Is Sweet Potato Low FODMAP?

Key points:

• Sweet potato is low FODMAP when eaten in small portions so it’s really dependent on your serving size.
• A serving size of ½ cup (75g) of sweet potato is low in FODMAPs and is likely to be tolerated by most individuals with IBS.
• The FODMAP culprit in sweet potato is mannitol, a naturally occurring polyol (a type of a type of short-chain carbohydrate), that's poorly absorbed in the digestive system for some individuals. 

Sweet potatoes are a nutritional powerhouse. Not only do they taste great, they contain dietary fibre, vitamin A & C, specific minerals and antioxidants. Fortunately, sweet potatoes do fit in the FODMAP diet, but just like many other veggies, serving size matters.

Sweet potatoes are low FODMAP in servings of ½ cup (75g) per meal, according to the Monash University FODMAP Diet App. Once you hit a ⅔ cup (100g) serving, it’s moderate in FODMAPs. More specifically, it contains moderate amounts of the polyol mannitol. A large serving of ¾ cup (112g) is considered high FODMAP.

Mannitol is a naturally occurring polyol (the ‘P’ in FODMAP), or a type of short-chain carbohydrate found in some fruits and vegetables that can trigger symptoms of medically diagnosed Irritable Bowel Syndrome (IBS).

How to eat sweet potato on a low FODMAP diet

Boiled, steamed, baked, fried… sweet potatoes are versatile. And while it can be hard to stick to ½ a cup of sweet potato in one sitting, what’s important to note is that you can enjoy sweet potatoes on a low FODMAP diet. You can eat sweet potato in a variety of ways:

• Mashed sweet potatoes
• Roasted sweet potatoes
• Oven-baked sweet potato cubes tossed in a green or quinoa salad
• Added in a frittata
• Added in a soup
• Added in a stew
• Added in Shepherd’s Pie as the topping (just keep a close eye on how much you consume).

It’s also important to note that when preparing sweet potato, avoid pairing it with high FODMAP ingredients such as onion, garlic and leek, as small amounts may trigger symptoms. Overall, make sure the rest of your meal is low in FODMAP by using other low FODMAP foods to ensure that symptoms are contained. 

What about sweet potato fries?

Since sweet potatoes are safe in ½ cup portions, try mixing them with regular white potatoes (which are low FODMAP in large amounts) for a more generous serving size. But you might want to avoid the store-bought aioli as it can be high in FODMAPS due to added garlic.

Sweet potatoes vs yams

Sweet potatoes and yams are often used interchangeably. While sweet potatoes and yams are both starchy vegetables (also known as tubers) that are rich in carbohydrates, and look quite similar, they do not have the same FODMAP content.

Both sweet potatoes and yams are low FODMAP at ½ cup (75g) small servings, however, yam is lower in FODMAPs and only becomes a moderate FODMAP food at 2 cups per meal (300g), compared to sweet potato which is moderate in FODMAPS at a ⅔ cup serving (100g). 

And while the FODMAP culprit in sweet potato is mannitol, a naturally occurring polyol, the FODMAP culprit in yams are fructans - another type of naturally occurring sugar that’s poorly absorbed in our intestines. 

So if you’re choosing between a sweet potato and a yam, yams are a better choice if you want to eat larger amounts of a tuber vegetable.

Summary

There’s no reason to break up with sweet potatoes while on a low FODMAP diet, but serving size matters. A small ½ cup serve of sweet potato is low FODMAP and can be enjoyed in a variety of ways. A serving of  ⅔ cup (100g) is moderate in FODMAPs, while a large ¾ cup serving (112g) is considered high FODMAP. Yams, while often mistaken for sweet potatoes, are a different vegetable and are lower in FODMAPs than sweet potatoes. 

Need help with the low FODMAP diet? Our FREE dietitian developed program will guide you through it, step-by-step. Includes a low FODMAP food guide. Sign up now.

If you are experiencing gut symptoms and have not been recommended a low FODMAP diet by a healthcare professional, get started with the manage your gut symptoms program.

Reviewed by healthylife health experts February 2023.