One cup (133 grams) of raw parsnips contains about 24 grams of total carbohydrates, with 6.5 grams of fiber bringing the net carb count to roughly 17.5 grams. That makes parsnips a moderately starchy root vegetable, higher in carbs than most non-starchy vegetables but actually lower than white potatoes.
Carbs by Serving Size
Per 100 grams of raw parsnip, you’re looking at about 18 grams of total carbohydrates and 13 grams of net carbs (total carbs minus fiber). A whole boiled parsnip around 9 inches long comes in higher at roughly 27 grams of total carbs, since cooking softens the cell structure and you end up eating a denser portion than you would raw.
Here’s how common servings break down:
- 100g raw parsnip: 18g total carbs, ~13g net carbs
- 1 cup sliced raw (133g): 24g total carbs, ~17.5g net carbs
- 1 whole boiled parsnip (9 inches): ~27g total carbs
Where Those Carbs Come From
Parsnips get their mild sweetness primarily from sucrose, which makes up 8.5 to 10% of the root’s weight. Glucose and fructose are present in much smaller amounts, each under half a percent. The rest of the carbohydrate content is starch and fiber. If you’ve ever noticed parsnips taste sweeter after a frost, that’s because cold temperatures convert some of the stored starch into sugar.
The fiber in parsnips is predominantly insoluble, roughly 80% of the total. Insoluble fiber adds bulk and helps move things through your digestive system. The remaining 20% is soluble fiber, the type that slows digestion and can help moderate blood sugar spikes after eating. That generous fiber content (about 6.5 grams per cup) is one of the reasons parsnips perform better on blood sugar than their carb count alone might suggest. Their glycemic index sits at 52, which falls into the low range.
How Parsnips Compare to Potatoes
Parsnips are often used as a swap for potatoes in mashes, roasts, and soups, and the carb comparison favors parsnips. Per 100 grams, white potatoes contain about 21 grams of total carbs and 19 grams of net carbs. Parsnips come in at 18 grams total and 13 grams net. That’s roughly 30% fewer net carbs, thanks to parsnips having significantly more fiber.
The texture and flavor profile differs enough that you probably won’t mistake one for the other, but if you’re looking to reduce the carb density of a side dish while keeping the satisfying, starchy quality, parsnips are a solid option.
Parsnips on a Low-Carb or Keto Diet
With about 17.5 net carbs per cup, parsnips are not the easiest vegetable to fit into a strict ketogenic diet, where total daily carbs typically stay at or below 20 to 30 grams. A single cup could use up most of your daily allowance. A smaller portion, say half a cup roasted alongside other low-carb vegetables, is more realistic if you’re counting carefully.
For moderate low-carb diets (50 to 100 grams of carbs per day), parsnips fit comfortably. Their fiber content slows carbohydrate absorption, and you’d need to eat a fairly large portion before they became a problem.
What Else You Get From Parsnips
Parsnips aren’t just a carb vehicle. That cup of sliced parsnips delivers a meaningful amount of folate, vitamin C, and potassium, along with smaller amounts of vitamin K and manganese. The calorie count is modest: a full cup of raw parsnip runs about 100 calories, and even a whole boiled 9-inch parsnip is only around 114 calories.
The fiber density is the real standout. At 6.5 grams per cup, parsnips deliver more fiber than most common vegetables and many whole grains. Research on parsnip fiber composition has found that dietary fiber makes up over 30% of the vegetable’s dry matter, making it one of the more fiber-rich root vegetables you can eat.