What is the Low FODMAP Diet?
You may have landed here from our previous article on the benefits of the low FODMAP diet. If so, you know that FODMAPs are fermentable carbohydrates that can worsen the symptoms of irritable bowel syndrome and the low FODMAP diet aims to cut trigger carbs and reduce those symptoms. If not, you may want to read that post first to make sure you’re up to speed.
This post will list and explain which foods to eat and avoid during each phase of the low FODMAP elimination diet.
What to Avoid on the Low FODMAP Diet
First, we’ll discuss the major groups of carbohydrates that are classified as FODMAPs and list some of the foods that are highest in each. These are the foods you should avoid, especially during phase one of the low FODMAP diet.
During phase one, or elimination, people with IBS should choose foods with less than 1 g of total FODMAPs per serving, and the lower the better. Scroll down to the “what to eat” section for a list of foods that fit the bill .
Fructose is a simple sugar naturally present in fruits, vegetables, and honey. It has probably been a part of the human diet for millions of years, but too much of it may cause health problems in people with irritable bowel syndrome (IBS) [2, 3].
Many processed foods are sweetened with high-fructose corn syrup. Check and double check the ingredients list on all processed foods (including things like jams and sauces) to make sure that they don’t include this sweetener [4, 5, 6].
For the purposes of IBS, “excess fructose” or “fructose in excess of glucose” is the measurement to watch for, if possible. Some fructose is bound with glucose to make sucrose, or table sugar; this fructose won’t generally be a problem. Only the unbound (excess) fructose can be expected to cause problems .
People with IBS should choose foods with less than 0.15 g of excess fructose per serving. There’s more flexibility with fresh fruits and vegetables; up to 0.4 g of excess fructose per serving should be fine .
Unprocessed foods and ingredients that are high in fructose include :
- Most fruits, but especially apples and mangoes [1, 8]
- Broccoli, carrots, cauliflower, green beans, green peppers, sweet potatoes, tomatoes
- Beans & peas
Lactose, sometimes called milk sugar, is found in all milk. It is responsible for the symptoms of people with lactose intolerance, and it can also irritate people with IBS. In fact, many people with IBS are also lactose intolerant [9, 10, 11].
Milk and dairy products like yoghurt, cheese, and ice cream are, of course, highest in lactose. Goat and sheep milk are lower in lactose than cow’s milk. However, most people with food sensitivities or IBS will still react to them. To stay on the safe side, avoid all types of milk on a low FODMAP diet [12, 13, 14, 15]
Other processed foods that contain lactose include :
- Milk chocolate and candy bars 
- Pre-made sauces like pesto 
- Cheese-flavoured processed snacks 
- Pre-made puddings 
- Packaged waffles and baked goods [20, 21]
Remember: anything prepared with milk, butter, or cheese is likely to contain lactose.
One of the most common polyols (the P in FODMAP), sorbitol is a “sugar alcohol,” which just means that it is a sugar molecule with an extra hydrogen atom attached. People with IBS should choose foods with less than 0.2 g of sorbitol per serving [22, 1].
- Apple, apricot, blackberry, cherry, date, fig, nectarine, pear, peach, plum
- Avocado 
- Sugar-free gums and candies
- Diet sodas
Look for E420 as well as sorbitol in the ingredients list; this is sorbitol’s food additive code .
Mannitol is another polyol (sugar alcohol), very similar to sorbitol. In the average healthy adult, 20 g of mannitol is likely to act as a laxative and cause digestive distress. In people with IBS, much smaller amounts can be troublesome [22, 24, 8].
This sugar is scarce in natural sources. Although mushrooms and cauliflower are relatively high in it, large quantities of mannitol are industrially produced. It is added as an artificial sweetener to diabetic food, gum, and candy [23, 24].
Fructans are polysaccharides (sugar chains) made up of many fructose molecules with one glucose molecule at the end of the chain. When there are between 2 and 9 fructose units, the whole fructan is called oligofructose; when there are more than 10 units, the whole fructan is called inulin [25, 26].
Some of the foods that are highest in fructans include :
- Onions, garlic, shallots, scallions
- Wheat products, including bread and pasta
- Brussels sprouts, cabbage, broccoli, artichokes, asparagus
- Chicory root
Note that chicory root inulin may be beneficial for some people with IBS. This is one reason why it’s important to reintroduce and test FODMAPs one at a time in phase 2: some of them may actually help !
