As certified sports dietitian who also trains and competes in Brazilian jiu-jitsu internationally, protein is something I talk about every single day – with clients in clinic or with training partners on the mats. And I can tell you: no nutrient gets more opinions or nonsense thrown at it.
Some of the myths are harmless, but others are actively holding people back. I see athletes under-eating or hyper focussing on protein, women skipping meals and healthy adults scared of kidney damage. So let’s clear the air. Here are the six protein myths I find myself debunking most often, and what the evidence (and a decade of working with clients) actually says.
Myth 1: More protein always means more muscle
If this were true, every person drinking four protein shakes a day would look like an Olympic weightlifter. The research is pretty settled: muscle protein synthesis maxes out at roughly 1.6 to 2.2 grams per kilogram of body weight per day for most athletes. Beyond that, you’re not building extra muscle, you’re just producing very expensive urine.
What actually matters far more than total grams is distribution. Your body can only use roughly 25–40 g of protein per meal to drive muscle protein synthesis. So four meals of 30 g will do more for you, than two meals of 60 g, even though the totals are the same. This is something I emphasise with my active clients – especially the ones trying to gain mass while training six days a week.
Myth 2: You must consume protein 30 minutes post training
The so-called “anabolic window” is one of the most stubborn myths in fitness. The truth: the window is more like several hours, not 30 minutes. If you’ve eaten a proper meal with protein in the few hours before training, you’ve already got amino acids circulating. You don’t need to sprint to your shaker the second class or your session ends.
That said, I do recommend a protein-containing meal within 1–2 hours post-training, especially after hard sparring or a lifting session. Not because the window is closing, but because it’s a convenient way to hit your daily protein target and it supports recovery. The obsession with timing is misplaced; total daily intake and spreading it across meals matters far more.
Myth 3: Plant protein is inferior
This one has more nuance than either side will admit. Most plant proteins are lower in one or two essential amino acids (usually leucine or lysine), and they’re digested slightly less efficiently than animal protein. That’s true. What’s also true is that it doesn’t matter nearly as much as the internet has told you it does.
If you eat a varied diet – legumes, grains, nuts, seeds, soy – you cover every amino acid you need, without obsessing over “complete proteins” at every meal. And plant-forward eaters tend to get more fiber, more polyphenols and better cardiovascular markers. The fix for plant protein isn’t to abandon it; it’s to eat slightly more of it (aim ~10–15% higher total intake) and include a leucine-rich source like soy or a pea-protein shake around training.
Myth 4: High-protein diets damage your kidneys
This one genuinely frustrates me, because it stops people – especially women and older adults – from eating enough protein. The studies this claim is based on, were done in people with pre-existing kidney disease. In healthy adults, high protein intake (up to 3+ g/kg in some studies) has not been shown to cause kidney damage. A 2018 meta-analysis in the Journal of Nutrition pooled 28 trials in healthy adults and found no difference in kidney function between higher- and lower-protein diets.
If you have diagnosed kidney disease, yes, you need to work with a dietitian (me!) to manage your protein. If you don’t, eating 1.6–2.2 g/kg to support training is completely safe. Stay hydrated, eat a varied diet, and stop worrying.
Myth 5: Women don’t need as much protein as men
Women need the same amount of protein per kilogram of body weight as men do. The only reason the absolute number tends to be lower is because women, on average, weigh les. It’s not because female physiology somehow needs less of an essential nutrient.
If anything, female athletes often need to be more intentional about protein, because they’re more likely to be under-eating overall. If you train hard – BJJ, running, CrossFit, whatever – aim for 1.6–2.2 g/kg. For a 65 kg woman that’s 104–143 g per day, spread across 4 meals. Most of the women I see in clinic are eating half that and then wondering why recovery feels brutal.
Myth 6: Protein is the most important nutrient for building muscle
Protein is the raw material for muscle and therefore very necessary, but nowhere near sufficient on its own. If you’re under-eating calories, your body burns through protein as fuel before it ever reaches muscle repair. If carbs are too low, training intensity drops and you lose the overload signal that tells muscles to grow. And bad sleep tanks muscle protein synthesis no matter how many grams of chicken you eat.
Carbs also help your body use the protein you eat: they spike insulin, which is strongly anti-catabolic and shuttles amino acids into muscle cells. A chicken breast alone is fine. A chicken breast with rice is working harder for you. This is why I push back when clients tell me they’re “cutting carbs” while trying to build muscle — they’re making their own protein less effective. Protein is a lever. It’s not the lever. Muscle growth needs the full picture: progressive training, enough energy, carbs around sessions, quality sleep, and then enough protein to rebuild.
The bottom line
Protein is important, but the rules around it are simpler than the industry wants you to believe:
- Aim for 1.6–2.2 g/kg body weight per day if you train
- Spread it across 3–4 meals of 25–40 g each
- Don’t stress the post-workout window
- Plant protein works, just eat a bit more of it
- Your kidneys are fine
- Women, eat more. Seriously.
- Protein alone won’t build muscle: you also need enough calories, combine carbs with proteins and good sleep
If you want help figuring out exactly what your intake should look like for your sport, your goals, or your stage of life, Get in touch or have a look at my nutrition services.