Whey Protein: What It Does and Why You Need It


Get the lowdown on whey protein: what it is, how it's made and whether you should be taking it

Max Anderton
5 Oct 2015

Whey protein is the most important muscle-building supplement you can take, with essential benefits for everyone from casual gym-goers to elite sportsmen. But with so many choices, each with a variety of other substances and bewildering acronyms propping up their ingredients list, it can be difficult to know what you’re actually putting into your body - or if it’s even helping your training. Here's what you should look out for next time you reach for the scoop...

Production process

Both isolate whey and concentrate go through a microfiltration process – basically a really fine sieve – but isolate goes through it more times. This produces a powder containing more than 90% pure protein, compared with around 75-85% for concentrate.

Protein type

Take whey straight as soon after a workout as possible for a quick hit of muscle-building nutrients. Casein is the bedtime protein, and you should take it before you hit the hay for a prolonged release of protein to aid muscle recovery and growth. Soy protein is a vegan option derived from soya beans, and studies have shown that it, like the previous two, supports muscle hypertrophy.

Everything you need to know about protein powder

Brand power

With so many companies making whey protein powders, it can be tricky knowing which to go for, specially considering the difference in prices between certain brands. While more expensive brands usually use isolate whey, rather than concentrate, that's not always the case so it's worth reading the product description to find out. As a rule of thumb, check how long the brand has been around for. If they've been trading for ages, it’s a safe bet it’s a decent product. Having said that, most companies use the same – or very similar – protein in their products, it's the flavour (and carbohydrate content) that drastically changes between different products.


You might find these in your protein powder, and for good reason. If you're training with heavy weights, branched-chain amino acids help prevent the breakdown of muscle tissue and post-workout DOMS (delayed onset muscle soreness) so you recover quicker and can train again sooner. Sometimes called the 'building blocks' of the body, BCAAs comprise 35% of your muscle tissue and are needed in order for them to repair and grow. Eight of them are essential, which means your body can't make them, while the rest can be produced by your body. Besides repairing tissue and helping to build new cells to aid growth, BCAAs form antibodies and even help carry oxygen in your bloodstream. Their primary function is to carry nitrogen, which is needed to be able to combine simpler amino acids into new muscle tissue. In short, they are vital for proper recovery and msucle growth post-exercise.


You could find this in your protein, most likely if you have a bulking powder. What it does is increase energy, which allows you to train for harder and longer. This means protein synthesis (muscle fibre repair) will occur more, building bigger muscles.

Find out more about creatine

Carb content

World-renowned strength coach Charles Poliquin says that if you’re going for mass gains, you must take a protein and carb-rich shake after your workout. For lean gains, avoid excessive carb intake and simple carbs even more so. Low carbs in your diet means a drop in the body’s insulin, making it easier for your body to burn fat.


There is no general agreement to how much protein you should be taking after a workout. Poliquin says that 0.55g of protein per kg of bodyweight is enough for building muscle. So for a 75kg man looking to accelerate his strength gains, around 40g of protein per post-workout serving should hit the spot.

The science

A study published in the Journal Of The International Society Of Sports Nutrition found that subjects who consumed whey protein after training experienced improved blood flow to their forearm muscles, enhancing the delivery of muscle-building nutrients such as oxygen and hormones. It is also generally understood that the anabolic effects of weight training are increased through the consumption of whey protein because amino acids are rapidly driven to skeletal muscle tissue. This helps your muscles get larger and stronger in less time than if you weren’t taking whey protein

A definitive guide to protein shakes

Strawberry super smoothie

Of course, you can always blend other ingredients into your post-workout protein shake to add variety and pack in other nutritional benefits. Try this protein smoothie, designed by nutritionist Scott Baptie. It hits three of your five a day, tastes delicious and has even more good stuff to ensure you get the most from your hard work in the gym.


1 scoop whey protein
Whey protein 
is essential for building and repairing muscle after a workout.

Handful of strawberries
Strawberries are a source of anthocyanins that can improve focus and boost short-term memory.

½ avocado
 are high in soluble fibre, which can help to reduce spikes in blood sugar that cause you to put on weight.

50g spinach
is rich in iron, which helps you maintain high energy levels.

10g honey
is a natural carbohydrate source that provides energy-boosting fuel for the body.

Water (to taste)
keeps you hydrated – just 1% dehydration can lead to a 10% reduction in workout performance.

This content is from the experts at Men's Fitness magazine.

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