The Truth About Kidney Stone Friendly Diets with Dr. Robert Chan

Staring longingly at temptation, this pug mirrors the struggle of sticking to a kidney stone-friendly diet while eyeing a delectable pastry.

From a recent interview I did with the Worst Pain Ever Kidney Stone community, the internet's largest collection of kidney stone sufferers.

If you’ve had a kidney stone, chances are you’ve been told to “watch your diet.” But what does that really mean – and what should you be looking out for? To make sense of it all, we spoke with Dr. Robert Chan, a board-certified urologist, to get his insights on stone-friendly diets and what it takes to build habits that last.

I’ve heard genetics can play a big role in stone formation. Does what we eat really matter when it comes to forming or preventing kidney stones?

This is the age-old question of nature versus nurture – genetics versus diet. Some people are born with conditions like primary hyperoxaluria or cystinuria, which raise their risk of forming kidney stones. Researchers have even identified specific inherited genes linked to stone formation¹.

While we can’t really choose who are parents are and the genes we’re born with, we can choose what we eat. It does matter. One study showed that calcium oxalate stone formers who followed a diet high in calcium but low in animal protein and sodium showed a 51% reduction in stone recurrence2. That’s a powerful reminder that your diet choices really can make a difference!

What’s the most common misconception about kidney stone diets that isn’t true?

Almost 80% of kidney stones are made up of calcium oxalate, which leads many stone formers to believe they need to cut out calcium in their diet. As a result, they stop drinking milk, avoid cheese and yogurt, and throw out calcium-rich vegetables like kale. Unfortunately, this can actually increase their chance of getting another kidney stone! 

The truth is calcium plays a protective role against calcium oxalate stones. It binds to oxalate in the gut, preventing oxalate from being absorbed into the bloodstream and later passed into the urine. Without enough calcium, more oxalate ends up in your urine, and that can raise your risks of forming new stones3.

What are the most common challenges that you see among your patients? Why do these happen and any advice there?

Many patients believe that they have to be perfect with their diet, which often leads to an “all-or-nothing” mindset. When they slip up – maybe by eating too much chocolate or one too many almonds – they don’t just feel discouraged. They feel like they’ve failed completely, and give up on the diet altogether.

That’s why I always remind my patients to strive for consistency over perfection. It’s much more important to stick with a sustainable diet that works, rather than one that is “perfect” for preventing stones. Much like working out, the best exercise is one you’re actually willing to stick with.

Many stone formers worry they’ll need to follow a strict diet forever. How do you help them understand what the journey really looks like?

My patients often despair when they’re handed a long list of high-oxalate foods. They feel like everything they enjoy is suddenly off-limits, and there is nothing left to eat! 

That’s why it’s important to focus on what really matters. In most cases, you only need to cut out foods which are very high in oxalates such as spinach, Swiss chard, and almond products. Otherwise, it’s all about moderation. You can still have foods that contain some oxalate, like chocolate, tea, and nuts. Just enjoy them occasionally and in smaller portions. 

One tip I often share with my patients is to find stone-friendly alternatives for the foods they do need to cut out. For example, try swapping spinach with broccoli or kale. Try sweet potatoes instead of baked potatoes. Rather than almonds, snack on handful of sunflower seeds instead. Finding simple food swaps like these can make the diet more manageable.

What are other essential tips for managing diet and staying stone-free?

1. Celebrate other health wins

A stone-friendly diet provides many other benefits, like weight loss and better heart health. It encourages you to cut down on low sodium and processed sugars, as well as practice moderation. It’s normal for motivation to fade as time passes after a painful stone episode, but the added health benefits can be good motivators to stay on track. 

2. Track what you eat

If you have to focus on just one thing: log and keep track what you’re putting in your body every day. Keeping a record of helps you stay within your limits and spot patterns that could be increasing your risks. Whether it’s using a mobile app like StoneFree AI (stonefreeai.com) or just jotting things down in a notebook, the key is to start – and stick with it.

This interview has been edited for length and clarity.  

References:

1. Geraghty, R., Lovegrove, C., Howles, S., & Sayer, J. A. (2024). Role of Genetic Testing in Kidney Stone Disease: A Narrative review. Current Urology Reports, 25(12), 311–323. https://doi.org/10.1007/s11934-024-01225-5

2. Borghi, L., Schianchi, T., Meschi, T., Guerra, A., Allegri, F., Maggiore, U., & Novarini, A. (2002). Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria. New England Journal of Medicine, 346(2), 77–84. https://doi.org/10.1056/nejmoa010369

3. Holmes, R. P., Knight, J., & Assimos, D. G. (2015). Lowering urinary oxalate excretion to decrease calcium oxalate stone disease. Urolithiasis, 44(1), 27–32. https://doi.org/10.1007/s00240-015-0839-4