Why Your Body Needs Protein Regularly

Protein has had excellent PR for a very long time. Long before modern whey protein and other protein powders, early nutrition scientists were already describing protein as the ‘only true nutrient’ [1]. In fact, the name ‘protein’ came from the Greek word ‘proteios’ which meant ‘of first rank’ [2]. And to be fair, protein is unique and important – both of which we will come to discuss. But the story is more nuanced than simply more equals better. Why your body needs protein – let’s dive in:

Can you store protein like carbohydrates or fat?

Carbohydrates and fat two of our body’s main energy sources. When we eat more carbohydrate than our body needs at that time, it can be stored as glycogen in the liver and muscles. Fat can be stored in adipose tissue [3].

Protein is different. The body contains plenty of protein, forming part of muscle, bone, structures and enzymes [4]. But this is functional tissue rather than a dedicated protein ‘storage space’ that can be dipped into when lunch is late [5].

So, when we eat more protein – which is then broken down into amino acids – than the body needs at that time, the nitrogen-containing part is removed and excreted, while the remaining carbon component can be used for energy or converted into other compounds [6,7,8].

This is one reason why we need a regular supply of amino acids from the diet. Not obsessively, but consistently enough to support the ongoing turnover of body proteins. Talking of which…

Protein Turnover

A bit like renovating a house while still living in it, the body is constantly removing old materials, recycling what it can, and building new structures. This process is called protein turnover: the continuous breakdown and rebuilding of body proteins [9].

Some proteins turn over quickly, while others more slowly. But overall, the average rate at which the body rebuilds protein is estimated to be much higher than the amount of protein we eat each day, because many amino acids are recycled internally [10,11]. So, although dietary protein matters, the body is also very good at reusing amino acids from the breakdown of existing proteins!

So, how much protein do we need?

In the UK, the adult Reference Nutrient Intake (RNI) for protein is 0.75 g per kilogram of body weight per day [12]. This is a recommendation designed to meet the basic needs and prevent deficiency for most healthy adults [13]. The RNI gives a useful baseline, but optimal protein intakes will vary greatly depending on age, body size, health status, activity levels, and goals.

For active adults aiming to build or maintain muscle, one meta-analysis found that protein supplementation up to 1.6 g/kg/day – but not beyond – in healthy adults appeared to support fat-free mass gains when paired with resistance training [14,15]. This isn’t to say every active adult needs that amount, but rather to highlight there may be a ceiling beyond which more protein is unlikely to add much, especially without progressive training.

Our innate drive for protein

There is a theory in nutrition science that humans may have a biological drive to eat enough protein. This is known as the protein leverage hypothesis [16].

It’s based off the work of David Raubenheimer and Stephen Simpson which suggested animals – including humans – appear to have an ability to sense when a nutrient (like protein) in their diet is low and seek foods in attempt to make up for the shortfall (e.g., seek high-protein foods until their protein needs are met).

More recent work has also suggested that a protein called FGF-21 may be secreted by the liver in response to low protein intake and signals this to the brain, potentially increasing our preference for protein-rich foods [17].

In today’s food environment, this theory becomes especially interesting, as if someone’s diet is rich in ultra-processed, energy-dense foods that are relatively low in protein, it may be easier to consume plenty of calories before protein needs are met. This is one proposed way protein leverage could contribute to higher energy intake [22,23].

Human research offers some support for the theory, although findings are not perfectly consistent. In controlled feedings studies among adults, lower-protein diets were associated with higher total energy intake compared with higher-protein diets [24,25]. In free-living children and adolescents, lower protein percentages have also been linked with higher energy intake [26].

Of course, this is not to say that protein is the only thing controlling appetite – energy needs, stress [18], hormones [19], food environment [20], sleep, meal timing [21] and much more can all influence appetite. But protein may be one piece of the appetite puzzle.

What does this mean practically?

The practical takeaway is refreshingly simple:

Protein-rich foods are important and can help meals feel more satisfying, especially when paired with fibre-rich carbohydrates, healthy fats and plenty of plants [27,28,29]. But don’t assume more is always better. Instead, include a protein source at each meal, and for individuals with higher needs, or when meeting enough protein through meals alone is difficult, this is where protein powders and protein-fortified products can be a convenient option.

The goal is not to chase protein for its own sake; it’s to support a diet that is adequate, enjoyable and balanced.

Disclaimer:

The information in this article is based on current scientific evidence and is intended solely for educational and informational purposes for the general adult public. The content reflects general principles and knowledge within nutritional science and should not be used as tailored dietetic advice. Any product links and promotions do not constitute specific endorsements from me as a healthcare professional. Readers should consult an appropriate healthcare professional before making significant dietary changes or beginning supplementation, particularly if they have an underlying medical condition or take prescribed medication.

Meal Shakesexpand_moreMeal Shakes

Protein Powdersexpand_moreProtein Powders

Vegan Shakesexpand_moreVegan Shakes

Weight Loss Shakesexpand_moreWeight Loss Shakes

Muscle & Gainer Shakesexpand_moreMuscle & Gainer Shakes

Health & Wellnessexpand_moreHealth & Wellness

Focus & Energy Shakesexpand_moreFocus & Energy Shakes

Accessoriesexpand_moreAccessories

Breakfastexpand_moreBreakfast

Sweetexpand_moreSweet

Savouryexpand_moreSavoury

Nut Butters & Spreadsexpand_moreNut Butters & Spreads

Feel Betterexpand_moreFeel Better

Health & Wellnessexpand_moreHealth & Wellness

Weight Lossexpand_moreWeight Loss

Creatineexpand_moreCreatine

Collagenexpand_moreCollagen

Vitamins & Mineralsexpand_moreVitamins & Minerals

Pre Workoutsexpand_morePre Workouts

Omega 3expand_moreOmega 3

Protein Turnover

So, how much protein do we need?

Our innate drive for protein

What does this mean practically?

Disclaimer:

References:

Related Posts