The Truth About Overnight Oats

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What's wrong with overnight oats, and how to prepare them in the most nutritious way. Recipe included! By Marisa Moon of My Longevity Kitchen

Somebody got this trend all wrong. 

Well, not ALL wrong…but they messed up the only step in the recipe!  We shouldn’t be soaking our overnight oats in the refrigerator, we should be soaking them with warm water, at room temperature—or even warmer.  And would you believe that cooking the oats afterwards actually makes them even MORE nutritious.  This is not a food you want to eat raw.  Let me break down the basics for you…

Our ancestors ate whole grains after soaking them or fermenting them.  Over time they figured out that this was how grains needed to be prepared—in order to avoid illness.  It was probably thanks to serendipity that they figured this out back then because there weren’t any refrigerators…food was just left out.  But as generations passed, and food culture diminished, we have been hastily preparing our grains…and we’ve even gone as far as thinking they are best uncooked!  This is flat out wrong.  

Did you know that the oatmeal box, back in the day, used to say “soak overnight” in the directions?  What happened to that?

You see, all grains contain something called “phytic acid”—or phytates—in the outer layer or bran, and oats contain more phytates than almost any other grain.  So, if this phytic acid is untreated, it will combine with important minerals in our body and block their absorption.  I’m talking about calcium, magnesium, iron, zinc, and copper.  We need these minerals, and our food supply is providing less and less of them because of modern farming methods.  We should take every precaution to protect the minerals that are still available to us.  Regular consumption of improperly prepared grains (also legumes, and nuts) can lead to mineral deficiencies, leaky gut, irritable bowel syndrome, bone loss, food allergies, and even mental illness.  

Go Raw brand chart why to soak/sprout seeds
Illustration by Go Raw and

So what’s the proper way to prepare these grains? 

The process is simple really.  All we need to do is soak the whole grains overnight at room temperature, or even warmer!  It helps tremendously if you add an acid starter like liquid whey, kefir, yogurt, or even lemon juice.  Allow the natural enzymes and other helpful organisms to begin fermenting the grains, for 7-24 hours, and this will neutralize a large portion of the phytic acid.  Soaking in warm, acidic or cultured water not only gets rid of this mineral-blocking substance, but it also releases all of the vitamins in grains, and encourages more healthy digestion by partially breaking down some of the proteins (like gluten).  Win Win, all around!  Finish your oatmeal by cooking for a quick 5-10 minutes (more on that in the recipe at the end of this post). 

The Truth About Overnight Oats
Pouring liquid whey into my soaking oats

Spread the word to those we care about.  

Oatmeal is one of those things that people eat habitually…every single morning.  That’s why it’s important to spread the word.  Although I do not usually consume oatmeal, or most grains, I felt the need to focus on this recipe because many of my closest friends and family are enjoying oatmeal on a regular basis.  My goal with My Longevity Kitchen is to help explain how we can maximize the nutrients in our food, and minimize toxins.  And my passion lies in the ways of our ancestors, and their time-honored traditional cooking methods.  Oatmeal can be nutritious, or quite the opposite.  I hope you’ve learned a thing or two on how to make it truly nourishing.   Here are some more tips for you, and the recipe!

A nourishing recipe for properly prepared overnight oats with cinnamon, banana, and pecans. By Marisa Moon of My Longevity Kitchen

More Tips on Oats:

  • Always buy ORGANIC Oats and any gluten-containing grains. This is imperative because science now shows that when the weed killer named Glyphosate is in the presence of Gluten (in our digestive tract) it passes through the intestinal wall. This will likely lead to immune responses, irritating symptoms, leaky gut, or a gluten intolerance. Take caution and only buy organic gluten grains. 
  • Always eat your oats and grains with a healthy fat like grass-fed butter, grass-fed cream, coconut milk, or coconut oil.  The fats are necessary for us to absorb the fat-soluble vitamins in grains.  
  • Never buy your cracked or rolled oats in the bulk bin.  You want them in a sealed package so the oils don’t go rancid and cause free radicals in the body. 
  • It is a tremendous help to use a probiotic-rich liquid like whey (the liquid on top of your plain yogurt), buttermilk, whole-milk plain yogurt, whole-milk kefir, coconut kefir, when soaking your oats.  This helps break down the phytic acid the most (and it also inhibits any harmful bacteria from growing).  If you are completely against dairy, or don’t have any on hand, then you can try another acidic medium like lemon or apple cider vinegar, but you probably should be adding another gluten-free grain like buckwheat groats (not actually a grain, but it is Gluten Free) because it helps to break down phytic acid in those stubborn oats (more on this here).  These soaking methods will encourage the beneficial bacteria, enzymatic release, and proper breakdown of those stingy phytates in grains.  That is why you’ll see this recipe recommends adding up to 2 Tablespoons of such liquid while soaking.   

