Bok choy is low FODMAP at a standard serving of 75 grams (about 2.65 ounces), which is roughly one cup of raw chopped leaves and stems. That makes it one of the safest vegetable choices during the elimination phase of a low FODMAP diet. Once you go above 100 grams, though, sorbitol levels start to climb into moderate territory, so portion size matters.
Safe Serving Sizes
Monash University, the research group that developed the FODMAP diet and maintains the most widely used food database, lists bok choy as green light (low FODMAP) at 75 grams per sitting. At 100 grams or more, bok choy contains a moderate amount of sorbitol, a sugar alcohol that can trigger bloating, gas, and diarrhea in sensitive individuals. So you have a comfortable window, but doubling your portion could push you into symptom territory.
For reference, 75 grams is about one cup of raw bok choy or a single small head. If you’re cooking it down in a stir-fry, keep in mind that bok choy shrinks significantly with heat, so what looks like a small amount on your plate may have started as a larger raw volume. Weighing it before cooking gives you the most reliable measure.
Monash completed a full review of its vegetable category in July 2024, adding missing serving size details and updating how fructose-containing vegetables are rated. Bok choy’s classification remained stable through that update, so the 75-gram threshold reflects current testing.
How Bok Choy Compares to Other Cabbages
Not all cabbages behave the same way on a low FODMAP diet, and the differences are significant enough to change what you put in your cart. Red and white cabbage share bok choy’s green light status at a standard 75-gram serve. Chinese cabbage (sometimes labeled Napa cabbage) is even more generous: it doesn’t reach moderate fructan levels until portions hit 500 grams, making it one of the most FODMAP-friendly vegetables available. Savoy cabbage, on the other hand, is much more restrictive. Its safe serving tops out at just 40 grams, with fructan levels rising to moderate at 55 grams.
If you’re building an Asian-inspired meal and want to maximize your vegetable volume without stacking FODMAPs, Napa cabbage gives you the most room. Bok choy sits comfortably in the middle, offering a safe and flavorful option as long as you stay near that 75-gram mark.
Why the Specific FODMAP in Bok Choy Matters
The FODMAP that limits bok choy is sorbitol, not fructans or fructose. This distinction is useful during the reintroduction phase of the diet. If you’ve already tested sorbitol (common sources include stone fruits like peaches and plums) and found you tolerate it well, you may be able to eat bok choy in larger portions without problems. If sorbitol is one of your personal triggers, sticking closer to 75 grams keeps you in safe territory.
FODMAP stacking also applies here. If you’re eating bok choy alongside other sorbitol-containing foods in the same meal, the total sorbitol load adds up even if each individual food stays within its green light range. Spacing sorbitol sources across different meals helps prevent this.
Nutritional Profile
Bok choy packs a lot of nutrition into a low-calorie package. One cup of raw bok choy provides 32 milligrams of vitamin C (about a third of your daily needs) and 32 micrograms of vitamin K (roughly a quarter of the daily value). It’s also a source of calcium, folate, and potassium. For people on a low FODMAP diet who sometimes struggle to get enough variety in their vegetable intake, bok choy is a reliable way to fill nutritional gaps without digestive risk.
Cooking Bok Choy on a Low FODMAP Diet
The biggest challenge with low FODMAP cooking is flavor. Garlic and onion, the foundation of most savory dishes, are high FODMAP. Bok choy pairs well with garlic-infused oil, which captures the flavor of garlic without the water-soluble fructans that cause symptoms. The key is using oil where garlic cloves have been heated and then removed, not minced garlic stirred into the dish.
A practical low FODMAP vegetable combination that works well in stir-fries: one cup of bok choy with eight green beans and a quarter cup of canned baby corn. All three stay within safe FODMAP limits. From there, you can layer flavor with fresh ginger, the green tops of spring onions (the white bulb is high FODMAP, but the green leaves are safe), a squeeze of lime juice, sesame oil, or soy sauce. Spice mixes work too, as long as you check the label for hidden onion or garlic powder.
Bok choy cooks quickly. Baby bok choy halved lengthwise needs only two to three minutes in a hot pan or wok. Overcooking turns it mushy and mutes its mild, slightly peppery flavor. A brief sear keeps the stems crisp and the leaves tender.