If you're managing kidney stones or following a low-oxalate diet, knowing which foods to avoid is just as important as knowing what's safe. But the highest-oxalate foods aren't always obvious — some are marketed as health foods, while others hide in plain sight.
If you're managing kidney stones or following a low-oxalate diet, knowing which foods to avoid is just as important as knowing what's safe.
This guide covers the most significant dietary sources of oxalate, organized by food group, with actual measured values from research. The goal isn't to eliminate all these foods forever — it's to give you awareness so you can make informed choices about your oxalate budget.
What Makes a Food "High Oxalate"?
There's no universal standard, but most registered dietitians and urologists use this classification:
- Very High: 300+ mg oxalate per serving
- High: 100-300 mg per serving
- Moderate: 25-100 mg per serving
- Low: <25 mg per serving
For context, people on a strict low-oxalate diet aim for under 40-50 mg per day total. A single serving of a very-high-oxalate food can exceed an entire week's allowance.
The Leafy Green Offenders
Leafy greens are nutritional powerhouses for most people — but for kidney stone formers, several varieties are oxalate disasters.
Spinach — The #1 Offender
Oxalate content: 750+ mg per cup (cooked), 140+ mg per cup (raw)
Spinach contains more oxalate than almost any other commonly eaten food. A single cup of cooked spinach delivers more than two weeks' worth of oxalate for someone on a strict diet. Raw spinach salads, spinach smoothies, and spinach omelets are all extremely high-oxalate meals.
Smart swap: Romaine lettuce, iceberg lettuce, or cabbage (<10 mg per cup)
Swiss Chard
Oxalate content: 600-900 mg per cup (cooked)
Often recommended as a spinach alternative, Swiss chard is actually just as problematic. Avoid it entirely if you're managing kidney stones.
Smart swap: Kale (60% less oxalate) or broccoli
Beet Greens
Oxalate content: 900+ mg per cup (cooked)
Even higher than spinach. The greens from beets are often discarded, but if you eat them (in salads or sauteed), they're one of the highest-oxalate foods known.
Root Vegetables and Tubers
Beets
Oxalate content: 100-675 mg per 100g (varies by preparation and variety)
Beets themselves (not just the greens) are very high in oxalate. Roasted beet salads, beet smoothies, and beet juice are all problematic. Even pickled beets retain significant oxalate.
Smart swap: Radishes or jicama for salads; carrots for roasting (much lower oxalate)
Sweet Potatoes
Oxalate content: 140+ mg per medium sweet potato (with skin)
Sweet potatoes are trendy and nutritious, but they're surprisingly high in oxalate. Sweet potato fries, baked sweet potatoes, and sweet potato casseroles all deliver significant oxalate.
Smart swap: White potatoes (30-50 mg if peeled) or mashed cauliflower
Rhubarb
Oxalate content: 800-1,000+ mg per cup
Rhubarb is among the absolute highest-oxalate foods. Even small amounts in pies, compotes, or jams contribute enormous oxalate loads. There's no good substitute — simply avoid it.
Rhubarb is among the absolute highest-oxalate foods.
Nuts and Seeds
Almonds
Oxalate content: 122 mg per ounce (about 23 almonds)
Almonds are the highest-oxalate nut. Almond milk, almond butter, almond flour, and whole almonds all contribute significant oxalate. Just 1/4 cup of almonds exceeds many people's daily oxalate budget.
Smart swap: Cashews (~35 mg per ounce) or macadamia nuts (~12 mg per ounce)
Peanuts
Oxalate content: 80-100 mg per ounce
Peanuts and peanut butter are moderate-to-high in oxalate. Small portions (1-2 tablespoons peanut butter) may be acceptable, but large amounts add up quickly.
Chia Seeds
Oxalate content: 140+ mg per ounce (2 tablespoons)
Chia seeds are marketed as a superfood and commonly added to smoothies, yogurt, and overnight oats. They're very high in oxalate. Skip them entirely.
Sesame Seeds / Tahini
Oxalate content: 140+ mg per ounce of seeds; tahini similar
Sesame seeds and tahini (ground sesame paste, common in hummus and Middle Eastern dishes) are very high in oxalate.
Smart swap: Sunflower seed butter (lower oxalate)
Soy Products
Tofu
Oxalate content: 80-150 mg per 100g (varies by firmness and processing)
Tofu is a staple protein for vegetarians and vegans, but it's high in oxalate. Stir-fries, tofu scrambles, and tofu bowls all contribute significant oxalate.
Smart swap: Eggs, chicken, fish, or dairy (all zero oxalate)
Soy Milk
Oxalate content: 20-40 mg per cup
Lower than tofu but still moderate. If you drink multiple glasses per day, it adds up.
