What Destroys Kidney Function, and Which Kidney Myths Should You Ignore? 

What do your kidneys actually do?

Kidneys filter your blood. That is one job. They do many other jobs as well. Suboptimal kidney function can hurt your life in a lot of ways. When enough nephrons, the little working units of the kidney, are destroyed, you get diagnosed with chronic kidney disease.

What seven things destroy kidney function?

1. High blood sugar. Prediabetes, type 2 diabetes, or uncontrolled type 1 diabetes running chronically high blood sugar destroys nephrons day after day. The number one thing you can do to protect kidney function is get blood sugar back to normal. I do that with a very low carbohydrate diet that stops the blood sugar spikes, even if you have type 1 diabetes.
2. Chronically high insulin. A high carbohydrate diet, plus type 2 diabetes medicines that work by raising insulin, can leave you with hyperinsulinemia. In my view the research shows chronically high insulin also damages kidneys. Lowering carbohydrates lowers blood sugar so the pancreas does not have to dump extra insulin, and so you do not need as much injected insulin or insulin-raising pills.
3. Uncontrolled high blood pressure. In my opinion most essential hypertension is driven by chronic hyperinsulinemia that makes the body hold too much fluid. Lower carbohydrates, lower insulin, dump the unhealthy fluid, and blood pressure often comes back toward normal.
4. Daily anti-inflammatories. Over-the-counter ibuprofen or naproxen, and prescription anti-inflammatories such as Celebrex, taken every day for months or years are very hard on the kidneys. An occasional short course after a strained back or twisted ankle is how these medicines were meant to be used.
5. Tobacco in any form. Smoking, chewing, or dipping creates inflammatory molecules that wreck kidney function. Wean down and stop.
6. Daily alcohol overuse. A birthday beer once in a while is not the issue. Daily alcohol abuse harms kidney function. If you drink every day, wean down to occasional drinks only.
7. A high oxalate diet. Many vegetables are high in oxalates. Some can trigger an acute oxalate reaction if eaten raw or undercooked. The most common kidney stone in humans is the calcium oxalate stone. In my view we should focus more on lowering oxalate intake, especially after a prior stone. A stone that fully blocks the ureter can put back pressure on the kidney and destroy function over time.

Which five kidney "protections" do doctors push that I call myths?

In my opinion these five warnings either have no supporting evidence or have evidence against them.

1. "Too much animal protein harms kidneys." In my view there is not a shred of evidence that healthy animal protein from food harms kidney function, and multiple studies in healthy people do not show that higher protein intake wrecks kidneys. Highly concentrated protein shakes in huge amounts are a different story. Eating protein from animal foods the way humans have for a very long time is not the same thing.
2. "Cut saturated fat to protect your kidneys." In my view that is a fad belief. Ask your doctor, politely, to print the study that proves healthy saturated fat from animal foods or coconut oil harms kidneys, and listen for the silence.
3. "Keto or carnivore will hurt your kidneys." In my view there is not controlled research that proves this. If a doctor says that, in my opinion it shows they do not understand basic renal physiology and are buying current myths. Look for a better doctor.
4. "Limit caffeine because it harms kidneys." Doctors have tried for decades to prove caffeine is bad for the body. In my view there is zero research showing that a reasonable amount, about one to four cups of coffee a day, harms kidney function.
5. "Lower salt to protect your kidneys." Humans have sought sodium for a very long time. In my view salt your food to taste. That is not gluttony. If you already have kidney damage from past insults, still work with your own doctor, and consider the keto or carnivore approaches I teach.

Can kidney function improve on keto or carnivore?

Hundreds if not thousands of people have told us they had stage 1, 2, 3, or even stage 4 chronic kidney disease, tried keto or carnivore for 90 to 180 days, and saw kidney markers improve. That is patient report, not a guarantee. Avoid the seven destroyers above, and in my view ignore the five myths.

This is not medical advice. Work with your own doctor on labs, medications, and any change in diet, especially if you already have kidney disease.