Guest article from Personal Trainer, Food Enthusiast and Mac-Nutrition Uni student, Sammy Cooper of Sammy’s Kitchen. Check out @sammyskitchen on Instagram for fitness and recipe advice.

There are three macronutrients which make up the bulk of nutrients:

  • Protein
  • Carbohydrate
  • Fat

All three play important roles in all aspects of life, from everyday movements and biological processes, right up to exercise performance and hormone regulation. In this article, we’re going to take a look at the role of dietary protein, do a bit of myth busting, discuss the benefits that a high protein diet can bring, and more importantly; how these can be applied to your diet.

What is protein and why is it important?

Protein is made up of amino acids – 11 non-essential and 9 essential. The essential amino acids are the ones we cannot make ourselves, so have to get them from what we eat.

Protein can be seen as the building blocks of the body – it is an essential requirement in almost every bodily function. From hair and nail growth to muscle hypertrophy and immune function, protein is a key part of our diet, no matter our activity level, gender or age.

In addition, protein can also be converted to use as energy when nutrition is not sufficient or during extreme exercise.

Protein is an essential requirement in almost every bodily function

Complete vs Incomplete Proteins

Complete proteins are those that contain all the Essential Amino Acids (EAA) in adequate amounts. All animal-based protein sources are complete proteins, such as:

  • Meat
  • Fish
  • Yogurt
  • Milk
  • Eggs

… and more.

Plant-based proteins are generally incomplete proteins, meaning they are deficient in at least one EAA. However, there are a few plant-based protein sources that contain all the EAA’s (e.g. soy and quinoa) but they are in much smaller quantities than animal-based products. This is why combining food sources is particularly important for vegetarians and vegans, so that the incomplete sources complement each other, ensuring all EAAs are incorporated into the diet over the course of the day.

Protein myths busted

Myth: Too much protein is bad for your kidneys.

There is no evidence to suggest any adverse effects on renal function in healthy people, or any other negative impacts in general. Although excessive amounts of protein haven’t been proven to directly have harmful effects, it will do if it means we are sacrificing other nutrients. There are 4kcal in every 1g of protein (the same amount as carbohydrates, and 9kcal in fat), so if we are excessively consuming protein within our total daily energy intake, it may mean we are limiting our intake of other vital nutrients.

Myth: There is more protein in broccoli than steak, so broccoli is an adequate replacement.

It is true that there is more protein per kcal in broccoli than in steak – there are 9g of protein in 100kcal of broccoli, and only 7g in the same amount of steak. However, to hit 9g worth of protein just from eating broccoli, you would need to eat 0.77kg of the stuff… that is a LOT of broccoli! Three quarters of a kilo of broccoli, to be precise, instead of a 5.5oz steak!

Myth: Whey protein powder is just for gym-goers, and must be consumed as soon as you finish your workout while still at the gym.

Whey protein is simply just dairy! It isn’t really considered a supplement, more of a performance food or just an easy and convenient way to hit your protein targets. It is a low calorie/high protein option, and one that can be used by all, whether you’re a pro athlete or just trying to lose weight. They don’t need to be drunk as soon as you finish your workout, but can be a convenient way to get some protein on board if you won’t be eating a meal within the next 60-90 minutes, or are simply looking to increase your total protein intake.

Health benefits of protein

Muscle growth and strength training

Just as a sports massage might be part of your recovery protocol during a training programme, a high protein diet will be hugely beneficial too. Protein supports muscle adaptations following resistance training, and increases muscle recovery.

Protein is essential in order to aid muscle growth

Leucine is an EAA that stimulates the process in which we build muscle, known as Muscle Protein Synthesis (MPS,) making it a particularly important component if you are exercising or looking to build muscle. There is a leucine threshold that we must hit in order to stimulate MPS, which equates to around 20-25g of total protein from a complete protein source (e.g. chicken, dairy etc). Spreading your protein intake evenly throughout the day will enable you to maximise the MPS stimuli. For example, aiming for 20-25g+ at each meal will be more advantageous than one meal with 60g of protein, and two with 10g, as we stimulate MPS three times rather than once. It is important to note that total protein bares a greater weight than frequency, so focus on this if the frequency seems overwhelming.