Smart swap: Cow's milk (zero oxalate, plus calcium) or rice milk
Chocolate and Cocoa
Cocoa Powder / Dark Chocolate
Oxalate content: 600+ mg per 100g cocoa powder; dark chocolate 100-200+ mg per ounce
Chocolate is one of the absolute highest-oxalate foods. Hot chocolate, chocolate smoothies, chocolate desserts, and even dark chocolate bars (marketed as healthy) are extremely high. Milk chocolate is somewhat lower but still significant.
Smart swap: Vanilla desserts, caramel, butterscotch, or white chocolate (contains no cocoa)
Beverages
Black Tea
Oxalate content: 40-100+ mg per cup (varies by brew strength and type)
Black tea is a sneaky source of dietary oxalate, especially for people who drink multiple cups per day. Iced tea is particularly concentrated.
Smart swap: Herbal teas (chamomile, peppermint, rooibos), coffee (<5 mg per cup)
Spinach or Beet Smoothies
Oxalate content: 200-500+ mg per smoothie
The typical "green smoothie" with spinach, almond milk, chia seeds, and berries can deliver 300-500 mg of oxalate in a single glass — more than a week's worth for someone on a strict diet.
Smart swap: Banana-blueberry smoothie with cow's milk (see our smoothie recipes guide)
Grains
Whole Wheat Products
Oxalate content: 20-30 mg per slice of whole wheat bread; whole wheat pasta similar
Whole wheat bread, pasta, and flour are moderate in oxalate. While not as high as spinach or almonds, they add up if you eat them multiple times per day.
Smart swap: White bread, white pasta, white rice (all <5 mg per serving)
Oatmeal
Oxalate content: 30-50 mg per cup (cooked)
Oatmeal is a breakfast staple but contributes moderate oxalate. Instant oats and steel-cut oats are similar.
Smart swap: White rice porridge, cream of wheat (lower oxalate)
Fruits
Star Fruit
Oxalate content: 200+ mg per fruit
Star fruit is extremely high in oxalate and also contains caramboxin, a neurotoxin dangerous for people with kidney disease. Avoid entirely.
Raspberries
Oxalate content: 48 mg per cup
Raspberries are the highest-oxalate common berry. Blackberries are similar (~44 mg per cup).
Smart swap: Blueberries (~4 mg per cup), strawberries (~15 mg per cup)
Kiwi
Oxalate content: 20-25 mg per fruit
Moderate oxalate. One kiwi is fine, but eating multiple per day adds up.
Smart swap: Grapes, melon, or bananas
Legumes
Navy Beans
Oxalate content: 75+ mg per cup (cooked)
Navy beans are the highest-oxalate bean variety. Other beans vary but are generally moderate (20-50 mg per cup).
Smart swap: Pinto beans or black beans (lower oxalate), or animal proteins
How Cooking Affects Oxalate Content
Here's one piece of good news: boiling vegetables can reduce oxalate content by 30-87%, depending on the food. Oxalate leaches into the cooking water, which you then discard.
Here's one piece of good news: boiling vegetables can reduce oxalate content by 30-87%, depending on the food.
For example, boiling spinach removes significant oxalate compared to eating it raw (though it's still very high either way). Steaming is less effective than boiling.
Learn more in our cooking methods guide.
The 80/20 Rule: Focus on the Biggest Contributors
You don't need to track every milligram of oxalate. For most people, simply avoiding the very-high-oxalate foods listed above eliminates 80% of dietary oxalate:
- Spinach
- Rhubarb
- Beets (and beet greens)
- Swiss chard
- Almonds
- Chocolate
- Soy products
If you cut these foods, you've done the heavy lifting. The rest is fine-tuning.
This Isn't About Elimination — It's About Awareness
The goal of a low-oxalate diet isn't to achieve zero oxalate intake. That's unnecessary and nearly impossible. The goal is to stay within your personal oxalate budget (typically 40-100 mg/day) while eating a varied, nutritious diet.
Some people can tolerate moderate amounts of high-oxalate foods when paired with calcium. Others need stricter limits. Work with a urologist or registered dietitian to find your individual threshold.
Tools to Help You Succeed
- Browse high-oxalate foods — Full database sorted by oxalate content
- Food swaps guide — Lower-oxalate alternatives for every high-oxalate food
- Cooking methods guide — Reduce oxalate through food preparation
- Restaurant guides — Navigate menus when dining out
Understanding which foods are highest in oxalate is the first step toward better kidney health. Armed with this knowledge, you can make confident choices that reduce your stone risk without sacrificing enjoyment of food.