Food & FODMAP tolerance database
Understand how specific foods interact with your digestive tract. Check Monash University FODMAP thresholds, digestion lag timelines, and gentle alternatives.
Garlic
Primary factor: Fructans
Garlic is one of the most potent dietary triggers for IBS. It contains high concentrations of fructans, which are short-chain fructose polymers that human digestive enzymes cannot break down. Fructans pass into the large intestine unabsorbed, where resident bacteria ferment them into hydrogen and methane gas within 6 to 18 hours, causing severe bloating, visceral pain, and altered stool form.
Onion
Primary factor: Fructans
Onions are an allium vegetable loaded with high levels of fructan oligosaccharides. Like garlic, onions cannot be enzymatically broken down in the human small intestine. When they enter the colon, rapid bacterial fermentation produces large volumes of gas, distending the bowel wall and causing significant pain, cramping, and alternating diarrhea or constipation in IBS patients.
Coffee
Primary factor: Non-FODMAP Irritant
Black coffee is chemically low FODMAP, but it is one of the most common non-FODMAP gut irritants. Caffeine stimulates the release of gastrin and cholecystokinin, which triggers the gastrocolic reflex within 15 to 45 minutes of consumption. In people with IBS-D or visceral hypersensitivity, coffee accelerates rectosigmoid motor activity, provoking sudden urgency, cramping, and loose stools.
Avocado
Primary factor: Sorbitol
Avocado is nutrient-dense but contains sorbitol, a sugar alcohol (polyol) that is slowly absorbed in the small intestine via passive diffusion. In portions larger than 30 grams (about 1/8 of an avocado), unabsorbed sorbitol reaches the large bowel, where it exerts an osmotic draw and undergoes bacterial fermentation, leading to bloating, flatulence, and loose stools 4 to 12 hours later.
Rolled Oats
Primary factor: GOS
Rolled oats are classified as low FODMAP at standard 1/2 cup (52g) dry servings. They are rich in beta-glucan, a soluble dietary fiber that forms a soothing gel in the digestive tract. However, exceeding 78 grams uncooked introduces moderate levels of galacto-oligosaccharides (GOS) and fructans, which can produce noticeable gas and bloating 6 to 14 hours later.
Cow Milk
Primary factor: Lactose
Cow milk is high in lactose, a disaccharide sugar composed of glucose and galactose. Over 65% of the human adult population has reduced lactase enzyme expression. When lactose is not cleaved in the small intestine, it exerts an osmotic draw that pulls fluid into the bowel lumen within 30 to 180 minutes, resulting in loud borborygmi, painful distension, and watery diarrhea.
Eggs
Primary factor: Non-FODMAP Irritant
Eggs contain zero carbohydrates and are strictly low FODMAP. They are an ideal source of complete protein for IBS patients on an elimination protocol. However, egg yolks contain sulfur-containing amino acids (methionine and cysteine) and dietary lipids. In some individuals, sulfur can increase foul-smelling hydrogen sulfide gas, and high fat can stimulate a brisk gastrocolic response.
Apples
Primary factor: Fructose
Apples are a double-FODMAP fruit containing both excess fructose and sorbitol. Human intestinal transporters (GLUT5) absorb fructose poorly when it exceeds glucose levels, and sorbitol further inhibits fructose uptake. This leads to substantial fluid accumulation in the small intestine, followed by vigorous bacterial fermentation in the colon, producing severe gas, distension, and diarrhea.
Bananas
Primary factor: Fructans
The FODMAP status of a banana changes dramatically as it ripens. An unripe or firm green banana contains resistant starch, which behaves as a prebiotic fiber and is low FODMAP at 100g. As the banana ripens and develops brown spots, resistant starch converts into free fructose and fructans, turning it into a high-FODMAP food that can trigger bloating and cramps.
Wheat Bread
Primary factor: Fructans
Standard commercial wheat bread is a leading dietary source of fructans. While many individuals believe gluten (a protein) is the source of their wheat distress, clinical gastroenterology research demonstrates that fructan carbohydrates are the primary trigger for gas, pain, and bowel irregularity in non-celiac patients.
