Flatlay of different proteins, including chickpeas, cheese and veg

The best protein sources: does it matter if you eat animal protein or plant protein?

Posted by for Nutrition

We’re frequently told to eat more protein if we want to build muscle, but does the source of your protein intake matter? 

You’ve no doubt been told that protein is the key ingredient when it comes to building muscle and gaining strength. In fact, the macronutrient is often thought of as being the foundation of muscle growth

But according to a paper published last year in the Elsevier Reference Collection, the western diet is characterised as being rich in saturated fats, refined carbohydrates and salt. This means that for those of us trying to build muscle, prioritising protein can feel challenging. 

As a result of people trying to find creative ways to incorporate more protein in their diets, we’ve witnessed the rise of TikTok ‘profee’, the protein overnight oats trend and even people trying dry-scooping protein powder (yikes) over the past couple of years.

Are all proteins made equal?

We’ve reached a stage where it’s now possible to buy a protein-enhanced version of virtually anything. And with so many options available, this leads us to ask: does it really matter where you get your protein from? 

New research by the American Heart Association suggests it does. In the study, researchers counted how many different sources of protein participants ate from whole grains, refined grains, processed red meat, unprocessed red meat, poultry, fish, egg and legumes. Those who had the highest variety of protein sources had a 66% lower risk of developing high blood pressure, suggesting that protein variety is the key to health.

But how do protein sources differ when it comes to building muscle? Protein molecules are made up of building blocks called amino acids. These are used by our bodies to rebuild muscle fibres which are broken down when we exercise. Each time these fibres are broken down and rebuilt, our muscles become stronger and more able to handle similar physical activity in the future.

There are two distinct categories of amino acids: amino acids that the body cannot produce itself are called essential amino acids (EAAs), while amino acids that the body can produce itself are called non-essential amino acids (NEAAs).

Most animal proteins are considered “complete proteins”, which means that they contain all nine of the EEAs that we need. Most plant proteins are considered incomplete proteins, which means that they miss at least one EEA.

“To build muscle size and strength requires the ingestion of protein that contains an optimal ratio of these EAAs. One EAA, leucine, has an especially important role in muscle growth,” explains Antonia Osborne, a nutritionist and health coach at Steve Grant Health.

Leucine is responsible for telling your muscle fibres to use amino acids to grow. It is found in high quantities in foods including salmon, chickpeas, brown rice, eggs, soybeans, nuts and beef. 

For those who opt for a plant-based diet, meeting a specified daily protein goal can feel challenging. Studies have shown that plant-based protein sources generally have a lower leucine content – approximately 7.1% – than animal-based protein sources, which have approximately 8.8%, and even more than 10% in certain dairy proteins.

“Plant-based proteins also contain substances called anti-nutrients, which reduces the amount of protein – amino acids – available post-consumption. This means that you have to intake a higher dose of plant-based protein to have a similar effect on muscle growth,” says Osborne. “To match the leucine content of dairy proteins, individual plant-based proteins must therefore be consumed in higher doses of around 50-60g.”

Interestingly, papers like this one, published in the Nutrition Journal, have also shown that when leucine levels are matched, animal-based proteins and plant-based proteins have similar effects on promoting muscle growth. 

Protein supplements versus whole foods

The global sports nutrition and supplements market has exploded over the past few years, from a value of $13.9 billion (£10.31bn) in 2018, to a predicted $35.35 billion (£26.22bn) by 2025.

Once considered a niche product reserved for bodybuilders, protein-enhanced snacks and supplements are now found on the shelves of almost every mainstream supermarket. Meanwhile, specialist shops such as Protein Pick and Mix in Tunbridge Wells are offering consumers virtually every high-protein snack imaginable.

“Protein supplements – such as powdered shakes – provide a convenient, easy and cost-effective way to get a guaranteed amount of protein into the diet,” explains sports nutritionist Lindsey Ormond of LO Health Solutions. “These are designed to supplement the diet, rather than replace whole foods – unless in the case of meal replacement products.”

While protein supplements can be useful in providing us with a convenient source of protein, they can also lead us to miss out on vital nutrients. Many ready-to-drink protein shakes also contain unwanted ingredients, such as sugar and artificial flavourings.

Even “sugar-free” drinks can contain high quantities of sweeteners. This means that a person with diabetes should check the sugar content carefully before purchasing these drinks. Similarly, those who are lactose intolerant should avoid supplements that contain whey and casein, since they both come from milk.

“Whole food sources of protein result in a more prolonged response of protein availability with less of an initial peak. Whey protein, on the other hand, results in more of a rapid peak in protein availability and a quicker return to baseline,” Osborne says.

Whether this rapid rise in protein availability versus a prolonged response is superior for muscle growth provides any benefit remains unclear and requires further research. One thing that is clear, however, is that protein distribution does matter, given that there is a cap on how much that our body can utilise at a given time. 

How to work out your own protein needs

“The western diet tends to skew protein intake to the evening meal, but good breakfast options include high protein yoghurt, eggs, tofu or protein powder added to a smoothie,” says Ormond. “Spreading protein intake throughout the day is optimal for keeping you fuller for longer and maintaining your muscles. Aim for 20-30g at each meal and after intense exercise sessions.”

When it comes to figuring out how much protein you should be eating each day, Ormond recommends using a protein calculator.

“A common misconception is that protein intake higher than the RDA (recommended daily allowance) is a waste or is bad for you,” she explains. “RDAs are set to prevent deficiency, rather than be the optimal level.”

It’s also important to note that not everyone needs a high-protein diet, and there are some people for whom a high-protein diet is not suitable – such as those with kidney disease, whose bodies may not be able to eliminate all the waste products of protein metabolism.

It can be easy to overthink when it comes to tracking food, so don’t put too much pressure on yourself. As long as you try to eat a balanced diet that contains a good balance of protein-rich foods, and you make an effort to spread your protein intake throughout the day, you’re doing great.

Remember, even with the right amount of protein and a rigorous training routine, building a strong body takes years – not weeks or months. 

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Images: Getty

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