First things first—no, watermelon is not low FODMAP. It’s a high FODMAP fruit, even in small servings. It’s also high in multiple FODMAP categories, making it a common trigger for many people with irritable bowel syndrome (IBS).
This article will teach you why watermelon frequently triggers IBS symptoms, how much watermelon is considered low FODMAP (hint: it’s not much), safer low FODMAP fruit alternatives, and how to manage symptoms if you’re unable to avoid watermelon completely.
What are FODMAPs?
FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. They’re fermentable carbohydrates that can trigger digestive symptoms and gastrointestinal distress in people with IBS because they’re poorly absorbed in the small intestine.
Since they’re poorly absorbed, FODMAPs reach the large intestine intact. This is where your gut bacteria rapidly ferment them, leading to symptoms like gas, bloating, diarrhea, and abdominal discomfort.
There are five FODMAP categories:
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Fructans (oligosaccharides)
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Galacto-oligosaccharides (GOS, also oligosaccharides)
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Lactose (disaccharide)
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Excess fructose (monosaccharide)
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Polyols (sorbitol and mannitol)
Different food groups, such as fruits, vegetables, grains, and dairy, can contain varying levels of FODMAPs. While some foods only contain one type of FODMAP, others may contain two or even three different FODMAP categories.
The low FODMAP diet has been studied for over 20 years, and studies have shown that around three-quarters of people with IBS experience symptom relief when following it. It has three distinct phases:
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Elimination phase
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Reintroduction phase
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Personalization phase
It's important not to stay in the elimination phase for too long, as this can be detrimental to long-term gut health and overall nutritional adequacy (not to mention being mentally challenging—avoiding a long list of foods can make it hard to enjoy eating!).
Tips for Following a FODMAP Diet
Successfully managing IBS symptoms with a FODMAP diet takes planning and attention to detail. Here are some practical tips to help you stay on track:
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Identify trigger foods: Keep a food diary to help pinpoint which foods cause your IBS symptoms.
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Choose low FODMAP fruits: Opt for fruits like unripe bananas, berries, and citrus, which are naturally low in FODMAPs and less likely to trigger symptoms.
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Read labels carefully: Watch out for high FODMAP ingredients such as high fructose corn syrup, lactose, and certain sugar alcohols in packaged foods.
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Try lactose-free and almond milk: These alternatives are low in FODMAPs and can be used in recipes or with cereals.
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Focus on plain cooked meats and low FODMAP vegetables and grains: These foods are typically low in FODMAPs and can form the foundation of your meals.
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Use the Monash University app: This app is a valuable resource for checking the FODMAP content of different foods and making informed choices.
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Reintroduce foods gradually: During the reintroduction phase, add foods back one FODMAP category at a time to identify which ones trigger symptoms.
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Watch your portion sizes: Even low FODMAP foods can cause symptoms if eaten in large amounts, so stick to recommended serving sizes.
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Seek professional support: A registered dietitian can help you navigate the FODMAP diet, tailor it to your needs, and manage your IBS symptoms effectively.
Remember, the low FODMAP diet is meant to be temporary, and it's important to move forward with food reintroductions to determine your personal triggers and FODMAP thresholds (i.e., what portion sizes you can tolerate).
Is Watermelon Low FODMAP?
No, watermelon is not low FODMAP. Watermelon is high in FODMAPs and can be particularly problematic for people with IBS, as it may trigger symptoms like bloating and diarrhea. A standard serving of watermelon is about 150 grams (roughly 1 cup), which is high in excess fructose, fructans, and mannitol (a sugar alcohol).
Here’s how each FODMAP affects digestion:
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Fructose malabsorption occurs because watermelon contains more fructose than glucose (another monosaccharide). This overwhelms the specialized transporters, leading to excess fructose entering the colon. It is then fermented by gut bacteria, producing gas (which can worsen abdominal pain and bloating). It also has an osmotic effect, drawing water into the bowels. This can trigger diarrhea in some people.
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Mannitol (and other sugar alcohols) are not fully broken down by the human body. Sugar alcohols are also fermented by the gut bacteria and draw water into the bowels, which can worsen gas, bloating, abdominal pain, and diarrhea.
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Fructans are not digested by the human body because we lack the necessary enzymes. They are rapidly fermented by the gut bacteria, producing gas. This can produce painful gut symptoms in people with fructan intolerance.
Even very small portions of watermelon or watermelon juice can trigger symptoms in people with a FODMAP intolerance.
Watermelon Serving Size and IBS Tolerance
While some high FODMAP foods can be tolerated in smaller portions, watermelon typically isn’t one of them. That’s because even very small amounts of one tablespoon still contain a moderate amount of excess fructose. If excess fructose is one of your triggers, even small amounts of watermelon could lead to developing symptoms.
All in all, watermelon isn’t the best food for FODMAP intolerance because it contains multiple types of FODMAPs, making it more likely to trigger symptoms.
Common IBS Symptoms After Eating Watermelon
Like other high FODMAP foods, watermelon can cause digestive symptoms like:
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Gas
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Bloating
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Abdominal cramping
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Diarrhea or loose stools
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Urgency
Symptoms may appear in the first hour or two after eating, but for most people, FODMAP-related symptoms start 4 to 8 hours after a meal.
What Fruits Are Low FODMAP?
Fortunately, there are plenty of low FODMAP fruits and vegetables you can enjoy instead of watermelon. Including a variety of these fruits and vegetables in your diet is important for maintaining nutritional balance and managing IBS symptoms.
Remember, certain fruits are lower in FODMAPs, so if you're on the elimination phase of the low FODMAP diet, fruits should be chosen based on their FODMAP content. Be sure to pay attention to the serving size, as some fruits can be high FODMAP in larger portions. Additionally, be mindful of eating multiple servings of fruit in one sitting, as this can increase the total FODMAP load and may trigger symptoms.
What Fruits Are High FODMAP
If watermelon causes your IBS symptoms to worsen, you may also struggle with other high FODMAP fruits. During the elimination phase of the low FODMAP diet, it is important to avoid high FODMAP foods, including high FODMAP fruits such as:
Instead, choose lower FODMAP fruits like the ones listed above. This ensures you can still reap the health benefits of fruit while keeping your symptoms under control.
How to Manage Fruit-Related IBS Symptoms
If you find that eating fruit triggers your IBS symptoms, here are some practical strategies for minimizing discomfort:
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Choose lower FODMAP fruits such as the ones listed above
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Stick to low FODMAP serving sizes
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Limit how many servings of fruit you eat per meal, as even low FODMAP fruits can contribute to the overall FODMAP load
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Avoid eating multiple small portions of high FODMAP fruits, as these can add up to a high amount of FODMAPs
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Eat fruits with a meal rather than on an empty stomach, as this can improve tolerance
Balancing all food groups—including fruits, vegetables, grains, and dairy—is important to ensure a nutritionally complete low FODMAP diet while reducing gastrointestinal symptoms.
Some people also find it beneficial to take digestive enzyme supplements to help break down the fructans found in certain high FODMAP fruits. However, there are currently no enzyme supplements to break down sugar alcohols or excess fructose, so keep that in mind if they are triggers for you.
Using FODZYME With High FODMAP Fruits
FODZYME is a digestive enzyme powder that helps break down three FODMAPs: fructans, GOS, and lactose. If you struggle with fruits high in fructans (such as ripe bananas and persimmons), FODZYME can help break down these fructans, making these foods easier to digest and tolerate.
If you're sick of having a long list of foods to avoid with IBS, try FODZYME and see how it can reduce the stress around eating and reduce digestive symptoms like gas, bloating, and abdominal discomfort.