As trainers, we hear more about protein than any other nutrient. Clients ask if they need to eat more of it. They ask if protein shakes are necessary. They ask if eating a whole chicken after leg day is really going to help. And they’re not wrong to focus on it, protein is essential, especially when it comes to recovery, training adaptation, and overall performance. It’s also one of the most common questions asked in our nutrition courses. But it’s not just about hitting a daily gram target. It’s about when and how that protein is consumed.
Let’s take a look at why protein matters so much, what recent research tells us about its timing, and how we as trainers can use this to better support our clients.
Why Getting Enough Protein Is Essential
Protein is made up of amino acids, the building blocks of muscle. During and after exercise, especially endurance or resistance training, the body enters a state where muscle proteins are broken down (muscle protein breakdown or MPB). To counteract that, we need muscle protein synthesis (MPS), the process of rebuilding those proteins. Protein in the diet, particularly essential amino acids like leucine, is what triggers MPS.
During endurance exercise, muscles also burn some amino acids for fuel, particularly the branched-chain ones (leucine, isoleucine, valine). So we’re not just talking about rebuilding muscle, we’re also replacing what’s been burned as energy. This is why endurance athletes, and clients doing a lot of cardio or long sessions, often have higher protein needs than they realise, something often overlooked unless you’ve studied it in a nutrition course.
This repair and rebuilding process doesn’t just happen in the gym. It continues for hours after training and it needs fuel to do its job. That fuel is protein.
Protein Powders
Protein powders are an easy and convenient way for clients to increase their intake. They’re especially popular because they tick all the boxes: fast-digesting, easy to carry, and usually cost-effective per serving. For people who struggle to get enough protein through food alone, or who train early in the morning or late at night, protein shakes are the easy solution.
But convenience often leads to over-simplification. Many clients will chug a shake after training and assume the job’s done. But it’s not quite that simple. Yes, protein powders can help meet daily targets, but they need to be used smartly and as part of a wider strategy that includes timing, quality, and total intake.
The Study That Changes How We Think About Protein Timing
A recent study published in Sports Medicine (Witard, Hearris & Morgan, 2025) set out to provide an updated look at the protein needs of endurance athletes. While the focus was on endurance training, the findings have clear implications for anyone doing regular, intense training.
The researchers reviewed high-quality metabolic studies, particularly those using a method called “indicator amino acid oxidation”, a clever technique that shows how much protein the body is actually using to build and repair tissue. Unlike older methods like nitrogen balance studies, which often underestimated protein needs, this newer approach gives a clearer picture.
What they found was fascinating! Endurance athletes need more protein than we’ve long assumed, up to 1.8 g/kg body mass per day on regular training days, and even more, 2.0 g/kg, on recovery days or during carb-restricted sessions. But what really stood out was how much timing matters.
Not Just How Much, But When
The study found that the per meal dose of protein was just as important as the total daily intake. To support muscle protein synthesis effectively, endurance athletes should aim for around 0.5 g/kg of body weight in each protein feed after training. For a 70kg client, that’s about 35g of high-quality protein post-exercise. And this needs to happen soon after training, when the muscle is primed for repair.
Interestingly, when protein is consumed during the actual workout, there doesn’t seem to be much added benefit for performance or muscle recovery, unless carb intake is too low. The real gains come from getting the right amount of protein after training and again regularly throughout the day to support ongoing repair and adaptation.
What We Can Do with This Info
For us, it means we can go beyond the generic advice of “eat more protein.” Instead, we can coach clients on when to eat it, how much they need at each point in the day, and what kind is best.
Here’s a breakdown to help clients get it right:
| Training Context | Protein Intake Target |
|---|---|
| Standard training day | 1.8 g/kg/day |
| Recovery or low-carb day | 2.0 g/kg/day |
| Post-exercise (per meal) | 0.5 g/kg within 1 hour post-training |
| Intense training week | Up to 3.0 g/kg/day (short-term only) |
| Low appetite after training | 0.4 g/kg with carbs to help recovery |
For Example: Let’s say you have a 70kg runner doing a 90-minute session. Post-workout, they should aim for 35g of protein within the hour. That could be:
- A shake with 30g whey and a banana
- A chicken wrap with hummus and spinach approx.. 38g protein
- Greek yoghurt with oats and berries – approx.. 26g protein
If they’re in a recovery phase or doing back-to-back sessions, their total protein for the day might need to be closer to 140g , which means spreading protein-rich meals and snacks throughout the day.
