Whether it’s a new gym-goer wondering if they need a shake straight after training, or a regular client asking if they’re eating too much chicken, protein always finds its way into the conversation. We’re no strangers to the debate either. What kind? How much? When?
We’ve tackled some of these questions before. In our Protein and Timing article, we looked at whether the famous ‘anabolic window’ really matters. Then in Which Protein Is Better?, we compared the different types of protein and their uses. And in Protein Requirements for Women in Strength Training, we explored how protein needs can change depending on the individual.
Despite all that, protein remains one of the most frequently asked-about topics in our Nutrition Coach and Personal Trainer courses. It’s clear that people want clarity, not just theory. So in this article, we’re going back to basics, looking at the latest research, busting a few assumptions, and helping you figure out what your clients really need.
Why Protein Matters
Protein is one of the three macronutrients we literally can’t do without, the other two being fat and carbohydrate. It’s not just for muscle building. Protein is essential for hormone production, immune function, tissue repair, enzymes, neurotransmitters, and even hair and skin. Your body uses it constantly, so if you don’t get enough through your diet, it starts breaking down its own tissue to compensate.
A well-cited study by Wolfe (2017) put it plainly: dietary protein is vital to preserving muscle mass, promoting recovery from training and even supporting metabolic health, particularly as we age or when we’re trying to manage body composition. That’s not to mention its impact on satiety and appetite control; big wins for clients with weight management goals.
So How Much Do We Need?
That depends on who you are and what you do.
The general recommendation for sedentary adults is 0.8g of protein per kilogram of body weight per day. But here’s the thing, that’s just the minimum to avoid deficiency, not the ideal amount for health, fitness or recovery.
As a rough guide:
- Sedentary adults: 0.8 g/kg body weight/day
- Active individuals: 1.2–1.6 g/kg body weight/day
- Strength or endurance athletes: 1.6–2.2 g/kg body weight/day
These figures are backed by meta-analyses such as Morton et al. (2018), which reviewed 49 studies on resistance training and protein intake, and Cermak et al. (2012), which examined 22 trials, both showing that higher protein intake supports significant gains in muscle mass and strength, who found that protein supplementation around these higher ranges significantly supports muscle mass and strength gains during training.
Different Goals, Different Needs
However, not all activities place the same demands on the body. That’s why protein needs should reflect what someone actually does with their body.
- Strength training: Clients lifting weights or doing resistance work regularly will need more protein to support muscle repair and growth. The higher end of 1.6–2.2 g/kg is ideal.
- Endurance athletes: While carbs are still king for fuelling long-distance efforts, endurance athletes still benefit from 1.2–1.6 g/kg to support repair and reduce muscle breakdown.
- Older adults: Ageing can increase protein needs because of anabolic resistance. Essentially, the body becomes less efficient at using protein. Recommendations often go up to 1.2–1.5 g/kg for this group.
- Weight loss clients: A higher protein intake (around 1.6 g/kg or more) can help with satiety, preserving lean mass, and metabolic rate during a calorie deficit.
The point is, context matters. And that leads us into a study that might surprise you.
More Protein Isn’t Always Better: A Pilates-Based Study
It’s easy to assume that more protein equals better results, no matter the training style. But a 2025 study by Karpouzi et al. tested this assumption and found that things aren’t so straightforward.
In their randomised, quadruple-blind trial, the researchers looked at trained women doing Pilates twice a week for 10 weeks. One group supplemented daily with whey protein (0.6 g/kg bodyweight), the other took a carbohydrate placebo (maltodextrin). The participants already had a fairly high protein intake from food, about 1.3 g/kg/day.
What Were They Looking At?
They wanted to see if the protein supplement would improve outcomes compared to placebo in three areas:
- Body composition
- Core muscle endurance
- Joint flexibility
How Was It Done?
The women trained using Reformer and Cadillac Pilates apparatus in instructor-led classes. Their strength, flexibility, and body composition were tested at the start and after 10 weeks. Body composition was measured using both DXA and BIA, and muscle endurance was assessed using McGill’s core test battery. Flexibility was measured with the sit-and-reach test.
What Did They Find?
After ten weeks of Pilates training, both groups, whether they were taking protein supplements or the carbohydrate placebo, showed noticeable improvements across the board. Core muscle endurance went up significantly, with trunk flexor, lateral, and extensor endurance increasing by an average of 23% to 48%. Flexibility also improved, as seen in the sit-and-reach test, and there were modest but meaningful changes in body composition, such as reductions in body fat and increases in lean mass or limb-specific muscle mass.
What surprised the researchers, and might surprise you too, was that the group taking additional protein didn’t perform any better than the placebo group. Despite having a higher daily protein intake overall, there were no extra gains in strength, flexibility, or body composition. The authors concluded that for this group of already trained women, who were already consuming about 1.3 g/kg of protein per day through food, extra supplementation wasn’t necessary.
Key Takeaways
This study challenges the common assumption that more protein always equals better results. It highlights how protein needs aren’t just about training more or pushing harder in the gym. Instead, what matters is the full context; what kind of training is being done, how intense it is, what the rest of the diet looks like, and what the individual’s goals and training history are.
Someone new to training might respond well to higher protein intake, especially if they’re building habits and recovering from unfamiliar movements. But someone who’s been doing Pilates regularly and already eats well might not see any further benefit from supplements. This study reminds us that protein advice needs to be individualised, not just copied and pasted across all clients.
Final Thoughts
There’s no one-size-fits-all answer when it comes to protein. While it’s a cornerstone of good nutrition, the right amount and whether to supplement depends entirely on the person, their habits, their goals, and what type of training they do.
It’s our job to ask the right questions, assess each client individually and stay up to date with the research. It’s tempting to fall back on general advice or trends, but it’s far more valuable to treat every client’s needs as unique.
So next time the protein question comes up, remember this, context is everything.
References
- Wolfe RR. Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? J Int Soc Sports Nutr. 2017;14:30. Click here to review the full research article.
- Morton RW et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376–384. Click here to review the full research article.
- Cermak NM et al. Protein supplementation augments the adaptive response of skeletal muscle to resistance-type exercise training: a meta-analysis. Am J Clin Nutr. 2012;96(6):1454–1464. Click here to review the full research article.
- Karpouzi C, Kypraiou A, Mougios V, Petridou A. Effects of protein supplementation during Pilates training on body composition, core muscle endurance, and joint flexibility in trained women: a randomised controlled trial. J Int Soc Sports Nutr. 2025;22(1):2472891. Click here to review the full research article.
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