The Ikigai Diet

Can you mix Bacillus subtilis with other bacteria to make yogurt? Most people assume the answer is yes — but today I explain why it is almost always no, with one powerful exception. In this Fermentation Q&A, I answer the question I receive most often about natto yogurt: Can you mix Bacillus subtilis with other bacterial strains? I start by explaining why combining Bacillus subtilis with Koji — two of Japan's most powerful fermentation cultures — is actually counterproductive. In fact, sake brewers in Japan are not even allowed to eat natto, that is how dominant Bacillus subtilis is in a fermentation environment. But there is one exception: Bifidobacteria. But only if you apply one trick.


📌 What you will learn:
Why Bacillus subtilis overpowers most other bacteria
Why Bacillus subtilis and Koji are incompatible
How you should separate fermentation jars for Koji, yogurt, and natto
Why Bifidobacteria is the one exception
The special trick that enables the co-fermentation of natto bacteria and bifidobacteria
How this yogurt supports butyrate production and gut microbiome health

Can You Mix Natto with Other Yogurt Strains? Fermentation Q&A
https://youtu.be/NIftQ3MmRv0

3 days ago | [YT] | 8

The Ikigai Diet

If you're over 50 and eating natto for protein, you might be getting only half the benefit. Here's why: regular natto beans alone don't give you a complete amino acid profile. But when you ferment soybeans with brown rice — something most people have never heard of — the protease from Bacillus subtilis pre-digests the rice protein alongside the soy protein, creating a synergistic complete protein that your muscles can absorb far more efficiently. I'm Sachiaki Takumiya, the author of Natto Unleashed, and in this video I'll show you exactly how to make brown rice natto at home using wild plants.

Homemade Natto: This Recipe Builds Muscle 2X vs Regular Natto
https://youtu.be/61dV-dF5fEc

1 week ago | [YT] | 12

The Ikigai Diet

Natto is one of Japan's most powerful fermented foods — but its amino acids are incomplete. It's rich in lysine but missing methionine. Brown rice has the exact opposite profile. When you ferment them together, the protease pre-digests both into a complete protein your body absorbs more easily than just mixing rice and beans in a bowl.


But that's just benefit #1. Brown rice natto also gives you the fiber and probiotics that animal protein can't offer, it feeds your butyrate-producing "longevity bacteria" in ways regular natto doesn't, and eating it cold creates resistant starch that feeds those same bacteria even further.

In this video, I walk through all four benefits — and explain why this one combination may be the most underrated food for anyone over 60.

Brown Rice Natto: Japan's Complete Protein Hack
https://youtu.be/mCFpmVTiolg

1 week ago | [YT] | 8

The Ikigai Diet

This video explores how specific Japanese foods can aid in visceral fat reduction by rebuilding mitochondria and activating the AMPK pathway through butyrate production. We discuss activities like Zone 2 cardio that contribute to fat loss, contrasting them with behaviors that increase belly fat. This approach focuses on metabolic health for healthy aging and longevity.

This Japanese Food Destroys Visceral Fat by Rebuilding Your Mitochondria
https://youtu.be/RjO7ylaCi4U

2 weeks ago | [YT] | 10

The Ikigai Diet

Both are powerful — but they're not the same. Discover which form of natto is right for YOUR health goal, and when to use each one. Most people think natto is natto. But whole natto beans and natto yogurt (nattogurt) deliver their natto benefits in very different ways — and choosing the wrong one for your goal could mean leaving results on the table. In this video, I break down exactly how they differ, and more importantly, how to match the right one to your body.

What you'll learn:
Why nattogurt is the "Liquid Warrior" for rapid muscle recovery and gentle digestion
Why whole natto beans are the "Fiber King" for autophagy, satiety, and maximum spermidine
Which one delivers nattokinase more efficiently — and why it matters for your cardiovascular health
The best time to eat each one for maximum natto health benefits

This isn't about which is better. Both belong in your Japanese longevity toolkit — the key is knowing WHEN to reach for each one.

