vegan diet [online] 2022. Available at [Accessed November 2023]
  11. Thomas, C., & Lumb, A. B. (2012). Physiology of haemoglobin. Continuing Education in Anaesthesia, Critical Care & Pain, 12(5), 251-256.
  12. Res PT, Groen B, Pennings B, Beelen M, Wallis GA, Gijsen AP, Senden JM, VAN Loon LJ. Protein ingestion before sleep improves postexercise overnight recovery. Med Sci Sports Exerc. 2012 Aug;44(8):1560-9. doi: 10.1249/MSS.0b013e31824cc363. PMID: 22330017.
  13. Kerksick CM, Arent S, Schoenfeld BJ, et al. International society of sports nutrition position stand: nutrient timing. J Int Soc Sports Nutr. 2017;14:33. Published 2017 Aug 29. doi:10.1186/s12970-017-0189-4
  14. COMA. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom – Report of the Committee on Medical Aspects of Food Policy. Published 1991. London: TSO
  15. Graf S, Egert S, Heer M. Effects of whey protein supplements on metabolism: evidence from human intervention studies. Curr Opin Clin Nutr Metab Care. 2011 Nov;14(6):569-80. doi: 10.1097/MCO.0b013e32834b89da. PMID: 21912246.