The galacto-oligosaccharides (GOS) are made up of galactose and other sugar molecules linked together in a chain. The two most common in foods are stachyose (two galactose molecules with a fructose and a glucose molecule at one end) and raffinose (one galactose, one fructose, and one glucose) [1, 28, 29].
What to Eat on the Low FODMAP Diet
Elimination diets are intimidating: there are always giant lists of foods that you’re not allowed to eat, and it looks like everything is on them. Two pieces of good news: first, you only need to cut all FODMAPs out in phase one. Second, we’ve got a list right here of foods that you can eat, all the way through every phase of the diet.
Phase 1: Elimination
This is the toughest part of the diet, because for this phase, you need to cut out as many FODMAPs as possible for up to six weeks. If the low FODMAP diet is right for you, your symptoms should start improving around week 3 or 4 at the latest [32, 8].
Very Low FODMAP
These foods are safe to eat during the elimination phase of the low FODMAP diet. They can form the backbone of your diet during the elimination phase. Choose a variety of foods from all groups or work with a licensed nutritionist to avoid possible nutritional deficiencies [1, 32, 33].
Animal Products & Dairy Alternatives
- Meat, fish, and seafood
- Lactose-free milk and yogurt
- Milk alternatives like almond, coconut, or hemp milk
- Gluten free bread
- Rice (brown and white)
- Polenta, tapioca
Vegetables & Greens
- Fennel leaves
- Bean sprouts
- Baby spinach
- Chicory leaves (remember that the root is full of inulin)
- Turnips, parsnips, carrots
- White potatoes, sweet potatoes, yams
- Zucchini and summer squash
- Bamboo shoots
- Bok choy
- Chives (use these instead of onions!)
- Bananas (though they do contain some inulin)
- Blueberries, cranberries, strawberries, boysenberries
- Citrus fruits (oranges, lemons, limes, grapefruit)
Unlike most berries, blackberries and cherries are high in FODMAPs and should be avoided .
Because all fruit contains fructose, some doctors recommend eating a maximum of one serving of fruit per meal .
- Tofu (has been fermented enough to remove GOS)
- Maple syrup, brown sugar, white sugar (in moderation, of course)
- Nutritional and brewer’s yeast, baking powder (for homemade baked goods)
- Whey protein
- Dark chocolate
- Coffee & tea (without milk)
- Salt & pepper
- Cooking oils (any type)
- Vinegar (avoid apple cider vinegar)
- Lentils (canned only)
- Button mushrooms
- Honeydew melon
- Red chili
- Fermented dairy products like kefir and sour cream
- Up to 2 tbsp of peanuts or tree nuts per meal (never pistachios or soy nuts)
Some cheeses may be safe to eat about an ounce at a time. To name a few, Swiss cheese, cheddar cheese, brie, blue cheese, mozzarella, camembert, parmesan, and feta generally have a low enough lactose content to be safe in small quantities .
During phase 1, take note of which symptoms disappear, if any, and which persist. If there’s no improvement after six weeks, stop here: the low FODMAP diet won’t do anything for you. Go back to your old diet or try something else .
Phase 2: Reintroduction
During the reintroduction phase, each subtype of FODMAP should be tested one by one. Overall, your diet should be identical to phase 1 except for whichever carbohydrate you are challenging .
In clinical settings, nutritionists recommend challenging each carb once a day for 3 days, and then returning to the low FODMAP baseline for another 2-3 days .
Alternately, you can take a cue from research settings: challenge each carb once a day for a full week, and then go back to the low FODMAP diet for another week afterward. Take note of whether symptoms returned during the challenge week, and whether they went away again the next week. This method will take considerably longer than the three-day method, but you may get clearer results .
Only challenge one carbohydrate at a time. If you reintroduce multiple carbs at once, you won’t know which one is triggering your symptoms. Later, during phase 3, you’ll reintroduce multiple FODMAP foods and learn whether any of them may be interacting .
Nutritionists recommend challenging fructose with either honey or mango. Eat 1 tsp of honey OR half a mango once a day for three days and take note of any symptoms .
