After re-challenging high FODMAP foods, people with IBS find they can enjoy a much more varied and nutritious diet. There is a common pitfall, however: overloading on too many of these foods at once, which may trigger symptoms. Here are 3 key things to know to avoid overlading on FODMAPs:
1. This is the “low” FODMAP diet, not the “zero” FODMAP diet.
Have you ever wondered whether you could eat too many foods that, although they are individually low in FODMAPs, together could add up to a high FODMAP load? Or how many high FODMAP foods you can tolerate at once? This is what we mean by “stacking” or “loading”.
The answer is both-sided: “yes”, you could eat too much of a good thing but also “no”, depending on which foods you choose. Some foods have only trace amounts of FODMAPs or none at all, for example, quinoa, carrots, kale, and can be eaten in large quantities. Others are considered low FODMAP only at specified (often small) portions.
For example, zucchinis are low in FODMAPs at a ½ cup serving (about 2 oz.) but larger quantities (starting at 3.5 oz.) are high in oligosaccharides, making them a high FODMAP choice. You need to pay attention to portion sizes of these foods, especially during the elimination phase. An expert dietitian can help you learn which foods you need to be cautious with and give you the right resources to guide your food choices. Tip: don’t trust everything you read online. Several lists circulating on the web are inaccurate or outdated.
2. Test your FODMAP threshold
Once you have completed the elimination and re-challenge phases of the low FODMAP diet, and have discovered which high FODMAP foods you tolerate, you need to test your tolerance to combinations of these foods and find out your own FODMAP threshold.
You can start by combining two high FODMAP foods on the same day or in the same meal. For example, you may know you tolerate 1 cup of plain yogurt (which contains lactose) and ½ cup of blackberries (rich in sorbitol) as you tested them separately in the re-challenge phase. If you enjoy topping your yogurt with blackberries, you can now try that combination. If that’s ok, you can have that snack two or three days in a row and see how your body reacts.
3. Make sure you do this gradually: the effects are additive
A common mistake is to start with too many foods too soon. One of the biggest triggers for symptoms is one of Americans’ favorite foods: pizza! Let’s say you know you can tolerate lactose (in the cheese), wheat oligosaccharides (in the crust), and small amounts of mannitol, so you decide to celebrate by going out and ordering a large pizza with mushrooms (rich in mannitol) and artichokes (high in fructose) at your first pizza outing. Ouch! It would be more prudent to start with a plain pizza (crust, tomato sauce, and cheese), and eat one slice at first. See if you tolerate it and build up from that. Next time you can try a slice of pizza with mushrooms or two slices of the plain pizza.
It also helps to keep the rest of your day’s food intake low in FODMAP when you plan to go out for that pizza. If you eat a high FODMAP breakfast or lunch and eat pizza for dinner, your GI tract may be overloaded with FODMAPs by dinner time, as the effects of FODMAPs are additive, and by the late evening or the next morning, you may be having symptoms. Use your judgment and listen to your body. It will be thankful.