Is Grapefruit Low FODMAP?
Like most citrus fruits, grapefruit is low in fructose. But, low fructose doesn’t always mean low FODMAP. In fact, many low fructose fruits are high FODMAP. Fortunately, for those of you who like its sweet-tart taste, that’s not the case with grapefruit.
Grapefruit is low FODMAP. Half of a medium red or pink grapefruit has .21 grams of excess fructose, while half a medium white grapefruit has less than .10 grams of excess fructose. Both of these are well below the low FODMAP guideline of .40 grams of excess fructose per serving.
In this post we’ll learn a bit more about the FODMAPs in grapefruit. Grapefruit isn’t an often tested food, but there’s enough data to show grapefruit is low in excess fructose. However, the evidence for fructans in grapefruit is less clear.
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Types of Grapefruit
Grapefruit is actually a cross between two other citrus fruits, oranges and pomelos. Pomelos are the largest citrus fruit and are native to Southeast Asia. Pomelos were brought to the Caribbean in the 1600s, where they were bred with sweet oranges. This hybrid fruit is what we today know as grapefruit.1
Many people think pomelo and grapefruit are the same fruit, but there are some key differences. Like grapefruit, many varieties of pomelo are round and have flesh that ranges in color from yellow to deep pink. However, while grapefruit has a yellow-orange peel, pomelo peels are green. Pomelos are also sweeter, with a less tart or bitter taste than grapefruit.2
While all grapefruit is descended from the pinkish fleshed pomelo, you may also see white (sometimes called yellow) grapefruit in grocery stores today. These grapefruit have been bred to have a both a peel and a flesh that is light in color. It’s generally thought that the darker the flesh, the sweeter the fruit, so dark Ruby Red grapefruits will be sweeter than pink or white varieties.3
Despite differences in taste, all grapefruits have similar nutritional profiles, though white grapefruit has slightly less sugar. All colors of grapefruit are high in Vitamin C, while those with redder flesh are also a good source of Vitamin A.4 Grapefruit is also a good source of fiber and potassium and may help prevent oxalate-related kidney stones.5 Pink and red grapefruits are high in the antioxidant lycopene, which also gives tomatoes and watermelons their red color.6
You should be aware that grapefruit interacts negatively with several kinds of prescription medications. Specifically, grapefruit has negative interactions with some cholesterol and blood pressure medications, certain pain medications, some antihistamines and some psychiatric medications.7
Medications that shouldn’t be combined with grapefruit or grapefruit juice should say so on the label, but check with your doctor if in doubt. Additionally, grapefruit is not recommended for those who suffer from acid reflux, due to the fruit’s high acid content.8
If you’re eating low FODMAP and the acidity and medication interactions aren’t an issue, you may want to test your tolerance for grapefruit. Let’s look at the FODMAPs in grapefruit in more detail now.
FODMAPs in Grapefruit
Grapefruit, like all fruit, contains the FODMAP fructose. When evaluating fructose content, there are three different measures you can use: total fructose, percent fructose and excess fructose.
Regarding total fructose content, if a food has 3 grams of fructose or less per serving, it’s considered low fructose.9 Using this measure, grapefruit is low fructose, as I discuss in this post on low fructose fruits.
Alternatively, you can measure percent fructose. Under this rule, if fructose makes up less than 50% of the total sugar content in a food, the food is classified as low fructose.10 In this case, grapefruit would still be considered low fructose, because fructose accounts for about 25% of the total sugar in grapefruit.
Finally, you can measure excess fructose. This standard is used by low FODMAP researchers and compares the amount of glucose in a food to the amount of fructose. This guideline states that the amount of fructose in excess of glucose should be no more than .40 grams per serving. If another FODMAP is present in a food, then the threshold for excess fructose drops to .15 grams per serving.11
The table below contains a break down of the sugar content in grapefruit. As shown, using the FODMAP excess fructose rule, grapefruit would be classified as low FODMAP.
