Garlic

Garlic is one of the most universal cooking ingredients and has a long history of medicinal use — modern evidence supports modest benefits for blood pressure and cholesterol, and allicin (the compound released when garlic is crushed) has antimicrobial activity. Health-wise, for most people garlic is a net positive.

But garlic is also one of the top FODMAP triggers — it's rich in fructans, a type of fermentable fiber. In people with IBS or a sensitive gut, even small amounts can produce bloating, gas, abdominal pain, and altered bowel habits within hours. Because garlic is in nearly every savory dish — restaurant meals, sauces, soups, dressings, packaged foods — accidental exposure is a constant problem for people trying to avoid it.

Why it triggers IBS

Fructans aren't absorbed in the small intestine. They reach the colon intact, where bacteria ferment them, producing gas and pulling water into the bowel. This is the same mechanism behind onion, wheat, and many other FODMAP foods. Crucially, cooking does not break down fructans — roasted garlic is just as triggering as raw.

Lower-FODMAP alternatives

For flavor without the fructans, garlic-infused oil is well-tolerated: fructans are water-soluble and don't pass into the oil. Asafoetida (hing) in small amounts gives a garlic-like flavor and is much lower in FODMAPs. Green tops of scallions and chives also provide allium flavor without the high-fructan bulb. A registered dietitian familiar with FODMAPs can help structure an elimination and reintroduction properly.