Fat loss

High protein diets have been linked to fat loss time and time again. When compared to low protein diets, there are numerous studies that show greater weight loss, fat loss, BMI, waist circumference and blood pressure improvements.[1] This is likely down to a few reasons, including:

  • Satiety
  • Thermic effect of food
  • Ability to aid muscle retention.

Protein is the most satiating macronutrient, which makes you feel fuller – more so than carbs or fats. With hunger often making people spontaneously increase their energy intake making it detrimental to fat loss, the satiety of protein is a hugely beneficial component and can help decrease ab libitum food intake[2]. It also has a high thermic effect, which relates to the amount of energy needed to digest it. Up to 30% of the energy (calories) in protein are used just to digest it!

High protein diets can be heavily associated with weight loss

Protein, along with resistance training, aids our ability to maintain fat free mass. As well as the obvious benefits of muscle retention, maintaining our fat free mass will have a positive effect on our Basal Metabolic Rate (BMR), which is the number of calories we burn for everyday processes – total calories we’d burn if we were to do nothing but lie in bed all day. Our BMR decreases as we lose weight (both fat and muscle weight), so a high protein intake can help maintain our muscle mass, preventing our BMR from reducing as much which allows us to burn more calories by simply doing nothing!

Although there are numerous benefits of a high protein diet for fat loss, it must be noted that the only way to burn fat is to be in an energy deficit – consuming less energy/calories than you are expending. It is important that this is done in a safe and sensible way. If you are considering this, seek the guidance of a professional nutritionist or healthcare expert in order to ensure that you are approaching this in a healthy and balanced way.

Age related muscle wastage

Sarcopenia is the degenerative loss of muscle mass and strength, which creates an increased risk of falls in the elderly. As mentioned above, protein plays a vital role in maintaining muscle mass, and along with resistance training, can make this condition preventable.

However, as we get older, our bodies require a larger quantity of protein in order to stimulate MPS. We become less sensitive to protein as a stimulus for muscle growth and repair[3], meaning we need to take on larger quantities to maintain the same level. This makes high protein diets of greater importance the older we get.

How much protein do I need?

The RNI of protein is a mere 0.8g/kg of bodyweight (e.g. an 80kg person should be aiming for 64g of protein a day), however these recommendations are widely considered on the low side by most professionals in the industry, and should be taken as the absolute minimum to avoid deficiency[4]. So, how much should we really be eating?

  • Sedentary/general population – 1.2-1.6g/kg of bodyweight
  • Endurance athletes – 1.2-1.7g/kg of bodyweight
  • Fat loss (with resistance training) – 1.6-2.2g/kg of bodyweight
  • Muscle growth – 1.8-2.7g/kg of bodyweight

For example, for a 65kg individual that is 78 – 125g of protein, or for someone who is 80kg: 96 – 128g.

Where do I get my protein from?

  • 100g Chicken breast ~33g protein
  • 100g tinned tuna ~27g
  • 100g of Greek yogurt ~7-9g
  • 3 large eggs ~21g protein
  • 25g whey protein ~21g protein
  • 2 Light Babybel ~10g
  • 200ml skimmed milk ~ 7g protein
  • 200 ml soya milk ~ 6g protein
  • 100g red lentil pasta ~23g protein
  • 70g tofu ~11g protein
  • 100g edamame beans ~14g protein
  • 200g tin no added sugar baked beans ~ 9g protein

The take-homes

Protein plays a vital role in every day function, aids muscle growth, fat loss and age-related muscle wastage. Remember:

  • Recommended intake should be based on body weight and activity levels.
  • Aim for 20-25g+ of complete protein 4 times a day to maximise MPS. Consuming double that amount in your last meal of the day will slow down Muscle Protein Breakdown (MPB, the opposite of MPS) throughout the night while you sleep.
  • Total protein intake is more important than frequency.
  • Protein counts towards your overall calorie intake.

Sammy Cooper is a Personal Trainer and Mac-Nutrition Uni student, offering training plans and PT sessions in Harpenden. Find out more by following @sammyskitchen on Instagram.

[1] Wycherley et al (2012), Santesso et al (2012)

[2] Skovetal (1999)

[3] Penning et al 2012

[4] Kwashiorkor, Williams 1935