Earlier this year, British adventurer Bear Grylls claimed that he had given up his vegan diet.
Apparently, after being an advocate of plant-based eating for years, he saw his health decline and his kidneys suffer.
In an interview with GQ Magazine in July, Grylls said: “I was a massive advocate of the vegan lifestyle for years, and wrote a book on it, but my health tanked on it. When I got COVID a couple of years ago, I doubled down on what I thought was healthy—raw juice, vegetables—and got mega-sore kidneys, almost kidney stones.
“The more research I’ve done, I’ve noticed raw vegetables are really not good for you. So I’ve started incorporating quality grass-fed steak and liver. My lunch is meat, eggs and dairy, a lot of butter, and fruit. I have liver probably every other day. I started to get strong again.”
A recent TV interview with Grylls led many papers to resurface the interview, sparking headlines that veganism “negatively” impacted his health.
So, does a vegan diet cause kidney stones? And is it preferable to include meat and dairy products for kidney health and overall health?
Let’s look at the facts.
Was Bear Grylls vegan?
When Grylls talks about the vegan book he wrote, it seems he is referring to Fuel for Life, which he co-wrote with a nutritionist. The book advocates a dairy, wheat, and sugar-free diet, but also includes recipes for meat. In the book, Grylls stated that while adopting a more plant-based diet, he still ate what he called “honest meat” (unprocessed or factory-farmed). So, was Grylls ever in fact vegan?
Given his statements, it’s likely Grylls was including plenty of animal protein in his supposed plant-based diet, which may have contributed to his “mega-sore kidneys.” However, it’s also possible other factors were behind the issue (we’ll get into this soon).
It’s not the first time a vegan diet and kidney stones has made headlines. Back in 2020, actor Liam Hemsworth blamed his plant-based diet for the condition, citing oxalates as the cause.
What are oxalates?

Oxalates are compounds in plants whose function is to bind excess calcium that the plant takes up in water through its root system. Oxalates accumulate in leaves, fruits, and seeds. When plants shed these, they get rid of excess calcium with the oxalate. However, this means that oxalates are present in some parts of plants that humans consume, such as green leafy vegetables.
In humans, oxalates have no beneficial effect; they pass through the liver and kidneys and are excreted in the urine. When oxalates combine with calcium in the urine, they form calcium oxalate crystals. The crystals may become insoluble stones depending on other factors, such as how much citrate is present. Doctors call these renal calculi or kidney stones.
Only 50 percent of the normal daily urinary oxalate excretion is from food; the rest is due to the body’s own production as part of metabolism.
Foods high in oxalates include:
- Spinach
- Green cabbage
- Beets
- Nuts
- Tea
- Rhubarb
- Chocolate
- Whole grain cereals
Research suggests getting enough calcium in the diet protects against kidney stones. However, calcium supplements may not have the same effect or may increase oxalate formation.
Meat and kidney health
A 2020 review stated that current scientific evidence agrees on the harmful effects of high meat and animal protein diets for kidney stones and the protective effect of fruits, vegetables, and vegetarian diets. The review suggests that animal protein — such as eggs, as well as poultry, fish and other meats — together with a low intake of alkaline plant foods, upsets mineral balance and is detrimental to kidney stone formers. The review also stresses the importance of adequate calcium and fluid intake.
The National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK) recommends limiting animal protein for all types of kidney stones, including calcium oxalate, calcium phosphate, and uric acid stones.

Furthermore, the National Kidney Foundation advises that eating whole grains, nuts, fruits, and vegetables is one of the most important ways to keep kidneys healthy. Additionally, they state that a plant-based diet may benefit someone with early kidney disease or prevent it from occurring in the first place.
So it’s clear that scientific evidence and expert advice does not agree with Grylls and Hemsworth. In fact, following a meat-heavy diet that Grylls promotes may be a very real risk for kidney stone formation.
Are some people more prone to kidney stones?
If diet was a factor in Grylls’ and Hemsworth’s kidney troubles, they may have been consuming too many oxalate-containing foods, such as spinach. (Hemsworth told Men’s Health that he was having five handfuls of spinach each morning in his smoothie.)
