All About Potatoes & FODMAPs
This Explore an Ingredient entry covers sweet potatoes, both brown skinned and purple skinned, as well as what Monash University refers to as simply “potatoes”, which encompasses starchy Russet and Idaho-type potatoes (typically used for baked potatoes), and gold and yellow-skinned, red-skinned and purple potatoes, which are waxier and less starchy.
The Good News – Potatoes Are Low FODMAP
Potatoes (Solanum tuberosum) have shown no detectable FODMAPs in lab testing, per reports from Monash.
Monash researcher’s recommendation is to “eat freely and according to appetite”. (With the caveat that a serving size is “½ a medium” potato at 2 ¾ oz [75 g] and that healthy eating guidelines recommend 5 servings of vegetables per day).
Potatoes are part of the nightshade family, as are tomatoes and eggplant. Nightshades are not an issue from a FODMAP perspective.
There are close to 4,000 varieties of potato and they were first documented as far back as 8000 BC.
Also Known As…
In some parts of the world potatoes might be referred to as spuds, tatties or taters.
Sweet potatoes (Ipomoea batatas) are only distantly related to the potatoes described above. See sweet potatoes below.
The Monash app listing for sweet potatoes gives us Green Light low FODMAP portions of ½ cup (75 g) and Yellow Light moderate FODMAP portions of 2/3 cup (100 g).
What is important to note here is that you can have sweet potatoes.
Also note that they do veer into Moderate territory quickly, so portion control is important.
FODMAP Friendly has lab-tested purple skinned, white fleshed sweet potatoes and they say a low FODMAP serving size is ½ cup (75 g) as well.
As always, YOUR tolerance is what is important, so assessing your own reactions during a structured Challenge Phase is paramount.
Please read our article, What Is A Low FODMAP Serving Size?, which will be helpful.
For sweet potatoes in particular, note that Monash has tested orange fleshed sweet potatoes, which are often labeled as “yams” in U.S. markets.
True yams (Dioscorea alata) are a different vegetable, FYI. Monash has tested them as well and they are Green Light low FODMAP in 1 cup (75 g) portions but do not hit Yellow Light moderate until 2 cup (300 g) portions.
FYI the New Zealand yam is Oxalis tuberosa.
How to Buy
For all potatoes we recommend buying in bulk so that you can hand pick each potato.
Potatoes often come pre-bagged, and might even be less expensive this way, but you have no assurance that you will not end up with bruised or rotten potatoes.
Potato skin should be blemish free, with no sprouting eyes or rotting areas.
Don’t Buy Green Potatoes
If potatoes are sporting a green color, do not buy them.
A green color on potato skins indicates that they have been stored exposed to light – either sunlight or even fluorescent light – and the color indicates the presence of solanine, which is a natural toxin that can trigger digestive upset.
How to Store
Potatoes should be stored in a well-ventilated cool, dark place.
Temperatures of about 45°F to 50°F (7°C to 10°C) are best for short-term storage and most potatoes will last in the average home for a couple of weeks.
Proper storage should prevent the development of any green color and retain their texture.
Do not refrigerate. Temperatures below 39°F (4°C) will convert the starches to sugar, which alters their taste, texture and how they react during cooking.
Any potatoes that are soft, mushy, develop a green cast, grow extensive eyes or show any rotten areas should be discarded.
How to Prep
If you have any potatoes at home that have developed a greenish cast, there are a few approaches to consider.
If there are a couple of sprouted eyes (see below) or small spots that have turned green, you can trim them away and still use the potato.
But if the potato has developed a green cast over a larger area, discard the potato.
All potatoes should be washed right before using and not before.
Starchy potatoes, such as Russets and Idaho potatoes are often peeled, although they do not have to be. They do always need a good scrub, as they can be quite dirty and dusty.
Waxier potatoes can be used with the skin, which is tender, or they, too, can be peeled.
Once peeled they should be used right away or you can store them in cold water, which will remove some of the starch, which will leach into the water. Follow individual recipes for directions and sometimes you want to remove the starch and sometimes you need it.
Depending on your final usage you might want to excess starch removed or not, so use this technique only when appropriate and directed to do so.
How to Cook
Let us count the ways! Boiled, steamed, pan-fried, sautéed, baked, nuked in the microwave, deep-fried, grated, shredded, julienned, mashed, smashed, cold in salads, made into chips, fries or potato pancakes, hash browns or home fries…potatoes are versatile!
We have many low FODMAP recipes for you, including: (also see the sidebar for the latest potato recipes!)
- Mashed Potatoes for a Crowd
- The Best Oven-Baked Fries
- Low FODMAP Home Fries
- Hash Browns
- Mashed Sweet Potatoes
- Vegan Mashed Potatoes