Supplements

What Does Protein Do To Your Body?

Introduction

Protein is often spoken about as being the building blocks of life - but what does protein do to your body? What happens when you eat enough protein, compared to when you don’t eat enough? Whether you’re an athlete, a weekend gym warrior, simply trying to stay healthy or anywhere in between, understanding the role protein plays in your body is crucial.

There’s a lot of hype, myths & uneducated claims about protein circulating online - from people claiming you need huge amounts to build muscle, to others suggesting it damages your kidneys. This guide cuts through the noise with straightforward facts that anyone can understand, so you can feel confident about how much protein you need and why it matters.

What Are The Benefits of Protein?

i) Protein’s Role in Muscle Growth & Repair

Whenever protein is mentioned, the first thing that comes to mind for most people is muscle. After you consume protein, your body breaks it down into amino acids, the molecules that rebuild/ build muscle tissue, produce enzymes & support countless cellular processes.

This process is called muscle protein synthesis, and is the main driver of muscle growth & repair after training. It’s no real surprise that if you want to build muscle, get stronger, or recover more quickly, consuming adequate protein is an obvious choice.

Breaking it down further, Branched-Chain Amino Acids (BCAAs) which are the basic building blocks of protein themselves have been shown to offer beneficial effects for decreasing exercise-induced muscle damage and promoting muscle-protein synthesis (the muscle building process) (1) - a diet rich in protein is also a diet rich in BCAAs.

This 2012 review (2) & this 2010 review (3) that looked at the effect that protein has on muscle growth, further demonstrates the role that protein plays in maximising muscle protein synthesis, which more or less drives hypertrophy/ muscle growth.

So basically, eat adequate protein to support muscle growth. But, does when you consume it actually matter?

This 2013 study (4) on nutrient timing suggested that the larger the protein serving in your meals, the further apart your protein servings can be consumed. However, consuming adequate protein consistently throughout the day is far more important than immediately ingesting some within, say, 30 minutes of finishing a workout.

Optimum Nutrition’s Gold Standard 100% Whey is thebest-selling protein powder world-wide. It contains 24 grams of protein & 5.5 grams of BCAAs per serve, and as it is comprised primarily of whey protein isolate (the highest quality protein source available), it mixes easily & is absorbed quickly.

ii) Protein’s Role in Metabolism & Weight Management

Protein isn’t just for muscle, however higher protein diets also assist with preserving more of it when losing weight. It also plays a key role in boosting your metabolism, appetite control & managing your weight.

The Thermic Effect of Food (TEF) - digesting & processing protein burns more calories compared to fats or carbs. This 2004 study (5) actually found that protein increases the thermic effect of food by up to 20-30% when compared to carbs and fats.

Because of this, following a higher protein diet versus a lower protein diet (where total calories are matched between the two diets) can further help with weight loss goals through a greater TEF (6).

This 2009 study (7) on weight loss further supports the idea that by following a higher protein diet, you can see favourable outcomes on weight management, weight loss & hence improved body composition.

They also discuss how higher protein diets can help with the sensation of feeling fuller for longer, which in turn can have a positive effect on reducing cravings & hence further support weight loss.

iii) Protein’s Role in Immune Health & Overall Wellbeing

Protein is also essential for enzymes, hormones, neurotransmitters & the immune system within the body.

This 2013 study (8) on the immune system discusses how practically all forms of immunity are affected by a lack of protein in the diet

This 2025 review (9) also suggests that protein can assist with optimising immune function & the recovery process from injury in sports, which further ties in with its impact on building muscle & repairing those tissues & structures.

This 2013 review (10) on protein intake in older individuals also reinforces just how important protein is amongst all age groups, demonstrating that older adults specifically are more in need of protein to support good health, promote recovery from illness & maintain functionality.

How Much Protein Does Your Body Need?

Protein needs tend to vary depending on your goals, age & activity levels, as well as how much muscle mass you have.

Generally speaking, the more muscle mass you have, the more activity & exercise you do, the more protein you’re going to require. There’s also an argument for increased protein intakes in older populations, and for the purposes of recovery from illness or injury.

