Does Konnyaku Have Calories? The Surprising Truth for Dieters

October 25, 2025 •

3 min read

Made from the starchy root of the konjac plant, a single 100g serving of konnyaku contains only about 7-10 calories. This extremely low-calorie content is a major reason for its popularity in Japan and with dieters worldwide, prompting many to ask: does konnyaku have calories at all?

Quick Summary

Konnyaku, derived from the konjac plant, is a staple in many Japanese dishes and is prized for being incredibly low in calories and rich in soluble fiber. Its primary component, glucomannan, is indigestible, resulting in a minimal caloric load and zero net carbohydrates.

Key Points

Low Calorie: Konnyaku, made from the konjac plant's glucomannan fiber, contains very few calories (approx. 7-10 kcal per 100g) that are not absorbed by the human body.
High Fiber: Its high content of glucomannan, a soluble fiber, promotes a feeling of fullness and aids digestion.
Nutrient Absorption: The fiber can slow nutrient absorption, including sugar, which helps regulate blood glucose levels.
Versatile Ingredient: Konnyaku is flavorless on its own but absorbs the flavors of accompanying dishes, making it a great low-carb alternative to pasta and rice.
Safe Preparation: It must be consumed with plenty of water and chewed thoroughly to prevent choking and digestive discomfort.
Not a Complete Food: Konnyaku lacks substantial protein, vitamins, and minerals, so it should be consumed as part of a balanced diet.
Side Effects: Overconsumption can lead to bloating, gas, and other gastrointestinal issues due to its high fiber.

What is Konnyaku, and Why is it so Low in Calories?

Konnyaku, often made into a block or noodles (shirataki), is a traditional Japanese food with a chewy, jelly-like texture. The reason for its near-zero calorie count lies in its unique composition. The primary ingredient is glucomannan, a type of soluble dietary fiber extracted from the root of the konjac plant. Glucomannan passes through the human digestive system largely unabsorbed, as the body lacks the enzymes to break it down for energy. This makes it a fantastic tool for weight management.

The Science Behind Glucomannan and Calorie Count

When consumed, glucomannan absorbs a significant amount of water, expanding in the stomach. This creates a feeling of fullness, or satiety, which can help reduce overall food intake. While the fiber itself technically contains calories, these are not accessible to the body, making the food functionally calorie-free. This indigestible nature is why products like shirataki noodles are marketed as having zero net carbs and almost no calories.

Health Benefits Beyond a Low-Calorie Count

Konnyaku's high fiber content offers numerous health advantages beyond simple weight control:

Improved Digestion: The soluble fiber aids in promoting regular bowel movements and can help relieve constipation.
Blood Sugar Regulation: Glucomannan has been shown to help stabilize blood sugar levels by slowing down the absorption of glucose. This is particularly beneficial for individuals managing diabetes.
Lowered Cholesterol: The fiber in konnyaku can also help reduce bad (LDL) cholesterol levels.
Gut Health: As a prebiotic, glucomannan can promote the growth of beneficial bacteria in the gut microbiome.
Skin Health: Some studies suggest that konjac may contain ceramides, which help maintain skin hydration and health.

Preparing and Cooking with Konnyaku

Before cooking, konnyaku blocks or noodles should be rinsed thoroughly to remove the slightly fishy odor from the packaging liquid. A quick boil or blanching can further neutralize this smell. Because konnyaku has very little flavor on its own, it excels at absorbing the flavors of the sauces and broths it's cooked in. This makes it a versatile ingredient for a variety of dishes, from traditional Japanese cuisine like oden and sukiyaki to modern, low-carb pasta alternatives.

Common Uses of Konnyaku

In Traditional Dishes: Used in classic Japanese stews and simmered dishes like oden or nishime.
As a Noodle Substitute: Shirataki noodles are a popular pasta and rice alternative for keto and low-carb diets.
In Stir-fries: The chewy texture adds a unique element to stir-fried vegetables.

Konnyaku vs. Traditional Pasta: A Nutritional Comparison

To highlight the difference, here is a comparison of konnyaku noodles (shirataki) versus traditional wheat pasta, per 100g cooked portion:


Feature	Konnyaku (Shirataki) Noodles	Traditional Wheat Pasta
Calories	~7-10 kcal	~150-160 kcal
Carbohydrates	Minimal (often considered 0 net carbs)	High (~30-35g)
Fiber	High (several grams)	Low (1-2g)
Protein	Negligible	Moderate (5-6g)
Primary Benefit	Weight management, fiber intake	Energy source

Potential Downsides and Safe Consumption

Despite its many benefits, konnyaku requires careful consumption. The expanding nature of glucomannan can pose a choking hazard, especially with supplements or jelly candies, which has led to regulations in some countries. It is crucial to chew konnyaku products thoroughly and consume them with plenty of water. Some individuals may also experience digestive discomfort, such as bloating, gas, or diarrhea, due to the high fiber content. Starting with small portions and ensuring adequate hydration is recommended.

Conclusion: A Calorie-Conscious Choice

So, does konnyaku have calories? The answer is technically yes, but functionally no, as the calories are from a type of fiber that the body cannot digest. For those monitoring their calorie and carbohydrate intake, konnyaku represents an excellent dietary option. Its ability to create satiety while adding minimal caloric value makes it a powerful tool for weight management. By understanding its unique properties and preparing it correctly, this versatile Japanese ingredient can become a valuable addition to many health-conscious meal plans.

How to Use Konnyaku Safely

To minimize risks and maximize benefits, always follow these tips when preparing konnyaku:

Rinse and Cook Thoroughly: Always rinse konnyaku products before cooking and ensure they are well-prepared in dishes.
Increase Water Intake: Due to its high absorbency, consume konnyaku with plenty of fluids to prevent dehydration and aid digestion.
Start Slowly: If you are new to high-fiber foods, introduce konnyaku in small amounts to allow your digestive system to adapt.
Chew Properly: Especially for blocks or jelly forms, chew each piece well before swallowing to reduce the choking risk.

Frequently Asked Questions

A 100g serving of konnyaku contains approximately 7-10 calories. The human body cannot digest the glucomannan fiber, so the effective calorie count is nearly zero.

Yes, konnyaku can aid in weight loss due to its extremely low-calorie count and high fiber content. The glucomannan fiber expands in the stomach, promoting satiety and helping to reduce overall food intake.

The primary ingredient is glucomannan, a soluble dietary fiber extracted from the root of the konjac plant.

Shirataki noodles are a form of konnyaku, typically shaped into thin, translucent noodles. They are essentially the same product, just in a different form.

Yes, konnyaku is an excellent choice for a keto diet because it has virtually zero net carbohydrates and is extremely low in calories.

Some people may experience digestive discomfort such as bloating, gas, or diarrhea from the high fiber content. Adequate hydration and proper chewing are essential for safe consumption.

Before cooking, konnyaku should be rinsed thoroughly under cold water to remove the packaging liquid's odor. Blanching it in boiling water for a few minutes can also help neutralize the smell.