Some individuals are more susceptible to kidney stones, with studies suggesting there are environmental, dietary, hormonal, and genetic components. To date, scientists have identified 30 inherited genes that increase the risk of kidney stones.
Therefore, limiting high oxalate foods may be a sensible approach for people susceptible to kidney stones, or those who’ve had them previously.
The National Kidney Foundation advises people who form calcium oxalate stones to moderate their intake of foods such as spinach, peanuts, sweet potatoes, and rhubarb. However, it notes that cutting out oxalate foods from the diet alone is not a smart approach from an overall health perspective. Instead, they suggest eating calcium-rich foods with oxalate foods, making them more likely to bind together in the intestine before the kidneys process them.
Removing oxalates from food

Additionally, people can reduce oxalates with cooking and preparation methods. For example, a 2020 review notes that boiling spinach reduces oxalates by 87 percent, and steaming it reduces them by 42 percent. Other vegan staples such as beans and chickpeas lose significant amounts of oxalates during canning, soaking, or boiling.
The review also explains that gut health and the microbiome may also play a part in oxalate absorption and potential kidney stones. It concludes that although some people seem more prone to kidney stones, for the rest of the population, eating calcium and potassium with oxalate foods and using cooking methods to destroy oxalates significantly minimizes health risks. Furthermore, oxalate foods possess many protective, beneficial compounds that may outweigh any possible adverse effects of oxalate.
Summary
Oxalates are natural compounds found in some foods that can be reduced by soaking, canning, or cooking. Eating too many high oxalate foods may contribute to kidney stones, particularly if someone is susceptible to them because of inherited genes or other factors.
Eliminating oxalate foods from the diet is not necessary for most people and risks missing out on the beneficial nutrients that foods such as green leafy vegetables, grains, and beans contain. Instead, ensuring that the diet is sufficient in calcium is a sensible approach, as this may help the body to process oxalates safely.
Experts recommend plant-based dietary approaches for kidney health and advise against consuming too much animal protein. Therefore, a vegan diet is safe for the kidneys and may benefit overall health.
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Veganism is not just a diet, it is a way of life whereby one does not kill or harm any other creature. Bear Grylls has never practised veganism, doesn’t even know what it means to be vegan. But he will sooner or later suffer the consequences of eating meat and dairy products.
Well said.
Sounds like he’s receiving a fat check from industry! Smh
Bear Grylls was never vegan. He’s made a career out of abusing and killing animals for his fake survival TV show; that should be a clue! Eating the odd bit of tofu doesn’t make you vegan. He’s just jumped on the bandwagon of another fad, that’s all.
He claimed he was vegan, so he could claim it had damaged his health and thus promote meat and dairy, etc.
The pollution that comes from money-loving entertainment skank is never ending…
Meat eaters get kidney stone too.
I had one kidney during my veganism but I never went back to eating meat.
You were only plant based, you weren’t vegan for the animals.
My husband suffered from regular kidney stones throughout his late teens and twenties, he had a meat heavy diet and the only green thing he ate was peas, since being plant based he hasn’t had any kidney problems.
honestly , everyone s a doctor now days ! why doesn’t he just keep to himself … we are all quite happy eating veggies thank you mr Grillus –
This couldn’t possibly be Grylls jumping on the ex-vegan bandwagon could it?
Works for plenty of other click baiters.
what useful does he think he can get from the bodies and secretions of animals that he wouldn’t get from plants, can’t a human even be that stupid?
Would love to see you and Bear go head to head! I know Bear through our 30 year relationship with the most evidence based plant powders in the functional food arena!
So he was an advocate for veganism and wasn’t one himself. He lied to us.
There is a middle ground. We seem to have forgotten about Vegetarianism.
He didn’t just say that, he also stated that he would not be able to continue doing his daily pull ups and fitness regime at his now age while maintaining a vegan diet.