Here are some general guidelines based on activity levels:

Sedentary adults: ~0.8g protein per kg of bodyweight
Active individuals: 1.2-1.6g protein per kg of bodyweight
Strength athletes: 1.6-2.2g protein per kg of bodyweight
Older adults: 1-1.2g protein per kg of bodyweight

If you’re not sure of which category you fit into, there’s a much easier way to determine how much protein you should be eating each day.

CLICK HERE to access the Optimum Nutrition Protein Calculator and have your protein needs calculated based on your individual goals.

Protein Myths

1) ‘You should consume protein within 30 minutes of finishing a workout’

This is a myth. This 2013 study (11) on nutrient timing suggested that the larger the protein serving in your meals, the further apart they can be consumed & that consistently consuming adequate protein throughout the day is far more important than immediately ingesting some within 30 minutes of finishing a workout.

2) ‘You can only absorb 30g of protein in a single serve, so more than one scoop of protein powder is unnecessary.

This is a myth. Studies like this 2023 (12) study on the anabolic response to protein during recovery shows that as the amount of protein consumed per meal increases, so too does the anabolic (muscle building) effect of that meal. Hence you should worry less about how much protein you consume per serve, and more on how much you consume over the course of the day.

3) ‘High protein diets damage your kidneys’

This is a myth. For individuals with healthy kidney function, moderate protein intake is generally considered safe. *Always consult a healthcare professional or registered dietitian before significantly increasing protein intake particularly if you have concerns about kidney health. This 2025 review (13)on protein intake & renal function found no significant evidence for any detrimental effect of a higher protein intake on kidney function.

FAQ: Protein & Your Body

Q: What happens if I don’t eat enough protein?

A: You can risk muscle loss, impaired recovery, weakened immunity, and even a slower metabolism.

Q: Why is protein important for health?

A: Outside of supporting the growth and repair of muscle tissue, it supports the immune system & facilitates various metabolic processes. It also assists with the transportation of nutrients, maintaining fluid balance & in more extreme situations, can even be used by the body as an energy source.

Q: How quickly does protein help repair muscle?

A: Muscle protein synthesis increases within hours of consuming protein and typically peaks around the 3-4 hour mark.

Q: How quickly does protein absorb?

A: Typically the complexity of a meal (the combination of proteins, carbs & fats) will influence how quickly it is digested, however whey protein supplements can be rapidly digested and absorbed into the bloodstream within 60-90 minutes. More complex meals will likely take longer than this, because it’s a more thorough job that the body needs to complete.

Q: Does protein help with energy?

A: Whilst protein isn’t a preferred fuel source, it can help with stabilising blood sugar & supports metabolism. Under extreme circumstances it can also be used for energy (when the body is out of more readily available energy sources like carbs & fats).

How Protein Powder Can Help You Reach Your Protein Goals

Getting enough protein in through food sources alone at times can be tough. Supplementing with a protein powder/ supplement is often easier, cheaper & more convenient than cooking a steak or some chicken (foods high in protein).

Not only that, but by supplementing with a high quality powder that is fast-absorbing, you can also ensure you’re always getting a high quality serving of protein in a convenient fashion - free from having to worry about the need for a frying pan..

Why choose a high quality protein powder like Optimum Nutrition Gold Standard 100% Whey? The number one ingredient is whey protein isolate, which is fast-digesting to help with faster recovery, it’s trusted by athletes worldwide, mixes easily & comes in over 15 flavours.

Final Recommendations

Protein is often spoken about as THE thing for lifting weights, building muscle and getting strong - but in reality it is important for so many reasons more than just that.

Protein plays a vital role in just about every aspect of your health, from muscle growth and repair, to your metabolism, your immunity & your overall wellbeing. Whether you’re looking to get stronger, leaner or simply prioritise your health as you age, prioritising your protein intake is arguably one of the most impactful things you can do for your health in the long term.

For more information on the various types of protein powders & how they can specifically support your goals, check out our popular article covering the ‘Best Protein Powders’ HERE

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