Getting the Right Type of Protein
Not all protein is created equal. Animal sources, like dairy, eggs, meat, and fish, tend to contain all essential amino acids in high amounts. Whey protein in particular is quickly absorbed and rich in leucine, making it ideal for post-workout recovery.
Plant-based proteins can still do the job, but they often need to be combined to ensure a full amino acid profile. For example, rice and pea protein together make a good alternative to whey. Soy protein is also a decent standalone option.
Low-quality sources, like collagen or gelatine, are missing key amino acids needed for muscle repair and shouldn’t be relied on as primary sources post-exercise.
A review in the American Journal of Clinical Nutrition (Churchward-Venne et al., 2020) found that plant proteins can stimulate muscle protein synthesis, but higher doses may be needed compared to animal-based proteins. And another study (van Vliet et al., 2015) confirmed that the amino acid profile and digestibility of the protein source matter when it comes to building muscle.
Final Thoughts
For us, this is about giving more than just exercise advice. Nutrition plays a massive role in training outcomes and protein is one of the most important variables we can influence.
By helping clients not just hit their protein goals, but time them right and choose the right types, we support faster recovery, better performance, and more meaningful progress.
So yes, protein matters. But when and how it’s consumed matters just as much.
References
Witard OC, Hearris MA, Morgan PT. (2025). Protein Nutrition for Endurance Athletes: A Metabolic Focus on Promoting Recovery and Training Adaptation. Sports Medicine. Click here to review the full research study.
Churchward-Venne TA, Pinckaers PJM, Smeets JSJ, et al. (2020). Dose-response effects of dietary protein on muscle protein synthesis during recovery from endurance exercise in young men: a double-blind randomized trial. American Journal of Clinical Nutrition, 112(2), 303–317. Click here to review the full research study.
van Vliet S, Burd NA, van Loon LJ. (2015). The skeletal muscle anabolic response to plant- versus animal-based protein consumption. Journal of Nutrition, 145(9), 1981–1991. Click here to review the full research study.
Turn Research Into Results with the Level 4 Nutrition Coach Course
If you’re working with endurance clients or those training regularly, understanding protein needs is essential – and that’s exactly what you’ll gain from our Level 4 Nutrition Coach course. A recent review in Sports Medicine (Witard et al., 2025) found that endurance athletes may need up to 2.0g of protein per kg of body mass per day during recovery or low-carb training, significantly more than the typical 1.5g many clients currently consume. The study also highlighted that a post-exercise protein dose of ~0.5g/kg is ideal for maximising muscle repair. This course guides you through research like this and translates it into practical strategies you can use with clients straight away. From fuelling long sessions to promoting adaptation and recovery. Study online, on your schedule, and become the go-to expert your clients need.
Nutrition Coach Course – Distance Study
Go Beyond Workouts! Learn to Coach Nutrition from Day One
If you’re starting a career in fitness and want to stand out as a personal trainer with specialist nutrition knowledge, the Nutrition & Exercise Specialist & Master Diplomas™ is your ideal starting point. According to a recent study published in Sports Medicine (Witard et al., 2025), athletes training with reduced carbohydrate availability may require up to 2.0g of protein per kg of body mass per day to support recovery and training adaptation — and in some cases, even 3.0g/kg during short, high-load training blocks. These are the kind of evidence-based insights you’ll explore on this course, learning how to support clients through tailored nutrition and training plans. With this qualification, you won’t just guide workouts — you’ll coach the complete picture of health, performance, and results.
Nutrition & Exercise Specialist/Master – Distance Study, In-Person & Live-Virtual