Honey
Primary factor: Fructose
Honey is rich in excess free fructose, containing significantly more fructose than glucose. Human enterocytes absorb fructose via GLUT5 transporters, which have limited capacity when unsupported by glucose. Unabsorbed fructose creates a steep osmotic gradient that draws water into the small intestine, triggering rapid loose stools, followed by colonic bacterial fermentation that generates gas and abdominal spasms within 2 to 6 hours.
Watermelon
Primary factor: Fructose
Watermelon contains high concentrations of both excess fructose and mannitol (a polyol sugar alcohol). This dual-FODMAP combination exerts an aggressive osmotic effect, pulling fluid into the bowel lumen within 1 to 3 hours, before colonic bacteria ferment the mannitol and fructose into hydrogen gas, resulting in abdominal cramping, distension, and watery diarrhea.
Sourdough Bread
Primary factor: Fructans
Traditional sourdough bread is low FODMAP despite being made from wheat flour. The authentic slow fermentation process (typically 12 to 24 hours) allows wild lactobacilli bacteria and yeasts in the starter culture to consume and hydrolyze the fructan oligosaccharides into simple, easily absorbable sugars. As a result, many IBS patients who react to commercial wheat bread tolerate genuine slow-fermented sourdough without gas or pain.
Mushrooms
Primary factor: Mannitol
Fresh button, cremini, and portobello mushrooms are rich in mannitol, a polyol sugar alcohol. Mannitol is absorbed passively and very slowly in the human small intestine. In individuals with IBS, unabsorbed mannitol travels into the proximal colon, where resident microflora rapidly ferment it into gas and short-chain fatty acids, leading to severe visceral bloating and delayed cramping.
Almonds
Primary factor: GOS
Almonds contain moderate levels of galacto-oligosaccharides (GOS) and fructans. While a small portion of 10 almonds (12 grams) is clinically low FODMAP, exceeding 20 nuts delivers enough unabsorbed oligosaccharides to trigger colonic fermentation, producing gas distension and crampy lower abdominal discomfort 6 to 18 hours later.
Broccoli
Primary factor: Fructans
Broccoli's FODMAP status depends entirely on the anatomical portion eaten. Broccoli florets (the flowering heads) are low FODMAP up to 75 grams because fructans concentrate primarily in the fibrous stems and stalks. Consuming broccoli stalks delivers high amounts of fructans, resulting in colonic gas production and sulfurous flatulence 6 to 14 hours post-ingestion.
Cheddar Cheese
Primary factor: Lactose
Hard aged cheeses like cheddar, parmesan, and swiss are naturally low FODMAP and virtually lactose-free. During traditional cheesemaking, the liquid whey (where almost all lactose resides) is drained away, and remaining trace sugars are consumed by lactic acid bacteria during aging. Most lactose-intolerant and IBS patients can safely eat cheddar without digestive symptoms.
Soy Milk
Primary factor: GOS
Soy milk tolerance depends entirely on the manufacturing method. Soy milk made from whole soybeans contains high concentrations of galacto-oligosaccharides (GOS: raffinose and stachyose) that trigger severe gas, cramping, and diarrhea. Conversely, soy milk formulated with soy protein isolate is low FODMAP because the oligosaccharides are separated and discarded during protein extraction.
Kidney Beans
Primary factor: GOS
Kidney beans are exceptionally high in galacto-oligosaccharides (GOS), specifically raffinose and stachyose. Humans do not express the alpha-galactosidase enzyme required to cleave the galactose-glucose bonds in GOS. In the colon, bacteria rapidly metabolize these sugars into hydrogen, carbon dioxide, and methane gas, causing painful abdominal distension and cramping.
Wheat Pasta
Primary factor: Fructans
Standard wheat pasta made from durum semolina contains high amounts of fructans. While many people suspect gluten (a protein) as the cause of pasta-induced bloating, clinical gastroenterology studies demonstrate that fructan carbohydrates are the primary trigger for symptoms in non-celiac IBS patients. Fermentation in the large intestine causes pain, distension, and bowel irregularity 6 to 18 hours after consumption.
