The Science Behind How Much Protein You Need

Savoury corn waffles with poached eggs

Knowing how much protein to consume can be difficult. There’s a lot of conflicting evidence around protein intake, and your requirements can be affected by individual differences, such as age, sex, exercise, height and so on.

As it stands, the Recommended Nutrient Intake is approximately 0.75g per kilogram of bodyweight. This translates to around 56g of protein a day in a 75kg person.

However, as mentioned above, your requirements can change with various factors.


If you partake in regular sport and exercise (above the government-recommended 150 minutes of moderate exercise a week), then you will likely require a higher protein intake than someone more sedentary. This generally encompasses anyone that does regular strength and or endurance training, such as running, cycling or weight lifting, as more protein is required to promote muscle tissue growth and repair.

In this situation, protein requirements increase to 1.2-2.0g protein per kilogram of bodyweight per day. This works out as 90-150g protein a day in a 75kg person – substantially higher than those who are sedentary.

Protein Source Protein (g) per 100g Raw weight (g) or 75g protein Raw weight (g) for 90g protein Raw weight (g) for 150g protein
Chicken Breast 31 242 290 484
Beef (Ground; 85% Lean Meat) 26 288 346 577
Salmon 20 375 450 750
Tempeh 19 395 474 789
Egg 13 577 692 1154

Table 1 – Comparison of Protein (g) from Different Sources

The above table illustrates the quantities needed of various protein sources to reach the ranges mentioned, based on a 75kg person. It should be noted that protein also comes from various vegetable and carbohydrate sources that would often accompany these primary protein sources.

Older people also require a slightly higher intake than the average person, with recommended amounts being from 1.0-1.2g per kilogram of body weight (75-90g total for a 75kg person). This is because as we age, our bodies become less efficient processing protein, and so we require more of it to maintain muscle mass and strength, as well as many other physiological functions.

Even if older people are healthy and active, they still require more protein than when they were younger (even when matched for similar exercise habits).

Complete Proteins

Protein is a macronutrient, made up of amino acids, which act as ‘building blocks’.

There are 20-22 different amino acids commonly found in plant and animal proteins. Nine of these are considered ‘essential’, meaning the human body cannot synthesise them from scratch, and they, therefore, must be obtained from the diet – these are commonly sourced from animal products, such as meat, fish, eggs and dairy.

These protein sources all contain different amounts and combinations of amino acids – animal sources of proteins contain all the essential amino acids required by the body.

That’s not to say that vegetarians and vegans cannot obtain the full range of amino acids – they just need to ensure they are combining different sources of plant protein. This typically involves combining a protein source, such as peanut butter, with a carbohydrate source, such as a wholewheat bread – combining pulses and cereals in one portion to provide a ‘complete’ protein.

There are also a number of vegan sources of complete protein, such as quinoa, buckwheat and soybeans, but it is great to vary your food sources where possible so that you are consuming other essential nutrients.

Muscle Protein Synthesis

meatballs with sweet potatoBuilding muscle is a key goal for many FFF clients, and the amount of protein required to hit this goal is often in question.

While the specific amount, of course, varies from person to person, and with age, muscle mass, and so on, evidence shows that there is peak muscle protein synthesis response with 20-30g of protein per portion.

However, there is no identified upper limit of protein, and overall protein consumption throughout the day seems to be the most important factor in building muscle. Furthermore, the minimum recommended amount of protein also increases with age and weight.

Many believe that excess protein will lead to instant fat gain, and while not all protein will be used to synthesise new muscle, excess protein can decrease whole-body protein breakdown, essentially meaning that muscle mass will not decrease with excess protein, and therefore will not be ‘wasted’. However, ensure that you are consuming carbohydrates and fats, too, and not just protein!

Essentially, to build muscle, you need to be consuming enough protein and calories to maintain the muscle mass you already have, and then on top of that, enough to actually synthesise new muscle tissue.

Fresh Fitness Food provides personalised meals plans delivered straight to your door, ensuring not only that you have the nutrients you need to manage your stress levels, but also that you have the time usually spent shopping, cooking and washing up, to engage in your favourite stress reducing activity. To discuss which nutrition plan is right for you, book a call with our in-house nutrition team here.

Order today and start smashing your goals with personalised nutrition!

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