Seitan is low FODMAP. Monash University, the leading authority on FODMAP testing, classified wheat gluten as low FODMAP in their analysis of common plant-based foods. This surprises many people because seitan comes from wheat, and wheat is one of the most well-known high-FODMAP foods. The difference comes down to what’s actually in seitan versus what’s in a slice of bread.
Why Wheat Is High FODMAP but Seitan Isn’t
The FODMAPs in wheat are fructans, a type of short-chain carbohydrate found in the starchy part of the grain. When you make seitan, you wash wheat flour repeatedly until the starch dissolves away, leaving behind mostly protein. That washing process removes the bulk of the fructans along with the starch.
The numbers reflect this clearly. A 100-gram serving of seitan contains about 25 grams of protein but only 6 to 7 grams of carbohydrates. Compare that to 100 grams of whole wheat bread, which has roughly 50 grams of carbs. With so little starch remaining, there simply isn’t enough fructan left to trigger symptoms in most people with IBS.
Seitan vs. Celiac Disease
This is the critical distinction that trips people up. A low FODMAP diet and a gluten-free diet solve two completely different problems. FODMAPs are fermentable carbohydrates that cause bloating and discomfort in people with IBS. Gluten is a protein that triggers an immune reaction in people with celiac disease. Seitan is essentially pure gluten, so it’s safe for IBS-related FODMAP restrictions but absolutely off-limits for anyone with celiac disease or a confirmed wheat allergy.
Watch Out for Store-Bought Seitan
Plain seitan made from vital wheat gluten and water is low FODMAP. The problem is that most commercial seitan products don’t stop there. Manufacturers commonly add garlic, onion powder, soy sauce made from wheat, or “natural flavors” that can contain garlic or onion derivatives. According to Monash University’s label-reading guidelines, even small amounts of onion and garlic in powder form contribute significantly to a food’s FODMAP load. These aren’t ingredients you can safely ignore on a label.
Other common additions to watch for include inulin, fructooligosaccharides (FOS), chickpea flour, and soy flour. All are high-FODMAP ingredients that manufacturers use to boost nutrition or improve texture. The phrase “vegetable powder” or “dehydrated vegetables” on an ingredients list often means garlic or onion is hiding in the mix. If a product lists “natural flavor” or just “flavors,” that can also include garlic or onion juice, particularly in products regulated as meat alternatives.
Making Seitan at Home
Homemade seitan gives you full control over what goes in. The base is simple: vital wheat gluten mixed with water or low-FODMAP broth, then simmered, steamed, or baked. The challenge is seasoning it well without reaching for garlic and onion, which are the backbone of most seitan recipes you’ll find online.
Garlic-infused oil is your best friend here. Fructans don’t dissolve in fat, so oil that’s been infused with garlic carries the flavor without the FODMAPs. You can also find lab-tested garlic and onion powder replacements from brands like FreeFod, which has been certified low FODMAP by FODMAP Friendly. Beyond those swaps, most individual herbs and spices are naturally low FODMAP. Cumin, smoked paprika, ginger, chili flakes, fennel seeds, turmeric, and black pepper all work well for building savory depth. Soy sauce is fine in small amounts (about one tablespoon), or you can use tamari for a slightly richer flavor.
Toasting whole spices briefly in a dry pan before grinding them releases more aromatic oils and gives homemade seitan a richer, more complex flavor than simply dumping in pre-ground spices from a jar.
How Seitan Compares to Other Plant Proteins
For anyone following a low FODMAP diet and eating plant-based, protein sources can feel limited. Seitan is one of the most protein-dense options at 25 grams per 100-gram serving. Firm tofu and tempeh are also low FODMAP and provide around 20 grams of protein per 100-gram serving. All three are considered safe choices for vegans on a low FODMAP diet.
Canned and drained legumes like chickpeas, lentils, and butter beans are low FODMAP only in small portions, roughly a quarter cup per meal. The canning and draining process leaches out some of the water-soluble FODMAPs, which is why canned versions are better tolerated than dried beans cooked from scratch. Peanut butter is another reliable low-FODMAP protein source. If you’re trying to hit adequate protein intake without triggering symptoms, rotating between seitan, tofu, tempeh, and small portions of canned legumes gives you the most variety.
Portion Size Still Matters
Monash University’s low FODMAP rating for wheat gluten was based on a standard serve. While seitan tested very low in fructans (scored 0.13 per serve in the Monash analysis), eating dramatically large portions of any borderline food can push your total FODMAP intake past your personal threshold. A typical serving of seitan, around 100 grams, is well within safe territory for most people. If you’re in the elimination phase of the low FODMAP diet, stick close to standard portions and note how you respond before scaling up.