Why is everyone raving about protein coffee?

Exercise physiologist and nutrition scientist Dr Stacy Sims was recently on Mel Robbins' podcast explaining the protein-laced coffee brew she downs first thing in the morning.

An Instagram video Dr Sims made in her New Zealand home showing how to make her chilled 'proffee' the night before was viewed more than 20,000 times in just three minutes.

"I am laughing that it has become such a trend," says the popular American-born author of the pre-workout drink she's been making for several years now.

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"I was like, how do people not know how to make this? All you do is you stir protein powder into cold milk and then you put in a double shot of espresso and you put it in the fridge and you're ready to go? And people were like, 'oh my God, this is amazing'."

Brittany McNabb, a personal trainer in Auckland with a background in psychotherapy, says it's a hack that has worked well for clients looking to lose weight or build muscle. She has been drinking it for years too.

"I originally started it as a way to get protein in quickly first thing, especially on busy mornings, and coffee was already part of my morning routine, so it just made sense to habit stack."

Dr Sims says the idea behind a proffee is mostly convenience - you could still have your cup of coffee and protein separately.

"When you're looking at like caffeine use and how it helps delay fatigue during exercise and helps mobilise more fatty acids for exercise, it makes sense to have some caffeine before. And then the protein is because you need some nutrition before you train and it also helps taper that jittery response that people will get from coffee and caffeine."

McNabb says the mix is particularly helpful for people who are not getting enough protein or are working out while fasting, which is counterproductive for muscle build and weight loss.

"You’re getting in leucine (the key amino acid that triggers muscle protein synthesis) from the protein, and caffeine from coffee can support alertness and even help mobilise fat when timed right with training."

However, Dr Ali Hill, who has researched sports nutrition at the University of Otago, says you may already be getting a good source of protein with your coffee if you're adding milk.

"We know that protein plays an important role in recovery and building strength, and the caffeine in coffee can boost performance. But we don’t know that having them both together in large amounts has the same or better effect. Or even if it’s worse than having them separately."

You may also not get the desired effect if, for example, you're used to having large amounts of caffeine, she says.

McNabb recommends blending 25–30g of whey protein, or a well-formulated plant blend, with a double shot of coffee, half a cup of unsweetened almond milk and quarter cup of water. If you want it chilled, throw in half a cup of ice.

She suggests using a blender and avoiding hot water to prevent clumping. You can also customise it with ingredients like collagen, cinnamon, a scoop of Greek yoghurt or some frozen banana.

"Ideally, have it within 30 minutes of waking. That’s when cortisol is high and your body needs protein to buffer us against stress."

Dr Hill says caffeine before a workout might help you go that extra mile but as for protein, you should consider getting some after exercise as well for strength gains.

"When we have protein after exercise, it slows down the rate we break down proteins, whilst at the same time increasing the rate at which we make new ones. This is really important as it helps us build muscle after exercise.

"But protein isn’t the only thing we need after exercise. Having carbohydrate helps restock our energy stores. And having a drink is important to replace any fluids you’ve lost from sweating."

McNabb recommends the drink for anyone who struggles to eat early in the morning or wants an easy "low-lift" to hit protein targets. The full benefits, however, are not realised until you combine it with some exercise, she says.

Dr Hill believes most people are getting enough protein in their diet anyway, and if you’re not exercising, it probably isn’t something you need to worry about.

People who should be wary of the caffeine are pregnant or breastfeeding women and people with heart problems. Those who have kidney issues also need be cautious of high protein intake, she says.