Lactose is richest in dairy products, so it makes sense to challenge with dairy. Drink half a cup of milk OR eat 200 g of yogurt (regular, not Greek) per day for three days and take note of any symptoms .
It’s important to challenge sorbitol using foods that are low in fructose. You can use small amounts of foods that are sweetened with sorbitol, or you can use apricots or avocados. Eat ⅓ to ½ an avocado OR 1 small apricot per day for 3 days and take note of any symptoms .
Mannitol is significantly less common than fructose and sorbitol, but some vegetables have enough to be significant. Eat half a cup of mushrooms OR half a cup of cauliflower per day for 3 days and take note of any symptoms .
Fructans can be more troubling than the simple sugars and polyols for some people with IBS. Using a challenge of either a slice of whole wheat bread OR a cup of pasta, nutritionists recommend challenging for one day, resting for one day, and challenging for one day. Take note of any symptoms you experience on challenge days or on the day in between .
Because there are so many types of fructans, nutritionists recommend treating onion and garlic fructans as a separate challenge with the same schedule. Eat one ring of onion OR up to half a clove of garlic; these foods are very rich in fructans .
As with fructans, nutritionists recommend challenging, resting, and challenging again to test galacto-oligosaccharides (GOS). Eat half a cup of (freshly cooked, not canned) lentils OR 2 tbsp of chickpeas once per challenge day and take note of any symptoms .
Fructose & Sorbitol Combination
Fructose and sorbitol can be especially bothersome in combination, which is why some people with IBS have such trouble eating apples and pears. Eat half an apple OR half a pear once per day for three days and take note of any symptoms .
Phase 3: Personalization
Once you’ve gone through all of the challenge phases, it’s time to personalize your diet. Here, you reintroduce the FODMAPs that don’t cause symptoms, or that cause manageable symptoms, to your taste and comfort [8, 34].
Gradually increase your intake of FODMAPs that were manageable during phase 2. Try to do most of your experimentation on weekends, or other times when you’re at home for a few days, to minimize stress [8, 34].
Phase 3 is all about your comfort level and optimal health. One advantage of reintroducing certain FODMAPs is that you avoid potential nutrient deficiencies; another is that it makes your long-term diet easier to follow when you’re allowed to eat more foods. On the other hand, only you know which symptoms are tolerable and which are not; design your diet accordingly [8, 34].
Joe (SelfHacked founder) developed the SelfHacked Lectin Avoidance Diet to help himself and clients with chronic inflammation and autoimmunity figure out which foods they are reacting to. He used to have a very severe case of IBS and cured himself completely with this diet, which has similarities to a low FODMAP diet.
The SelfHacked Lectin Avoidance Diet is also an elimination-reintroduction protocol. You remove the food components that pose a high risk for those with food sensitivities until your symptoms subside, then bring them back one at a time to determine what you react to.
Once your inflammation is well-managed, you may even be able to occasionally consume some foods you are sensitive to.
Here are the resources we recommend diving into for more detailed information:
- DNA Vitamin Report and Mineral Report – lets you know which vitamins and minerals you may need more of based on your genetics, especially since low FODMAP diets can be low in certain nutrients.
- The SelfHacked Elimination Diet course, which both breaks down the science and gives you practical step-by-step instructions. The goal is to help you pinpoint your food sensitivities to plant substances and ways to overcome them.
- The All About Inflammation course provides background info and science of inflammation in a layperson-friendly way
- LabTestAnalyzer can objectively tell you if the diet you’re eating is right for you. Check to see if your diet is keeping your labs optimal.
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The low FODMAP diet includes three phases: elimination, reintroduction, and personalization. During the first phase, FODMAPs should be drastically reduced or nearly eliminated in the diet to ensure that these carbohydrates are responsible for the symptoms of IBS.
During the second phase, subgroups of FODMAPs (fructose, lactose, sorbitol, mannitol, fructans, and galacto-oligosaccharides) should be introduced one by one to see if they trigger IBS symptoms. If they don’t, they can be added back into the diet, slowly, during phase 3.
The low FODMAP diet can be intimidating because of the long lists of disallowed foods during phase 1. However, you can make delicious, nutritious meals using only the low FODMAP foods listed in this post. Plus, it’s not forever: reintroducing safe FODMAPs is just as important as eliminating bothersome ones.