Protein Myths Busted: Will Eating Too Much Protein Damage My Kidneys?
Ah, the classic warning: “Don’t eat too much protein; it’ll ruin your kidneys!” If you’ve ever been told that adding an extra scoop of protein powder is a one-way ticket to kidney issues, you’re not alone. This is one of the most persistent myths in nutrition and it’s time we put it to rest.
The short answer is: no, there’s no evidence that a high-protein diet damages healthy kidneys. So unless you already have kidney disease, piling on the protein isn’t going to send you to the nephrologist.
What the Science Actually Says
The fear around protein and kidneys largely comes from a misunderstanding. Yes, high-protein intake does make your kidneys work a little harder, but this doesn’t mean damage, it’s actually part of the kidney’s adaptive response to increased protein levels. Think of it as your kidneys getting in a workout: they might grow a little stronger, but they’re not waving a white flag any time soon.
In fact, Skov et al. (1999) found that “moderate changes in dietary protein intake cause adaptive alterations in renal size and function without indications of adverse effects.” Translation? Your kidneys adapt to the extra protein just fine without any harm. They grow a bit larger, process the protein, and get right back to business as usual.
So How Much Protein Is “Too Much”?
The limits are higher than most people think. For example, Poortmans and Dellalieux (2000) reported that protein intakes up to 2.8 grams per kilogram of body weight per day had no negative effect on kidney function in well-trained athletes. That’s around 200 grams of protein daily for someone who weighs 72kg a level most people never even come close to hitting.
Even in more extreme cases, such as bodybuilders on high-protein diets for extended periods, there’s no evidence of kidney damage. Antonio et al. (2016) looked at resistance-trained men consuming between 2.51 and 3.32 grams of protein per kilogram daily for a full year and found no harmful effects on liver, kidney function, or blood lipids. In other words, even at levels higher than most people could stomach (literally), kidneys were still running just fine.
Kidney Disease vs. Healthy Kidneys
Now, there’s one caveat. If someone already has compromised kidney function or kidney disease, then a high-protein diet may exacerbate the problem. In those cases, kidney function is already limited, and additional strain could indeed worsen the situation. But for healthy individuals, this simply doesn’t apply.
Busted: Protein and Kidneys Can Coexist Peacefully
If you’re healthy, there’s no reason to fear that extra serving of chicken breast or shake. Your kidneys are equipped to handle a high-protein diet without issue. So unless your doctor has told you otherwise, you can enjoy that steak without mentally counting the grams.
The Bottom Line
There’s zero evidence that high-protein diets harm healthy kidneys. So, next time someone warns you that your protein shake is “too much,” feel free to smile and tell them the science says otherwise.
References:
Skov, A. R., et al. (1999). "Changes in renal function during weight loss induced by high vs low-protein low-fat diets in overweight subjects." International Journal of Obesity, 23(11), 1170-1177.
Poortmans, J. R., & Dellalieux, O. (2000). "Do regular high-protein diets have potential health risks on kidney function in athletes?" International Journal of Sport Nutrition and Exercise Metabolism, 10(1), 28-38.
Antonio, J., et al. (2016). "A high protein diet has no harmful effects: a one-year crossover study in resistance-trained males." Journal of Nutrition and Metabolism, 2016.
