The Effects of High-Protein Diets on Kidney Health and Longevity, Journal of the American Society of Nephology, July 2020

Although high-protein diets continue to be popular for weight loss and type 2 diabetes, evidence suggests that worsening renal function may occur in individuals with—and perhaps without—impaired kidney function.

High dietary protein intake can cause intraglomerular hypertension, which may result in kidney hyperfiltration, glomerular injury, and proteinuria.

It is possible that long-term high protein intake may lead to de novo CKD [chronic kidney disease].

The quality of dietary protein may also play a role in kidney health. Compared with protein from plant sources, animal protein has been associated with an increased risk of ESKD [end-stage kidney disease] in several observational studies, including the Singapore Chinese Health Study. Potential mediators of kidney damage from animal protein include dietary acid load, phosphate content, gut microbiome dysbiosis, and resultant inflammation.

People with diabetes often have reduced kidney function, even before it’s diagnosed. High blood glucose damages small blood vessels in the kidney. High blood glucose also causes high blood pressure (by reducing nitric oxide) which also damages blood vessels. And then … there are literally millions of people walking around with prediabetes (or undiagnosed diabetes) who aren’t aware that they’re experiencing high blood glucose, and for whom high-protein diets would not be advised.

Also, as stated here, even people without impaired kidney function may experience worse renal function when they eat a high-protein diet.

Animal food has a lot of protein. If it’s protein you’re after, it fits the bill, but it does not come without risks. Worsening kidney function is one.