Protein is a key nutrient for building muscle and gaining strength. In fact, the macronutrient is often thought of as being the foundation of muscle growth. 

But many of us are still confused over where exactly we should be getting our protein from. Head onto social media, and you’ll find one PT telling you to eat 12 eggs for breakfast and plenty more pressing home the importance of protein powders or plant-based nutrition. 

We’re obsessed by the idea that we’re not able to get enough protein from diet alone, and for anyone who does eat a typical Western diet that’s high in refined carbs, saturated fats and salt, that might be the case. As a result, we’ve seen all kinds of protein trends come and go, from TikTok’s ‘profee’, to protein overnight oats trend and dry scooping (yikes!).

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? 

Increasingly, the research suggests yes. Research published in The American Journal Of Clinical Nutrition found that women who consume higher amounts of protein – especially from plant-based sources – develop fewer chronic diseases and are more likely to be healthier overall as they age.

A couple of years ago, the American Heart Association presented a paper that suggested that eating a range of different protein sources could also be helpful. They found that people who 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.

Those studies might sound like they contradict each other, but the key here is about eating a varied, balanced diet which allows you to get the full gamut of amino acids – the building blocks that make up protein molecules. 

Our bodies use amino acids 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 – but different plants contain different EEAs. The more sources of plant protein you eat, the more likely it is that you’ll be eating complete proteins. It’s for that reason you’ll see lots of vegan protein blends mixing soy and hemp, or brown rice and soy compared to bog-standard whey. 

“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. 

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.”

Once those leucine levels are matched, however, research has found that animal-based proteins and plant-based proteins have similar effects on promoting muscle growth. 

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. 

“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, however, they can also lead us to miss out on vital nutrients (usually fibre).

“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.

“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.

“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 (like people with kidney disease). The key, as ever, is having a balanced diet that contains a good balance of protein-rich foods and spreading those nutrients throughout the day. If you’re eating enough fibre from lots of different plants, you’re already half-way there.

Images: Getty