The ketogenic diet, or keto diet for short, is a high-fat, low-carbohydrate eating plan designed to put the body into a state of ketosis. In ketosis, the body burns fat for fuel instead of carbohydrates, leading to rapid weight loss and improved metabolic health. I have had patients lose anywhere from 10-80 lbs over the course of 6 months with the keto diet.
If you have chronic kidney disease or are at risk for kidney disease, it’s key to maintain a healthy weight so I can see the allure of a keto diet. Plus, one of the best things about the keto diet is that people pay attention to what they eat, get rid of the refined carbohydrates and processed foods and sugars. I did a whole video on the keto diet a few years back but the science has changed some and let’s update it with some of the newest data.
Let’s start with polycystic kidney disease, then get into kidney stones, the keto diet vs other types of low carb diets and then figure out if any of these is right for you.
Studies have suggested that the keto diet may have potential benefits for individuals with PKD. Ketosis has been hypothesized to inhibit cyst growth in autosomal dominant polycystic kidney disease, a genetic disorder characterized by the growth of numerous cysts in the kidneys. Animal models have been extremely positive in this respect and then there was a short, small 3 month trial of humans which showed that people who did the keto diet had better kidney function over three months that was statistically significant and less cyst growth but not in a statistically significant result. There are still many questions and I’m not ready to jump on the keto bandwagon as a treatment for ADPKD, but I have my eyes, ears and mind open for more data.
Now, what if you have kidney stones like so many other Americans. Will the keto diet lead to more or will it increase your risk of stones? According to a study published in June of 2021, the answer is yes. Over a 4 year period – a really short amount of time – 7.9% of adults developed kidney stones on the keto diet. That’s significantly higher than the general population. The most common types of stones were uric acid followed by calcium based stones.
Now of course not everyone on the keto diet will develop kidney stones, and there are strategies that someone could use to lower the risk. Things like keeping extra hydrated by drinking a lot of water, making your vegetables low oxalate like cauliflower and radishes, and focusing on certain non-animal protein. So, you’re not destined to have kidney stones on the keto diet, just at a higher risk. For example a plant-based keto diet may also lower that risk.
Now what about those of you who have chronic kidney disease.
Concerns about ketogenic diets in CKD relate mainly to those keto genic diets with high protein. Now, it’s important to note that many ketogenic diets are high in fat and not that high in protein, but other times the modern day keto diet gets associated with the diets that are low carbohydrate and also high protein – like the carnivore diet. And that’s where the concern comes from. Most of the research shows that diets that are high in animal protein cause the kidneys to go into a filtering overdrive and that leads to increased pressure in the kidneys and scarring over time. Plus the keto diet, especially if high in animal protein, brings lots of fats, phosphates and makes the kidneys deal with a high acid load. All of these may worsen kidney disease and make the bodybuild up high phosphorus levels, high acid levels, and uremic toxins which can cause a lot of problems for people with kidney failure.
That’s why most dietary recommendations for protein intake stick to 0.6 grams/protein/kg of body weight. The data isn’t as clear as the theory though, especially when we look at just the keto diet. I couldn’t find any great long term data on the impact of the keto diet on kidney function and I think there are a couple of reasons for that. First of all, sustaining the keto diet over the long term can be challenging, both from a practical and health standpoint for each individual. Second of all, it’s really hard to develop long term studies that address these types of dietary issues. Very few of my patients can stay on the keto diet for the long run.
But this doesn’t necessarily mean that keto can’t be a better alternative for certain people especially if they try something called the plant-based keto diet! By shifting the focus to plant-based fats and proteins, a kidney-friendly plant based keto meal plan can support kidney health a little bit better. What’s a plant based keto diet? It’s a diet that’s low carbohydrate but high in things like avocados, nuts and seeds. You get lots of fiber and nutrients and those are the plant based foods that have lots of healthy fats to replace things like the animal proteins that you get with the typical keto diet. We know that these types of foods and plant based diets have lots of benefits for people with chronic kidney disease.
So, here’s where we stand.
First off. The diet that works is one that you can sustain for the long time. I’m not a big fan of diets like the keto diet and other diets that promote short term fixes because I think food and health should be incorporated into a lifestyle that you can sustain for a long period of time. I also know that starting a new diet can sometimes jump start people into health and, let’s face it, we are still living in a diet culture.
So, the keto diet will likely allow you to lose short term weight. It is associated with a higher risk of kidney stones so be careful if you start one. People with polycystic kidney disease may derive a benefit but the jury is still out. And, finally, the impact on people with kidney disease is still unclear as well, but we know that keto diets that are high in animal protein will put extra strain on the kidneys and may lead to progression of kidney disease.