More about Liquid Whey:

  • “Acid” Whey, a byproduct from making unripened fresh cheeses, has been prescribed for an assortment of human ailments, even by Hippocrates himself in 460 BC.   Cool, huh?  Throughout the middle ages doctors continued to prescribe whey so much that “whey houses” were popping up all over western Europe.  They treated everything from arthritis to anemia, with whey.  Whoa.  
  • Whey supplies lactobacilli, which are important probiotics.  The homemade stuff has many uses including making facto-fermented vegetables like when pickling and making sauerkraut.  It’s also used in condiments or beverages like kefir and cultured mayonnaise, or when soaking and sprouting nuts or grains, like we are here.  The lactic acid in the whey helps break down the stubborn grains.  Traditional uses even include adding whey to sauces and soups; if you don’t cook/reheat the soup after adding, you’ll get the enzymatic benefits which help with digestion and nutrient availability.  
Whey making with muslin
Making Whey. Photo: Andy Ciordia

Make Your Own Whey (Easily):

  1. Get thee to the grocery store for some quality, plain, full fat yogurt.  Seek out brands that have active cultures (the label should say somewhere that it has lactobacillus or “live active cultures”), are organic, made from the milk of pasture-raised cow, goat, or sheep; and non-homogenized (this means there’s less processing and the cream rises to the top— like it’s supposed to).  
  2. Line a mesh strainer with a thin dish towel, or muslin if you’re lucky enough to have it (or 4+ layers cheesecloth should work), and place it over a bowl to rest.  Add the plain yogurt and let it sit at room temperature for 5 hours.  You’ll notice the (acid) whey is dripping into the bowl, like the photo above.  
  3. Next, gently gather the ends of your cloth, without squeezing, and tie it around a wooden spoon so it can hang over the top of the bowl and drip even more whey (you might use a pitcher instead of the bowl at this point because the sack will hang too low).  Usually you’d just leave it like this overnight to get the most whey out of it, but you can stop any time.  I’ve tied the cloth on a high oven rack before and left it in the oven to drip into a bowl on the lower rack.  Some people tie the sack on the faucet head and let it drip into a bowl in the sink.  Now you have plenty of whey which will keep in a glass jar, in the fridge, for 6 months.  Bonus: the cheese left behind is basically like cream cheese, perfect for dips or spreads, and will keep for a month when refrigerated.  

Want to learn more about phytic acid, traditional methods, and soaking grains?  

My biggest inspiration thus far is the cookbook called Nourishing Traditions.  You should check it out if this topic of traditional food preparations interests you.

Tons of info here on phytic acid and soaking grains.

“The Whey Prescription”, A Summary

Scientific Studies:

The importance of lactic acid bacteria for phytate degradation during cereal dough fermentation.

Effects of soaking, germination and fermentation on phytic acid, total and in vitro soluble zinc in brown rice

Degradation of phytic acid in cereal porridges improves iron absorption by human subjects

