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Is Natto Keto-Friendly?

Natto on a kitchen counter

Is Natto Keto-Friendly? This question forms the basis of our exploration into the fascinating world of Natto and the ketogenic diet.

This article dives deep into the carbohydrate content of this unique fermented soybean dish, emphasizing its relative keto-unfriendliness due to its substantial carb count.

We underscore the importance of strict portion control if Natto is to be included in any capacity within a ketogenic meal plan and the potential challenges one might face in maintaining ketosis.Join us as we navigate through the exciting intricacies of balancing the desire to consume Natto and the commitment to a ketogenic lifestyle.


  • Natto, while offering certain health benefits, is not typically considered keto-friendly due to its relatively high carb content.
  • Overconsumption of Natto on a keto diet could potentially disrupt ketosis and lead to symptoms akin to 'keto flu.'
  • With strict portion control and balance with other low-carb foods, Natto can be included in a ketogenic meal plan, though it's a delicate balance.

Is Natto Keto-Friendly?

Let's tackle the pressing question: Is Natto Keto-Friendly? To answer this, I want you to recall the fundamental premise of a ketogenic diet. It's a dietary strategy that primarily relies on fats for energy, moderate protein intake, and significantly restricts carbohydrates. Now, where does Natto fit into this equation?

To start, one must understand the nutritional composition of Natto. It is a nutrient-dense food that boasts a rich profile of proteins, vitamins, and minerals. But when we shift our focus towards the macro-nutrient breakdown, things get a bit more complicated.

A 100-gram serving of Natto contains approximately 7.28 grams of net carbohydrates. Now, if you're adhering strictly to a ketogenic diet, your daily carbohydrate intake might range anywhere from 20 to 50 grams. When you compare these figures, it becomes evident that although Natto isn't extraordinarily high in carbs, it does account for a significant chunk of the daily carb limit for a keto diet follower.

This carb content in Natto doesn't necessarily make it 'anti-keto', but it does call for a mindful approach. When consumed in moderation and portion-controlled servings, Natto can be incorporated into a ketogenic diet. However, going overboard may risk exceeding your carb limit for the day and potentially disrupt the state of ketosis, an essential aspect of a successful ketogenic diet.

Can Natto be Incorporated into a Strict Keto Diet?

Diving deeper into our exploration of Natto and its compatibility with a strict ketogenic diet, one must ponder: Can Natto be squeezed into such a restricted dietary plan?

When considering a strict ketogenic diet, where carb intake can be as low as 20 grams per day, it becomes a bit tricky to include Natto in substantial amounts. As we discussed earlier, a 100-gram serving of Natto contains approximately 7.28 grams of net carbs, which could easily take up more than a third of the strict keto follower's daily carb limit. Even a small overstep in portion size could potentially lead to exceeding the daily carb allowance.

However, this doesn't mean that Natto needs to be permanently crossed off your ketogenic grocery list. Instead, the critical aspect here is portion control. Consuming smaller amounts of Natto, balanced with other low-carb, high-fat foods, can help maintain the state of ketosis.

To ensure you're not unknowingly exceeding your carb limit, a useful strategy can be to meticulously track your daily carb intake. There are many smartphone apps available that make it easy to log your food and keep a close eye on your macros.

That said, it is important to keep in mind that while it is technically possible to incorporate Natto into a strict ketogenic diet, its relatively high carb content does make it challenging. Keeping Natto intake to an occasional treat rather than a staple can be a sensible approach.

Delving into the Carbohydrate Content of Natto

Now, let's take a closer look at the carbohydrate content of Natto to better understand its place in a ketogenic diet.

As we've reiterated, a 100-gram serving of Natto contains approximately 7.28 grams of net carbs. But what exactly does 'net carbs' mean? In the realm of ketogenic diets, net carbs refer to the total carbohydrates in a food, minus the fiber content. This is an important distinction because fiber, while technically a carbohydrate, is not digested by the body and therefore does not impact blood sugar levels or interfere with the state of ketosis.

Now, let's apply this to Natto. Say you decide to incorporate Natto into your keto meal plan and opt for a moderate serving size of 50 grams, about a quarter cup. Doing the math, this portion would contain roughly 3.64 grams of net carbs. If you're aiming for a daily carb limit of 20 grams, this serving size of Natto would take up just over 18% of your daily carbs.

On the other hand, if you were to indulge in a larger 200-gram serving, you'd be consuming around 14.56 grams of net carbs - a significant chunk of, if not surpassing, your daily carb limit on a strict keto diet.

