How Many Calories Are In Japanese Sweet Potato? | Fast, Clear Facts

What Counts As A Serving?

Portion sizes swing calories more than anything. A palm-size piece is often 120–150 g once cooked. A larger stall-style “yaki-imo” can hit 250 g. Cooked weight matters, so weigh after roasting or steaming.

Table: Calories By Form And Common Portions

This table uses Japan’s official food composition data for sweet potato. The same tuber weighs less after dry heat, so the calorie number per 100 g rises when baked.

Form	Typical Serving	Calories
Raw, peeled	100 g	126 kcal
Raw, peeled	150 g	189 kcal
Steamed, peeled	100 g	131 kcal
Steamed, peeled	150 g	196 kcal
Baked/roasted, peeled	100 g	151 kcal
Baked/roasted, peeled	150 g	227 kcal
Baked “yaki-imo”	200 g	302 kcal
Baked “yaki-imo”	250 g	378 kcal

Snacks fit better once you set your daily calorie needs.

Calories In A Japanese Sweet Potato By Size

Here’s a quick way to eyeball it. Slice off a chunk that matches your plan for the day. For tighter tracking, weigh the cooked piece and use the baked or steamed line below.

Why Baked Reads “Higher” Than Raw

Roasting drives off water, so each gram holds a bit more energy. It’s the same food, just more concentrated. Japan’s database lists raw at 126 kcal per 100 g and baked at 151 kcal per 100 g. You’ll see a similar bump with steaming, but it’s smaller because moisture stays inside.

Reliable Numbers You Can Trust

The figures here come from the Japanese Standard Tables of Food Composition (Eighth edition supplements). You can check the entries yourself: raw without skin and baked without skin are both listed with energy per 100 g. Link to the specific entries sits below in the references and again in the card above.

How Cooking Method Changes Energy

Raw (Prep Stage)

Raw peeled tubers sit at 126 kcal per 100 g. That’s the baseline before heat. Once you steam or roast, water loss shifts the math.

Steamed (Soft And Sweet)

Steaming comes in at 131 kcal per 100 g. Texture stays moist, and the calorie number nudges up because a little water leaves the cells.

Roasted/Baked (Street-Style “Yaki-Imo”)

Dry heat pushes the count to about 151 kcal per 100 g. Caramel notes intensify, and the flesh gets denser. If you buy a large roasted piece from a cart, weigh it when you can and apply the baked line to estimate the total.

Skin, Toppings, And Add-Ons

Skin On Or Off

The database values above use “without skin.” Eating the skin won’t move calories much, but it adds fiber and minerals. If your scale includes skin, your estimate stays close enough for daily tracking.

Butter, Honey, Or Nothing?

Plain steamed or roasted keeps the numbers clean. A teaspoon of butter or honey adds energy fast. If you’re shooting for a lean snack, stick to cinnamon, sesame, or a pinch of salt.

Carbs, Fiber, And Vitamins—At A Glance

Carbohydrates

Most of the energy comes from starches that gel on heat. That’s why roasted pieces feel sweeter even when sugar grams don’t skyrocket.

Fiber

You’ll get a few grams per 100 g cooked. That helps with fullness, especially when you keep the skin.

Vitamin C And B-Group

Steaming preserves more vitamin C than high heat, but both methods keep useful B-group levels. Pair with a protein source at meals for a balanced plate.

Smart Ways To Use It

As A Snack

Cut a 100–120 g section, let it cool, and stash it for later. It travels well and doesn’t need extras.

As A Meal Side

Plate 150–200 g next to eggs, chicken, tofu, or fish. That portion lands in the 200–300 kcal range depending on cooking method.

As Training Fuel

Go 200–300 g roasted for long runs or rides. Sprinkle salt after sweaty sessions to replace what you lost.

Portion Math You Can Use

Weigh once, match the weight to the line, and you’re done. Measurements below round to whole numbers for quick logging.

Table: Weight-To-Calories Quick Chart

Cooked Weight	Baked Calories	Steamed Calories
80 g	121 kcal	105 kcal
100 g	151 kcal	131 kcal
120 g	181 kcal	157 kcal
150 g	227 kcal	197 kcal
200 g	302 kcal	262 kcal
250 g	378 kcal	328 kcal

How To Get Precise At Home

Step 1: Pick The Method First

Choose steam or roast and stick with it for the week. That keeps your tracking consistent.

Step 2: Weigh After Cooking

Moisture loss changes the weight. Put the finished piece on a kitchen scale and log that number, not the raw weight.

Step 3: Match To The Right Line

Use the baked numbers for oven or air-fryer batches. Use the steamed numbers for basket or microwave steam.

Common Questions (Short And Practical)

Are Japanese Types Higher Than Orange?

They tend to be denser when roasted, so the per-100 g energy often sits higher. That’s why the official baked entry lands at 151 kcal per 100 g, while some orange types tracked in U.S. tables read lower per 100 g when baked.

Do Store-Bought Roasted Pieces Differ?

Yes—water content varies with time and temperature on the hot shelf. The safest way is to weigh the piece after purchase and use the baked line.

References You Can Check

Japan’s Standard Tables list energy for sweet potato in raw, steamed, and baked states. The entries for raw (without skin) and baked (without skin) give the exact per-100 g numbers used throughout this page. You’ll find them on the Ministry’s database pages, linked in the card above and here in the body:

• Sweet potato, raw, without skin (100 g)
• Sweet potato, baked, without skin (100 g)

Final Bite

If you want a steady carb that scales to your day, Japanese sweet potato makes it easy: weigh the cooked portion and match the chart. Want a step-by-step habit to pair with it? Try our walking for health.