If your stomach is easily upset but you still want vegetables in your life, choosing the right option matters. Onions sit in a strange middle ground: technically they score an 8/10 for digestibility, but they’re also one of the top triggers people complain about.
This article compares onions with carrots, spinach, cabbage, and broccoli from a gut-first angle—who tends to tolerate which, and how to use each vegetable without paying for it later.
Onions vs carrots
Winner for digestibility: Carrots (8/10 but usually gentler)
Both onions and carrots carry an 8/10 digestibility score, but they get there in very different ways:
- Carrots: High water content, simple fibers, and much lower FODMAP content when cooked. They’re usually easy for most people, especially when soft.
- Onions: Also low in fat and protein, but high in fructans, which are classic gas and IBS triggers.
If you’re trying to build a gentler vegetable base, cooked carrots usually win. Use onions more like seasoning rather than bulk.
Onions vs spinach
Winner for digestibility: Spinach (9/10)
Spinach scores a 9/10 and behaves differently:
- Spinach: Tender leaves, relatively low fiber per serving, and quick digestion in about 1 hour when cooked.
- Onions: Denser, more fermentable fibers and a longer 2–3 hour digestion window, with more gas potential.
For many people with IBS, a small portion of cooked spinach is far safer than a big dose of onions. If your priority is a low-drama salad base, spinach wins.
Onions vs cabbage
Winner for digestibility: Tie (both 8/10, but for different reasons)
Cabbage and onions share a similar gas reputation, but they’re not identical:
- Cabbage: High in fiber, particularly the kind that ferments and produces gas. Portion size matters a lot.
- Onions: Lower in total fiber than cabbage but higher in fructans, which are potent IBS triggers.
In practice:
- People with IBS due to FODMAP sensitivity often struggle more with onions.
- People who are simply fiber-sensitive (but not strongly FODMAP-sensitive) might struggle more with cabbage.
If you’re not sure which is worse for you, test small portions of cooked cabbage and cooked onion separately on different days and track your response.
Onions vs broccoli
Winner for digestibility: Onions (8/10 vs 6/10), but with caveats
Broccoli scores a lower 6/10 and is often harder on digestion than onions:
- Broccoli: Very high in fiber and sulfur compounds that can produce intense gas and odor.
- Onions: Still gassy, but usually a bit easier if portions are controlled and they’re cooked well.
If broccoli has you doubled over, but you can tolerate a small amount of cooked onion in a dish, you’re not alone. Many people rank broccoli as the more aggressive vegetable.
Onions in a gentler vegetable rotation
If your goal is to eat vegetables without constantly upsetting your gut, you might structure your plate like this:
- Base vegetables (usually safest): Cooked carrots, potatoes, sweet potatoes, and small portions of cooked spinach.
- Medium-risk vegetables: Cabbage and onions in small, cooked portions.
- Higher-risk vegetables: Large portions of broccoli, cauliflower, and other brassicas.
In this setup, onions are a flavor ingredient—not the bulk of your vegetables. You might use a few tablespoons of sautéed onion across a whole dish instead of building a salad around raw onion slices.
Quick reference: how your gut might rank these
Many people with sensitive digestion end up with a ranking that looks like this:
- Easiest: Cooked carrots, potatoes, sweet potatoes.
- Generally easy: Cooked spinach, small amounts of cooked onions.
- Moderate: Cooked cabbage in small portions.
- Harder: Larger portions of onions, especially raw.
- Hardest: Broccoli and other gas-heavy brassicas in big servings.
The bottom line
Onions aren’t automatically the worst vegetable for digestion, but they’re a common trigger because of their fructans and acid-stimulating effects. Compared with carrots and spinach, they’re clearly harder; compared with cabbage and broccoli, they’re somewhere in the middle.
If you have a sensitive gut, think of onions as a seasoning, not a vegetable serving. Use small, well-cooked amounts for flavor and let gentler options like carrots, spinach, and potatoes carry most of the volume on your plate.
Your goal isn’t to win some imaginary toughness contest by eating huge portions of every vegetable—it’s to find a mix that your digestion can handle consistently. For many people, that means onions in moderation, not elimination.
Related reading: Want a more detailed look at onions alone? Read Onions and Your Gut: When Flavor Becomes a Digestive Gamble