Nutritional Snapshot of Natto

Natto, a traditional Japanese food, comes packed with a rich array of nutrients. A 100g sample serves up 19.4g of protein, making it a significant source of this vital macronutrient. It also includes 11g of total fats and 7.28g of net carbs, offering a balanced nutrient distribution.

In the dietary fiber department, Natto contributes a healthy 5.4g. Dietary fiber is known for its key role in digestive health and could help in maintaining healthy blood sugar levels.

Natto also contains a variety of micronutrients, each with their unique benefits. With 729.0mg of Potassium, it may support heart health and blood pressure regulation, while its 115.0mg of Magnesium might help in nerve function and muscle contraction.

The presence of 217.0mg of Calcium is noteworthy, as it's crucial for bone health. Furthermore, Natto's 8.6mg of Iron can aid in the production of red blood cells.

The food stands out with a high Vitamin K1 content of 23.1ug, which plays a vital role in blood clotting. It also provides 13.0mg of Vitamin C, aiding in immune function and skin health.

Additionally, a mix of B-Vitamins including Thiamin (0.16mg), Riboflavin (0.19mg), and B-6 (0.13mg) contribute to energy production and brain health.

Lastly, Natto offers a balanced blend of 1.59g of saturated, 2.43g of monounsaturated, and 6.21g of polyunsaturated fatty acids, beneficial for heart health.

Nutrient NameAmount and Unit per 100g
Net Carbs 7.28g
Carbohydrate, by difference 12.68g
Fiber, total dietary 5.4g
Total fats 11.0g
Protein 19.4g
Sodium, Na 7.0mg
Potassium, K 729.0mg
Magnesium, Mg 115.0mg
Calcium, Ca 217.0mg
Vitamin B-6 0.13mg
Vitamin C, total ascorbic acid 13.0mg
Vitamin E (alpha-tocopherol) 0.01mg
Vitamin K1 23.1ug
Copper, Cu 0.67mg
Iron, Fe 8.6mg
Phosphorus, P 174.0mg
Selenium, Se 8.8ug
Zinc, Zn 3.03mg
Thiamin 0.16mg
Riboflavin 0.19mg
Folate, total 8.0ug
Choline, total 57.0mg
Calories 211.0kcal
Water 55.02g
Fatty acids, total saturated 1.59g
Fatty acids, total monounsaturated 2.43g
Fatty acids, total polyunsaturated 6.21g
Nutritional data is sourced from the US Department of Agriculture's FoodData Central system. Please see Cast Iron Keto's editorial and research standards for more information.

Health Implications of Natto on a Keto Diet

As we delve into the health implications of consuming Natto while following a ketogenic diet, it's important to understand both the potential benefits and challenges this might pose.

One of the key challenges is maintaining a state of ketosis. Ketosis occurs when the body, deprived of sufficient carbohydrates for energy, starts burning fat instead. The presence of ketones in the body is the hallmark of ketosis and the fundamental goal of a ketogenic diet. Because Natto has a moderate carbohydrate content, overconsumption could potentially disrupt this delicate balance and kick you out of ketosis, hindering your keto progression.

On the other hand, Natto is rich in probiotics, which are beneficial bacteria that contribute to a healthy gut microbiome. A healthy gut can improve digestion, boost the immune system, and even positively affect mood and mental health. Hence, in moderate quantities, Natto can contribute to the overall wellness of an individual on a keto diet.

Furthermore, Natto is a good source of protein and contains vitamin K2, which is known for its role in bone health and heart health. Again, these benefits need to be weighed against the relatively high carb content when considering Natto's place in a ketogenic diet.

However, it is essential to note that every individual's reaction to food is unique and what works for one person might not for another. While some people on a ketogenic diet might be able to incorporate small amounts of Natto without disrupting their state of ketosis, others might find it more difficult.

Importance of Limiting Natto in Your Keto Meal Plan

Balancing your love for Natto and your commitment to a ketogenic lifestyle might seem like a tightrope walk. However, with a few tips and tricks up your sleeve, you can still enjoy Natto in moderation without compromising your state of ketosis.

One crucial strategy is to keep a keen eye on portion control. The high carb content of Natto demands strict quantification. The key is to make Natto a 'guest star' rather than the 'lead role' in your meals. For example, you could add a small spoonful of Natto to your stir-fried veggies or your morning scramble. That way, you get to enjoy its unique flavor without overloading on carbs.

