Few foods spark as much debate over calorie content as the potato: some treat it as a harmless side dish, others blame it for weight gain. The truth leans much closer to the first camp, especially when it comes to potatoes boiled plain, without butter or other rich add-ons.

Basic calorie count

Plain boiled potatoes, whether cooked in their skins or peeled, without added fat or salt, run around 80-90 calories per 100 g. For comparison, that’s noticeably less than rice or pasta by the same cooked weight, and far less than fried potatoes, where calories can climb 2-3x higher just from absorbed oil. A medium boiled potato weighing about 150 g comes in around 120-135 calories — a fairly modest number as side dishes go.

Where those calories come from

Potatoes are mostly water — roughly 75-80% by weight when raw — plus carbohydrate in the form of starch, which supplies almost all of their calories. Protein content is modest, around 2 g per 100 g, and fat is essentially negligible, just a fraction of a gram. That’s exactly why plain boiled potato is such a low-calorie food on its own: the calorie load in most potato dishes usually comes not from the potato itself but from what gets added to it — butter, sour cream, mayonnaise, or cheese.

Why potatoes get blamed for being “fattening”

The potato’s reputation as a calorie-heavy food has much more to do with how it’s usually cooked and served than with the vegetable itself. French fries, chips, oven potatoes drenched in oil, or mashed potatoes loaded with butter and cream are all considerably more caloric than a plain boiled potato. On top of that, potatoes are often served in large portions alongside rich sauces or fatty meats, so the calorie count of the whole dish gets pinned on the potato, even though the potato itself contributes a relatively modest share.

Fiber and how filling it is

Boiled potatoes have an interesting quirk: once cooked and cooled, some of their starch converts into what’s called resistant starch — a form that behaves more like dietary fiber in the body and digests more slowly. That’s part of why cold potato salad often feels more filling than the same weight of hot mashed potato. Leaving the skin on also adds a bit of extra fiber and slightly boosts the dish’s overall nutritional value.

Potassium and other nutrients

Beyond carbohydrates, boiled potatoes are a solid source of potassium — a medium potato can actually contain more potassium than a banana of similar weight. They also provide some vitamin C, though a portion is lost during boiling, along with vitamin B6. These nutrients are easy to overlook when the conversation is entirely about calories.

How to cook potatoes to keep them light

To keep potatoes a genuinely low-calorie side, it helps to boil them in their skins (which limits the loss of nutrients and starch into the cooking water) and to dress them with something light — fresh herbs, a squeeze of lemon, a small drizzle of olive oil — rather than a generous pat of butter or a spoonful of mayonnaise. Prepared that way, potatoes are honestly one of the most affordable and filling low-calorie staples you can build a meal around.