Will a High-Protein Diet Damage Your Kidneys?

The easy stuff

  • If you already have kidney problems, you should eat less protein. The more protein you eat, the harder your kidneys have to work. If your kidneys are already struggling, don’t make them work harder than they have to.

  • If you’re eating less than 1.5g/kg/day of protein, then two large meta-analyses say you’re fine. To put that in perspective, if you weigh 80kg (or 176 pounds) then you can eat 120g of protein (over 1.5 pounds of 80% ground beef)!

So why do people think a high-protein diet causes kidney damage?

  • A couple rat studies found kidney damage when the rats consumed high amounts of protein.

  • One the other hand, other rat studies found no evidence of kidney damage.

But what if I want to eat even more protein?

I’ve found only one study that addresses very high protein consumption among humans.

It lasted for one year, and followed athletes alternating between two diets (switching every 2-4 months):

  • ~30kcal/kg/day and ~2.5g/kg/day of protein.
  • ~34kcal/kg/day and ~3.32g/kg/day of protein.

Their average weight was 84kg (185 pounds), so they were eating roughly:

  • 2520 calories and 210g of protein.
  • 2856 calories and 279g of protein.

You’d have to eat over 3 pounds of 80% ground beef to get to 279g of protein (that would be over 3000 calories of beef)! Unless you’re chugging protein shakes or eating tons of lean meat, you won’t be eating as much protein as those guys.

And how did they fair? Zero negative side effects, kidneys or otherwise.

To be clear, the study only lasted one year and didn’t measure long-term effects.

At the End of the Day

If you stick to a standard carnivore diet it’s unlikely you’ll get above the well-studied 1.5g/kg/day range, especially if you’re picking fattier cuts to stay in ketosis.

So what do you think? How much protein will you eat?

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