Another way to limit Natto in your meals is to pair it with foods that are high in fat and low in carbs - a guiding principle of the ketogenic diet. For instance, you can make a Natto and avocado salad. The healthy fats in avocado help balance out the carbs from Natto, and the combo makes for a deliciously unique salad.

It's worth noting that exceeding your daily carb limit by overindulging in Natto can result in what's known as the 'keto flu' - a group of symptoms, including headache, fatigue, and irritability, that can occur as your body adapts to a ketogenic state.

Remember, the goal of a ketogenic diet is to keep the body in a state of ketosis, which requires careful management of your macronutrient intake. While Natto can be part of a keto diet, it's crucial to incorporate it mindfully and with moderation.

Keto-Compatible Alternatives for Natto

When it comes to following a ketogenic diet, finding keto-compatible alternatives to higher-carb foods like Natto can be an effective strategy. Here, we'll explore a few substitutes that can help you continue enjoying your meals while staying within your carb limits.

Firstly, consider tempeh. It's a soy-based product like Natto, but it's fermented in a different way and has a different texture. A 100-gram serving of tempeh contains roughly 3.9 grams of net carbs, making it a lower-carb alternative to Natto. Tempeh can be used in a variety of dishes, just like Natto. Try it in a stir-fry with lots of colorful, low-carb veggies for a satisfying keto meal.

Another great alternative is tofu, another soy product. Firm tofu has about 1.9 grams of net carbs per 100 grams, making it an even better option for those on a strict keto diet. Like Natto, tofu can be an excellent source of protein. You can cube and grill tofu for a delicious addition to a salad, or scramble it as a vegan substitute for scrambled eggs in the morning.

Finally, consider mushrooms. While they don’t have the same protein content as Natto, they are low in carbs, making them a nice addition to a keto meal plan. A 100-gram serving of white, raw mushroom contains only 3.3 grams of net carbs. You can sauté them as a side dish, or stuff large caps with a mixture of ground meat and cheese for a satisfying, low-carb meal.

Concluding Thoughts on Natto and Keto

As we've traversed the unique landscape of incorporating Natto into a ketogenic diet, we've encountered various challenges and considerations. While Natto's distinctive flavor and health benefits might make it an appealing addition to your meals, its relatively high carb content poses a significant challenge for strict keto followers.

Maintaining ketosis, the cornerstone of a successful ketogenic diet, becomes notably more difficult with the inclusion of Natto in higher quantities. Exceeding your carb limit, even slightly, can disrupt ketosis, potentially leading to symptoms akin to 'keto flu.' Hence, the importance of meticulous portion control and balancing Natto with other low-carb, high-fat foods becomes paramount.

Although it's challenging to include Natto in a strict ketogenic diet, it's not impossible. Using digital tools to track your daily carb intake can help manage portion sizes better. Alternatively, finding keto-compatible substitutes like tempeh, tofu, or even mushrooms, can offer similar benefits without the carb overload.

One creative solution could be to utilize Natto in a 'flavoring' capacity. For instance, a small amount could be blended into a keto-friendly dressing or sauce, providing its distinctive taste without significantly impacting your carb count.

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Cast Iron Keto's Editorial and Research Standards

Certain rare or exotic food items may not have nutritional profiles in the FoodData Central database. If an exact match is not found in the FoodData Central database, then, the Cast Iron Keto team utilizes a three-prong approach to provide readers with the closest relevant nutritional data, where possible.

First, in the event that nutritional profiles for a rare or exotic food item is not available in the FoodData Central database, we investigate alternative names for that particular food item and use that data, when possible. Second, in cases where no alternate names exist, Cast Iron Keto will use nutritional data for a close relative or similar food item. Finally, if no close relatives or similar items exist, we refrain from publishing nutrient data tables.

When making dietary or health decisions based on FoodData Central's data, we suggest readers consult with a nutritionist or other health experts, particularly if the food in question has a significant role in your diet or if you are using the food item to treat any health disorder(s).

Furthermore, it is important to note that even if a close relative or similar item is used to approximate the nutritional data, different food items can have varying levels of nutrients due to factors such as soil quality, farming practices, and regional differences.


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Frequently Asked Questions

Yes, you can, but in very limited quantities due to its high carb content. Strict portion control is crucial to prevent disrupting ketosis.

Yes, overindulgence in Natto can exceed your daily carb limit, which can disrupt ketosis and lead to symptoms similar to the 'keto flu.'