Sugar Content in Grapefruit
| Type | Total Sugar (grams) | Sucrose (grams) | Glucose (grams) | Fructose (grams) | Excess Fructose (grams) |
|---|---|---|---|---|---|
| Red/pink | 8.82 | 4.49 | 2.06 | 2.27 | .21 |
| White | 7.32 | 3.03 | 2.03 | 2.12 | .09 |
Source: USDA Food Data Central.
Since grapefruit has less than .40 grams of excess fructose per serving, it meets the criteria for a low FODMAP food. However, remember that if another FODMAP is present in a food, the threshold for excess fructose drops from .40 grams per serving to .15 grams per serving. In that case, only white grapefruit would still qualify as low FODMAP, at least for excess fructose.
So, are other FODMAPs present in grapefruit? That’s debatable. Many online sources report grapefruit contains fructans, but the evidence for this is sparse. Let’s turn our attention to that topic now.
Fructans in Grapefruit
Grapefruit appears on many lists of high fructan foods.12 It’s often recommend that people who have trouble digesting fructans avoid grapefruit.13 However, I’ve found that sources listing grapefruit as high fructan fail to cite any evidence for this.
It seems these sources are relying on data from the Monash University FODMAP app, which lists grapefruit as high in fructans. However, many other studies report that grapefruit is actually low in fructans.
For example, in a review of low FODMAP food lists from different countries, researchers found five lists included grapefruit. Of these, four found that grapefruit is low in fructans. Only the fifth, which happened to the Monash app, found that grapefruit is high in fructans.14
Similarly, a research report from the United States looked at low FODMAP food lists from three US-based academic institutions. The report found that only 32% of foods appeared on all three lists, meaning there is significant disagreement among US researchers on which foods are and aren’t low FODMAP. Importantly, this report specifically lists grapefruit as one of the foods with the highest level of disagreement.15
So, the research is far from clear. At present, it seems there’s more research to support the idea that grapefruit is not high fructan. In fact, the only source I could find to support the idea that grapefruit is high fructan is the Monash app.
My opinion is that there currently isn’t enough evidence to support the idea of abundant fructans in grapefruit, so the higher threshold for excess fructose should be used. Since both types of grapefruit contain less than .40 grams of excess fructose per serving, I consider it a low FODMAP food.
Conclusion: Grapefruit is a Low FODMAP Food
At present, there’s not enough evidence to prove high amounts of fructans in grapefruit. As such, this post has only evaluated grapefruit for the FODMAP fructose. Based on that, grapefruit is a low FODMAP food. Half an average sized grapefruit, 4 inches in diameter, has between .09 and .21 grams of excess fructose, well below low FODMAP guidelines.
If you’re looking for low fructose, low FODMAP fruits, grapefruit may be an option. Just keep in mind that grapefruit, like all citrus, is highly acidic. This can cause digestive issues, particularly heartburn, in many people. Also be sure to check any medications you may be taking for negative grapefruit interaction before adding this fruit to your diet.
Posts Related to “Is Grapefruit Low FODMAP?
Citrus fruits are typically low fructose at normal serving sizes. If you’re interested in learning more, I have two posts that may be helpful.
The first is a long list of fruits low in fructose. Grapefruit appears there, as does oranges.
I also have a post specifically about fructose in oranges. If you want to add citrus fruits to your diet, but can’t take the acidity of grapefruit, certain oranges may be an option.
I also have a post about FODMAPs in lemon and lemon juice. These are low fructose and low FODMAP at normal serving sizes and in normal amounts used for cooking. Lemon is a great way to add flavor to low FODMAP dishes.
About the Author
Amanda Coleman, PhD, studies food culture and teaches a popular Food and Society course. Years of digestive problems led her to live low FODMAP. Now she uses her research and analysis skills to help others understand FODMAP essentials, so they can lead better, healthier lives.
Disclaimer: the author is not a certified medical professional. Opinions expressed and content contained on this website are for informational purposes only and should not be interpreted as medical advice. Exercise caution and due diligence when using this site and the information contained herein and understand your experiences may vary.