Whole Natto or Natto Yogurt? Match the Right One to Your Body
https://youtu.be/yCIrvC7wii8

3 weeks ago | [YT] | 10

The Ikigai Diet

Can you make natto yogurt using dairy milk? One of my viewers thought so — and they had a good reason. They'd heard that Dr. William Davis, author of Super Gut, had successfully fermented dairy milk using Bacillus subtilis. So naturally, they wondered: if it works for soy milk, why not dairy? I decided to test it. I fermented dairy milk with mugwort plants at 42°C for 24 hours — the exact same method I used to successfully make yogurt from soy milk. Same bacterium. Same temperature. Same duration.The result? I'm sharing it in this video. 👇And more importantly, I'm comparing my method side by side with Dr. Davis's approach — because the differences are revealing. They tell us something fundamental about Bacillus subtilis, about soybeans, and about why Japan has been fermenting with this bacterium for centuries.
Can Bacillus Subtilis Ferment Dairy Milk into Yogurt?
https://youtu.be/I0dz0st9QxE

4 weeks ago | [YT] | 7

The Ikigai Diet

Can you skip the natto beans entirely and still make probiotic yogurt from scratch? A viewer's question sent me straight to the kitchen. After sharing how I make natto yogurt using natto beans as a starter, one viewer wondered — since I usually make natto from wild plants, could I make natto yogurt the same way? It's a brilliant question, and in this video, I put it to the test. But before I reveal the result, I want to make sure everyone is on the same page — especially if you're new to this channel.

Here's what we cover:
🌿 Can you actually make natto from wild plants? The science behind why Bacillus subtilis lives on wild plants — and why that matters for probiotic yogurt
🌱 Which wild plants are best suited for natto making
⚖️ Wild plants vs. natto beans: A full comparison of three starters — store-bought natto beans, manufactured starter spores, and wild plants — including the advantages and disadvantages of each
🥣 The mugwort experiment: Can wild plants ferment soy milk into a thick, tangy probiotic yogurt without a single natto bean?

Why does this matter? Not everyone can get hold of natto or soybeans. But soy milk is sold almost everywhere — and if you have herbs growing in your garden, you now have everything you need to start your own probiotic yogurt practice at home. This is the Ikigai Diet philosophy: working with what nature provides, rooted in Japan's oldest fermentation traditions.

Can You Make Probiotic Yogurt from Wild Plants without the Natto Beans?
https://youtu.be/dchB2UV2TaE

1 month ago | [YT] | 7

The Ikigai Diet

A viewer asked a question I couldn't ignore — and it sent me straight to the kitchen to run a proper experiment. After sharing my natto yogurt results, one thoughtful viewer wondered: Is the coagulation really caused by live Bacillus subtilis? Or could it simply be preexisting protease enzymes on the surface of the natto starter doing all the work — no live bacteria required? It was exactly the kind of question that deserved a real answer. Not a guess. An experiment.The 60°C Test:


The logic was elegant in its simplicity:
Heat the soy milk to 60°C before adding the natto starter
At this temperature, natto bacteria become dormant — but protease enzymes remain fully active
If soy milk still coagulates → protease is responsible
If it doesn't → live natto bacteria are doing the work


So I ran the test.

Viewer Challenged My Natto Yogurt Science — Here's What the 60°C Test Revealed
https://youtu.be/0mqymbnX2Z8

1 month ago | [YT] | 5

The Ikigai Diet

What if the best probiotic yogurt you'll ever make uses just two ingredients — soy milk and a few natto beans? In this video, I'll show you how to make Natto Yogurt: a fermented soy drink powered by Bacillus subtilis, the bacteria behind natto's legendary protease — and why it delivers even more bioavailable protein than soy milk amazake. Most people discover natto for its nattokinase benefits. But here's what very few people talk about: natto bacteria produce a protease significantly stronger than koji. That means the soy protein in your soy milk gets broken down even further — into free amino acids your body can absorb almost immediately. This is why I upgraded my soy milk amazake ritual with natto yogurt. In Japan's longest-lived regions — Shiga, Nagano, and Okinawa — fermented foods aren't a trend. They're a daily habit passed down for centuries. Natto yogurt is my way of combining that wisdom with modern nutritional science to support gut health, protein absorption, and longevity.

🧬 What you'll learn in this video:

✅ Why natto bacteria produce a stronger protease than koji — and what that means for your muscles
✅ How natto yogurt compares to soy milk amazake for bioavailable protein
✅ The simple 2-ingredient recipe (no special equipment, ready in 24 hours)
✅ How to combine natto yogurt with other foods to optimize your protein bioavailability


Whether you're already making natto or just starting to explore fermented foods for longevity, natto yogurt is the next level upgrade.

Forget Soy Milk Amazake — Natto Yogurt Has Even More Bioavailable Protein
https://youtu.be/XNoOiMKT5Qw

1 month ago | [YT] | 10

The Ikigai Diet

After making brown rice Amazake and learning that protease in koji breaks down the protein in brown rice into amino acids, I came up with the idea of making Amazake with soy milk to increase the protein content. This is what happened.

Most People Waste 40% of Their Protein — Japan's Soy Milk Amazake Fixes This
https://youtu.be/wgHUWdA4djQ

1 month ago | [YT] | 6