I’m always suspicious of someone claiming to stop being plant based for their health, it’s very unlikely – it just gets them out being criticised for just wanting to go back to meat eating
Let’s see how long it is before he has a heart attack, given the levels of saturated fat in the diet he’s described. His diet leads to health issues that cause a colossal burden on the NHS.
As a vegan that had kidney stones (wouldn´t wish them on anyone) I can only say that reducing coffee and drinking up to 3 litres of water solved the problem for me. Eat everything high in oxalates in moderation, there isn´t even a need to give up spinach or rhubarb, which are insanely hign in oxalates.
Yes, I may have eaten more oxalate rich food due to being vegan, but I also stopped jogging every morning and thought 8 cups of coffee are sufficent for my liquid intake… so never blame veganism for your health problems
Caffeine is poison for the liver. Check out Medical Medium website, books, podcasts and vids. Oxalates are never the problem.
Also the book “The Caffeine Blues” very informative
The way I read it he ate raw vegetables, since he mentioned raw juice and vegetables, or did I mis-read it all together? I can tell you that the vegan diet works. I tried every diet under the sun and none worked. I became vegan and lost 80lbs, all the indicators, blood pressure, cholesterol and the other usual suspects are all normal. I would never go back to the “regular” diet.
we should not believe for one moment that grylls’ kidney stones were caused by his vegan diet. i hope more experts come forward to dispel this misleading news. too bad we can’t analyze everything grylls put into his body to find out the real cause of his kidney stones.
“Raw vegetables were not good for me so I had to eat steak”. What happened to cooked vegetables and sensible variation?
Interesting article, thanks. Grylls blames his ‘vegan’ diet for loss of strength, which I find extremely unlikely. I’ve been vegan for 28years and get to the gym regularly 4 times a week (I started weight training at age 15) and am as fit and strong as I’ve ever been, ‘despite’ being in my mid fifties. I guess you need to know the details to understand what he was doing wrong.
Big problem with celebrity, look-at-me culture, as ever.
Why are we listening to what lowlives eat? As long as we feel good and healthy who cares what these losers eat?
Good grief, it’s amazing how many of these lightweight celebrities claim eating a vegan diet is bad for your health, then are like “so now I eat a lot of butter” 😂
This kills me! What’s the % of vegans in the world? 4%? How many meat eaters do you know who have kidney stones? I know a lot! So hardly makes sense to blame it on plant based consumers.
It is not the oxalates!! It is fat.Kidney stones are pure fat congulated. Fat,heavy metals, and toxins accumulate in the liver and other organs. Protein is also fat. Please read Anthony William the Medical medium books, vids, podcasts and website, he explains it all. I feel sorry for Bear because he will still have health issues in the long run.
Medical Medium has changed my life in amazing ways.
Kidney stones run in my family (as do migraines). My Mom & All of my siblings have had years of severely painful stones. They all eat the standard American diet. I’m vegan for 15 years & have never had a kidney stone. My genetic propensity for them was helped by my veg diet! Blaming veganism, especially after profiting from it, is disingenuous!
You know what is really stupid here? Bear says raw vegetables are unhealthy. So instead of cooking them, he packs his diet with meats, eggs, and dairy which if he was an advocate of veganism, then he would know that these are truly unhealthy.
And I wonder if when he states vegetables are unhealthy raw if he just means spinach?
It definitely sounds like he just wanted an excuse to eat more animal products.
What else is interesting is that the population is only about 4% vegan but I know a lot of people who have kidney stones and you guessed it, they aren’t vegan.
Sick of so called celebrities doing this! Has he got a new book or show coming up in the future? People can get sick with any diet, he needs to do proper research and not prove he’s a plonker by saying such sweeping statements!
I hope you do a follow up with Bear and see where his health is after abandoning his omnivore dietary practices. No one, even in the article,, mentioned what happens when your diet is too acidic (animal foods, processed foods, foods that result in a net acidic load). Consider its not all about the oxalate but the body using calcium bicarbonate, a salt, to neutralize the acidity of the body and potentially contributing to the formation of “kidney stones”, Not to mention osteopenia, especially in women. PS – My partner is a Stanford Biochemist and has advised Bear in the past about the value of a plant based diet!