Peanuts
Primary factor: Non-FODMAP Irritant
Peanuts and pure peanut butter are naturally low FODMAP and contain negligible fermentable carbohydrates. However, peanuts are roughly 50% fat by weight. High fat intake stimulates the release of cholecystokinin (CCK) and peptide YY, which can trigger an exaggerated gastrocolic reflex in patients with visceral hypersensitivity, causing urgent postprandial cramping or diarrhea 1 to 3 hours after eating large portions.
Beer
Primary factor: Non-FODMAP Irritant
While standard beer is low in FODMAP sugars, alcohol and carbonation act as potent non-FODMAP gut irritants. Ethanol disrupts intestinal mucosal barrier integrity, accelerates small bowel transit, and blunts fluid reabsorption. Combined with dissolved carbon dioxide that physically distends the stomach and intestines, beer frequently triggers urgent diarrhea and upper abdominal burning within 1 to 6 hours.
Coffee with Milk
Primary factor: Lactose
Coffee with conventional dairy milk combines two potent gastrointestinal triggers: caffeine and lactose. Caffeine prompts rapid gastrin release and colonic peristalsis within 30 minutes, while unabsorbed lactose in lactase-deficient individuals creates an osmotic influx of water into the small intestine. This combination frequently produces urgent, painful diarrhea and explosive bloating shortly after consumption.
Whey Protein
Primary factor: Lactose
Whey protein concentrate (WPC) contains residual lactose from the liquid whey byproduct of cheesemaking. For individuals with low lactase activity, consuming a standard 30g scoop causes rapid osmotic fluid shifts and colonic bacterial fermentation. In contrast, Whey Protein Isolate (WPI) undergoes cross-flow microfiltration that eliminates virtually all lactose, making it well tolerated by IBS patients.
Chickpeas
Primary factor: GOS
Chickpeas contain high amounts of galacto-oligosaccharides (GOS: raffinose). However, GOS molecules are water-soluble. When chickpeas are canned in water, the oligosaccharides leach out of the bean into the brine. Draining and rinsing canned chickpeas thoroughly reduces FODMAP content to a safe low-FODMAP level at 1/4 cup (42g), whereas boiled dry chickpeas remain high in GOS.
Dark Chocolate
Primary factor: Non-FODMAP Irritant
Dark chocolate (85%+ cocoa) is naturally low in lactose and fermentable carbohydrates, making it safe for low FODMAP diets up to 30 grams. However, dark chocolate contains natural methylxanthines (caffeine and theobromine) along with high cocoa butter fat, which can stimulate gastrointestinal motility and lower esophageal sphincter relaxation in sensitive individuals.
White Rice
Primary factor: Non-FODMAP Irritant
White rice is the clinical gold-standard low FODMAP, low-residue carbohydrate for IBS and IBD patients. Made almost entirely of amylose and amylopectin starch, white rice is broken down by salivary and pancreatic amylase in the upper small intestine and absorbed completely as glucose, leaving zero unabsorbed fermentable sugars for colonic bacteria.
Chicken Breast
Primary factor: Non-FODMAP Irritant
Plain chicken breast is 100% protein and moisture, containing zero fermentable carbohydrates, fructans, or lactose. It cannot cause colonic gas fermentation or osmotic diarrhea. Any gastrointestinal distress experienced after eating chicken breast is almost universally caused by allium marinades (garlic and onion powder), excessive cooking oils, or added spice rubs containing high-FODMAP thickeners.
Tomatoes
Primary factor: Fructose
Fresh common round tomatoes and Roma tomatoes contain equal ratios of glucose and fructose, making them low FODMAP in standard servings up to 119 grams. However, tomatoes are naturally acidic and contain histamine-liberating compounds. In patients with gastroesophageal reflux or histamine sensitivity, tomato consumption can trigger epigastric burning, reflux, and accelerated bowel motility without colonic fermentation.
Kombucha
Primary factor: Fructans
Although widely marketed for gut health, kombucha is frequently a potent symptom trigger for individuals with IBS and SIBO. Kombucha fermentation leaves residual fructans and excess free fructose, while the live yeasts and acetic acid bacteria can provoke rapid gas production, dysmotility, and severe bloating in visceral hypersensitive intestines.
Test your personal triggers with GutLog on iOS
Population tables cannot replace personal tracking. GutLog 1.5.6 tests your individual reactions across 6 digestion lag windows using a Poisson arrival baseline model.