Sweet potatoes are considered a low FODMAP food. Although they do contain fructose, they contain more glucose, and that excess of glucose means that sweet potatoes are generally well tolerated even in those with IBS.
If that’s a little confusing to you, don’t worry. I’ll break down things as simply as possible in the rest of this post.
FODMAP Breakdown of Sweet Potatoes
One research team analyzed the carbohydrate content of sweet potatoes.
They tested several varieties of sweet potato, so we can get a pretty detailed view of what the typical tuber contains in terms of sugars and starches.
This first table below shows the main sugars fructose, glucose, and sucrose in both raw and cooked versions of different strains of potatoes:
It’s clear that sweet potatoes contain a significant amount of fructose, which is a FODMAP.
Values ranged from 11.1-19.8 mg of fructose per gram of cooked potato.
While that seems bad, it’s important to note that there was more glucose than fructose in every single sweet potato.
Research has shown that when there is as much or more glucose than fructose, the food is digested more easily.
Part of the definition of a high FODMAP food is:
FODMAPs are poorly absorbed short-chain carbohydrates including fructose (in excess of glucose)…
Let’s take a look at the remaining sugar breakdown from that original study before summing things up.
The table below shows maltose, raffinose, stachyose, and verbascose. Note that maltose is not a FODMAP sugar.
The amount of raffinose is relatively small, but still significant.
Overall, it’s clear that while sweet potatoes do contain FODMAPs, they are relatively low in FODMAPs compared to other foods.
Are Sweet Potatoes OK for IBS?
Even though there are FODMAPs in sweet potatoes, they’re usually okay to eat even if someone has IBS.
The fact that the levels of FODMAPs in sweet potatoes are reasonably low, plus that they have more glucose than fructose means that they are generally well tolerated.
Research on IBS usually includes sweet potato (along with all other types of potatoes) in their list of foods that are typically safe to eat (source):
The types of foods and beverages that are better tolerated include water; rice; plain pasta or noodles; baked or broiled potatoes; white breads; plain fish, chicken, turkey, or ham; eggs; dry cereals; soy or rice based products; peas; applesauce; cantaloupe; watermelon; fruit cocktail; margarine; jams; jellies; and peanut butter.
Not surprisingly, most of those foods are also low in FODMAPs (e.g. peanut butter is low FODMAP).
Note that baking or broiling sweet potatoes is recommended instead of frying them in a lot of oil, which can cause additional stomach problems.
Finally, remember that quantity matters. For most people, eating a small sweet potato won’t cause digestion troubles, but eating a much larger serving might. You’ll need to test your limits to establish where you might have to draw the line.