The short version
FODMAP stands for the four categories of short-chain carbs that ferment in the large intestine[3]. For FODMAP-sensitive people - roughly 10 to 15 percent of adults, heavily overlapping with IBS - these carbs trigger bloating, gas, and pain 1 to 4 hours after meals. That timing overlap is why bloating 2 hours after lunch is one of the clearest clinical hints that FODMAPs are worth testing. The framework is not a permanent diet. It is a diagnostic protocol: eliminate all four, then reintroduce one at a time to find your specific triggers.
Oligosaccharides
Oligosaccharides are chains of 3 to 10 sugars. They break down into two sub-groups: fructans and galacto-oligosaccharides (GOS).
High-FODMAP fructans:
- Wheat, rye, barley (in any bread or grain form)
- Onions (all forms, including in stock)
- Garlic (all forms, including in stock)
- Leeks, shallots
- Artichoke
- Inulin (a common prebiotic fiber added to foods)
High-FODMAP GOS:
- Beans and lentils (chickpeas, black beans, kidney beans, navy beans)
- Soybeans
- Hummus in typical portions
- Cashews, pistachios
Oligos are usually the biggest IBS trigger category. Garlic and onion hide in almost every restaurant dish, soup, stock, sauce, and seasoning blend, which is what makes dining out difficult.
Low-FODMAP substitutes: garlic-infused oil (the flavor, no FODMAP because fructans are not fat-soluble), scallion greens only (not the white base), sourdough spelt bread (long fermentation reduces fructans), canned drained chickpeas in small portions (rinsing removes some GOS). If you suspect overlapping wheat sensitivity, the hidden gluten and dairy guide covers the packaged-food categories that trip up wheat-restricted eaters.
Disaccharides
Disaccharides are 2-sugar chains. The FODMAP-relevant one is lactose - the sugar in milk.
High-FODMAP (lactose):
- Milk (cow, goat, sheep)
- Soft cheeses (ricotta, cottage cheese, cream cheese)
- Ice cream, frozen yogurt
- Yogurt (regular, not Greek-strained)
- Whipping cream
- Sweetened condensed milk
Naturally low-lactose (OK for most FODMAP-sensitive):
- Aged hard cheeses (cheddar, parmesan, Swiss, gruyère - lactose converts during aging)
- Butter (almost no lactose)
- Greek yogurt strained (most lactose removed in straining)
- Lactose-free milk and products
Lactose intolerance and FODMAP sensitivity are related but distinct. Lactose intolerance is a deficiency of lactase enzyme; FODMAP sensitivity is a broader gut response. Both respond to the same fixes.
Monosaccharides
The FODMAP-relevant monosaccharide is excess fructose. Fructose is absorbed by a different mechanism than other sugars, and some people's small intestines can't keep up with high doses.
High-FODMAP (excess fructose):
- Apples, pears, mangoes, watermelon
- Honey, agave syrup, high-fructose corn syrup
- Dried fruit (concentrated fructose)
- Fruit juices (fructose without fiber buffer)
Low-FODMAP fruits:
- Berries (strawberries, blueberries, raspberries)
- Citrus (oranges, lemons, limes)
- Bananas (firm, not overripe)
- Grapes
- Pineapple
- Kiwi
The key distinction is fructose:glucose ratio. Fruits with roughly equal or lower fructose than glucose are tolerated well. Fruits where fructose exceeds glucose cause the FODMAP response. This is why an apple (fructose-dominant) triggers symptoms and a banana (balanced) usually does not.
Polyols
Polyols are sugar alcohols. They occur naturally in some fruits and are heavily used in sugar-free products.
High-FODMAP polyols:
- Sugar alcohols: xylitol, sorbitol, mannitol, maltitol, erythritol, isomalt (check labels)
- Sugar-free gum and mints
- Sugar-free candy, "keto" desserts
- Stone fruits: cherries, peaches, plums, apricots, nectarines
- Apples, pears (also high-fructose, double-trouble)
- Mushrooms
- Cauliflower (in larger portions)
Sugar alcohols in "sugar-free" labeled products are near-guaranteed to bloat FODMAP-sensitive bodies. A single piece of sugar-free gum can trigger substantial symptoms. Stone fruits and mushrooms are moderate triggers in typical portions.
How to use this sheet
The cheat sheet is for reference. The actual protocol has three phases:
Phase 1 - Strict elimination. All four categories, 2 to 3 weeks. You eat only low-FODMAP foods. Symptoms should reduce noticeably in 7 to 10 days if FODMAPs are your issue. The Monash FODMAP app is the canonical food-by-food reference.
Phase 2 - Category-by-category reintroduction. One category per week. Start small (say, half a serving of an oligosaccharide food), escalate through the week. Log symptoms. At end of week, you know whether that category is tolerated. Continue to the next category.
Phase 3 - Personalized long-term diet. You now know which of the 4 categories (and specific foods within them) are your triggers. Most people tolerate 2 to 3 of the 4 categories after testing. The long-term diet is much less restrictive than strict elimination.
Staying on strict low-FODMAP beyond 6 to 8 weeks is actively not recommended - it reduces gut microbiome diversity[1]. The protocol is diagnostic, not therapeutic. For short windows of gut discomfort that are not FODMAP-driven - a rough food week, travel, a heavy weekend - a 3-day gut reset is the lower-commitment tool.
When to see a doctor
Before starting the protocol, confirm that FODMAP sensitivity is actually the issue. Get celiac disease ruled out (it's not a FODMAP problem and requires a different approach). Get inflammatory bowel disease ruled out if symptoms include bleeding, weight loss, or fever. A dietitian with Monash certification is strongly recommended for the reintroduction phase - getting phase 2 wrong means you either give up too early or land on an unnecessarily restrictive long-term diet.
