What is protein?

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Everything you thought you knew but didn’t

Most of us know what protein is. Along with carbohydrates and fats, it makes up the three most important macronutrients of our diet.  Research has shown why it’s so beneficial as part of a balanced and healthy diet, as it plays a key role in the creation and maintenance of every single cell in our bodies.¹ So what happens if we don’t get enough protein and what are the best food sources to ensure we get the right amount?

Why our bodies need protein

Did you know that there are over 10,000 types of protein in everything from our internal organs to our tissues, muscles, skin, hair and bones? Every single cell in our body contains protein, and protein is needed in our diets to help those cells repair and regenerate.² Protein is critical in aiding the processes that give us energy and help move oxygen around in our blood. It is absolute essential for keeping us healthy and ensuring our bodies continue to work as they should do:

Building cells

Bones, muscles, cartilage and skin can only be built with the help of protein.  

Repairing tissue

Protein is needed to build and repair damaged tissue.

Oxygenating blood

The protein compound in red blood cells delivers oxygen throughout the body and supplies it with the nutrients we need.

Aiding digestion

Dietary protein makes enzymes, which help us to digest food properly, and make new cells and body chemicals.

Regulating hormones

Protein helps to keep our hormones regulated, which is particularly important when cells are developing and transforming during puberty.

…and there are even more benefits to eating protein!

Protein is often at the forefront of those trying to either lose weight or build muscle and that’s because it’s great for doing both! Studies have shown that not only does protein reduce cravings and desires for late night snacking,³ but protein is the most satiating of the macronutrients and will curb your appetite longer than carbohydrates and fats.⁴ Numerous studies have also shown that you can increase strength and muscle mass, as well as decrease muscle loss,⁵ by eating plenty of protein.

Essential amino acids

During digestion, the protein we consume is broken down into amino acids – it’s these amino acids that are the building blocks of protein. The British Nutrition Foundation recognises around 20 different amino acids, of which 9 are needed in an adult diet to maintain good health.⁶ These are known as Essential amino acids and can only be made through eating protein-rich foods.

How much protein do we need and what foods are the highest in protein?

Whilst it will depend on your age and weight, research has shown that adults need on average around 0.6g of protein per kilogram of bodyweight each day. Infants, children, pregnant and breastfeeding women have different requirements.⁷

Protein can be found in high amounts in meats, milk, fish, and eggs. If you are vegetarian or vegan you don’t need to worry though as you don’t need to eat animal products to get the protein you need. You can also find it in soy, beans, legumes, nut butters, and some grains (wheat germ and quinoa, for example).

What are the different types of protein?

Protein falls into different types, which is another bonus for people who have to, or choose, to avoid certain food groups.

Casein protein is found in milk, but is absorbed and digested much more slowly, so it may be a suitable option if you are lactose intolerant.

Egg protein is a great option for those who need to avoid dairy but are still looking for an animal-based protein source. Of all whole foods, eggs have been shown in studies to contain the greatest protein digestibility-corrected amino acids.⁸

Pea protein is great for people with allergies or sensitivities to eggs or dairy, and for those following a vegetarian or vegan lifestyle.

Hemp protein is an easily-digested source of plant-based protein that is rich in several amino acids – although it only has low levels of the amino acids lysine and leucine.

Brown rice protein contains all the essential amino acids but is not considered a complete protein as it is too low in lysine. 

Mixed plant proteins can be a great option for those looking to avoid meat-based products but wanting to get high amounts of all the amino acids. Protein powders commonly blend plant sources so there are different options to suit your tastes and needs.

Whey protein and exercise

Whey protein is one of the most popular types of protein, especially when it comes to being used for sporting or fitness performance. Whey protein comes from milk and is the liquid that separates from the curds during the cheesemaking process. It’s a high source of protein that studies have shown can lead to the largest decrease in appetite for those trying to manage their weight.⁹

Whey protein has been shown in studies to improve exercise performance, as well as help to improve body composition through increasing muscle weight. In addition, it has shown to increase physical endurance and also slightly increase physical strength.¹⁰

Not all protein is created equal

When it comes to protein supplements, such as protein powders, the quality can vary. Not all whey proteins are the same, and not all of them will provide the same benefits. The key thing to look for is whether the protein has been denatured. When this happens, it’s the biochemical process in which proteins lose their structure, and it no longer performs its functions as well. When it comes to denatured protein powder, it means that the structure of the amino acids has been broken down by the exposure of whey protein to acids, oxidation of the amino acids or high heat during the pasteurisation process.

Due to this, it’s always better to look for non-denatured, or undernatured protein, as that will provide the most benefits by avoiding the breakdown of the vital immune-boosting proteins that make whey so beneficial. The best non denatured whey proteins are made with minimal processing and a cold filtration process.

Protein and your diet

While protein is extremely important, it’s not something you need to be overwhelmed by. You don’t need to consume your full daily recommended amount of protein in one sitting, as it’s more important to balance it over the course of the day.

Whatever your dietary preferences or health goals, there are plenty of protein-rich foods to keep you in top health while letting you enjoy and delight in what you eat.

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2. Protein in diet: MedlinePlus Medical Encyclopedia [↩]
3. The effects of consuming frequent, higher protein meals on appetite [↩]
4. The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review [↩]
5. Increased protein intake reduces lean body mass loss during weight loss in athletes [↩]
6. Protein – British Nutrition Foundation [↩]
7. Protein – British Nutrition Foundation [↩]
8. The protein digestibility-corrected amino acid score – PubMed [↩]
9. The acute effects of four protein meals on insulin, glucose, appetite and energy intake in lean men [↩]
10. Whey Protein Improves Exercise Performance and Biochemical Profiles in Trained Mice [↩]