Zucchini, yellow squash, and other summer varieties are the lowest-potassium squash options, coming in around 162 mg per half-cup cooked serving. That falls well under the 200 mg threshold that renal dietitians use to classify a food as “low potassium.” Winter squash varieties like acorn and butternut run significantly higher.
The 200 mg Threshold
Foods with less than 200 mg of potassium per serving are considered lower-potassium choices, while anything above that line counts as higher-potassium. This cutoff, used by hospital nutrition programs including Northwestern Medicine, is the standard benchmark for people managing their potassium intake. Most summer squash falls comfortably below it, while most winter squash does not.
Summer Squash: Your Best Options
Summer squash is the category to focus on. According to the National Kidney Foundation, zucchini and yellow squash contain about 162 mg of potassium per half-cup cooked serving. That’s a meaningful amount below the 200 mg cutoff, giving you some flexibility in how you build the rest of your meal.
The broader summer squash family includes several other varieties worth knowing about. Pattypan, scallopini, and globe squash all fall into a similar range. DaVita, which specializes in kidney care nutrition, reports that summer squash varieties generally contain between 90 and 250 mg of potassium per half-cup cooked, with most landing in the lower end of that range. Yellow crookneck squash tracks closely with standard yellow squash at around 162 mg.
Chayote is another solid pick. A full cup of raw chayote contains about 165 mg of potassium, which is notable because that’s a larger portion size than the half-cup measurement used for other squash. Cup for cup, chayote is one of the most potassium-friendly squash options available.
Spaghetti Squash: A Borderline Choice
Spaghetti squash sits in an interesting middle ground. One cup of cooked spaghetti squash contains about 181 mg of potassium, which technically keeps it under the 200 mg line. But that number is close enough to the cutoff that portion size matters. If you’re eating a generous serving, you could easily push past it. Spaghetti squash works on a potassium-restricted diet, but it requires a bit more attention to how much you put on your plate compared to zucchini or yellow squash.
Winter Squash: The Higher-Potassium Group
Winter squash varieties are where potassium levels climb sharply. Acorn, butternut, and hubbard squash are all denser and starchier than their summer counterparts, and that density comes with significantly more potassium per serving. These varieties can easily exceed 300 to 400 mg per half-cup cooked, placing them firmly in the higher-potassium category. If you’re actively limiting potassium, winter squash should be an occasional choice rather than a regular one, and portion control becomes essential.
Serving Size and Preparation Matter
The numbers above are based on half-cup cooked servings for most varieties, which is smaller than what many people actually eat in a sitting. A plate of roasted zucchini at dinner could easily be a full cup or more, which would roughly double the potassium you’re taking in. Keeping your portions close to that half-cup benchmark is the simplest way to stay within a comfortable range.
Boiling is sometimes recommended as a way to leach potassium out of vegetables, and it does work for many foods like potatoes and leafy greens. However, research published in the journal Toxins found that boiling did not significantly reduce potassium in zucchini. The good news is that zucchini is already low enough that leaching isn’t necessary. For winter squash, where potassium is higher, boiling in plenty of water and draining may help reduce the total somewhat, though the effect varies.
One thing to watch out for is canned squash. Canned zucchini Italian-style contains around 622 mg of potassium per cup, compared to about 475 mg for a cup of plain boiled zucchini. The added ingredients in canned preparations, including sauces and seasonings, can dramatically increase the potassium content. Fresh or frozen summer squash prepared simply at home is the most reliable way to keep potassium in check.
Quick Comparison by Variety
- Zucchini: ~162 mg per 1/2 cup cooked
- Yellow squash: ~162 mg per 1/2 cup cooked
- Chayote: ~165 mg per 1 cup raw
- Pattypan/scallopini: 90–250 mg per 1/2 cup cooked (most on the lower end)
- Spaghetti squash: ~181 mg per 1 cup cooked
- Acorn, butternut, hubbard: 300+ mg per 1/2 cup cooked
If you’re building meals around squash on a potassium-restricted diet, summer varieties give you the most freedom. Zucchini, yellow squash, and chayote are all reliably under the 200 mg line at standard serving sizes, and they’re versatile enough to grill, sauté, spiralize, or add to soups without worrying about your totals creeping up.