Nourishing Overnight Oats with Cinnamon, Banana, and Pecans
Serves 2
Traditionally prepared, overnight oats topped with healthy fats and crunchy pecans. With a thoughtful soaking session, and the proper ingredients, this porridge-style oatmeal can be a healthful addition to your family table. The combination of salty and sweet reminds me of the hot breakfast cereal I ate growing up.
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Prep Time
24 hr
Cook Time
10 min
Prep Time
24 hr
Cook Time
10 min
  1. 1 Cup gluten-free ROLLED OATS
  3. 2 Tablespoons ACID WHEY or 1.5 teaspoons apple cider vinegar (see notes for info and substitutions)
  4. 1/2 teaspoon FINE SEA SALT
  5. 2 Tablespoons of Unsalted GRASS-FED BUTTER (or coconut cream, coconut oil)
  6. 1/2 Cup crushed PECANS
  7. 1 BANANA
  1. Pour 1 cup of OATS in a glass bowl, and stir in 1 cup of warm FILTERED WATER, and 2 Tablespoons of acid WHEY (or 1.5 teaspoons of apple cider vinegar). Cover loosely, and leave overnight in the oven or a cabinet. Allow to soak for at least 7 hours and up to 24 hours.
  2. Optional Step (for changes in flavor): Pour soaked oats into a mesh strainer and rinse with water.
  3. Pour your soaked oats into a non-stick pot, with 1 cup of FILTERED WATER, and 1/2 teaspoon of FINE SEA SALT. Turn heat to high and bring to a boil. Once boiling, COVER and turn heat to LOW to finish cooking for 5 more minutes.
  4. Portion into two bowls (or save some for later, in the refrigerator, for up to a week). Top each portion with 1 Tablespoon of unsalted GRASS-FED BUTTER (or coconut cream/oil), 1/2 sliced banana, 1/4 cup crushed pecans, and plenty of cinnamon. See notes for recommended sweeteners.
  1. WHEY: This is the liquid on top of plain, full fat yogurt. Large tubs of yogurt have about 2 Tablespoons of whey floating on top which you can just pour out and use for this recipe. See the info in this post on how to make your own whey and store it for 6 months! You may also use Kefir or Buttermilk, but the nutritional benefits are superior with whey. You can even just use the plain yogurt. A good non-dairy alternative that is also convenient is Lemon Juice or Apple Cider Vinegar.
  2. SWEETENERS: I think the banana slices are enough for a sweetener. If you need more sweetness, try sprinkling some erythritol, munk fruit sweetener, or xylitol on your oatmeal. We do love the addition of raw honey or maple syrup, but prefer not to use these sugary toppings since the oatmeal is already high in carbohydrates.
Adapted from Nourishing Traditions
Adapted from Nourishing Traditions
My Longevity Kitchen


54 Responses

  1. I read that phytic acid can lead to dental carries, due to the acid blocking essential nutrients. Have you ever read anything like that? My family and I recently got into uncooked overnight oats because it’s so easy to grab and go. But you are saying I should soak 1 cup of organic rolled oats w/filtered warm water, add 2 TB of ACV, lemon juice or kefir cover overnight in the refrigerator? In the morning do I have to rinse the oats or can I just place the soaked oats in a pot to be cooked? Thank you for this insightful article. I want to ensure my family is absorbing all of the important nutrients.

  2. Thank you for your thoughtful and prompt reply Marisa, i really appreciate that.
    My method is as follows…. I blitz a mixture of nuts and seeds in a coffee grinder, i then add one part of this mix to four parts blitzed rolled oats, i then pour over hot milk, when cool i add three tablespoons of kefir or active yoghurt and leave loosely covered overnight. The reason i blitz the nuts and oats is because it hugely increases the surface area of the mixture which provides the perfect requirements for the kefir to produce the maximum amount of good bacteria in the gut. add some fruit if desired in the morning.


    1. Interesting idea. It also sounds so delicious. I do have a couple of concerns that may or may not be warranted. When we heat milk to the point that it is hot, we likely will denature (disfigure) the proteins which may eventually cause some harm in our GI tract. Secondly, nuts and oats have very fragile fats that oxidize and go rancid easily. Grinding them in advance would almost ensure these rancid fats. If you grind them fresh (including the oats) and mix them with the culture, they might be okay if loosely covered—but I am not sure! Sorry to rain on the delicious parade, but i thought I would share with you my initial thoughts.

      Marisa Moon

  3. Hi Marisa, would it be ok to cook the rolled oats in milk..allow to cool, then add the kefir and ferment overnight at room temperature, then eat in the morning, thus keeping the kefir good bacteria without killing them in the cooking process?

    1. That’s a good question. I would imagine once you cook the oats then they are “sterilized” and won’t encourage bacterial fermentation. But maybe I am wrong with that guess because it is still a starchy food—which would provide food for the bacteria. Hmmmm, I’m sorry I don’t really know.

      Remember, there are many benefits to using probiotic-rich foods besides the actual live cultures making it into our GI tract. The probiotic bacteria multiply the vitamins available in the food you are fermenting, and they make it easier to digest. There are probably way more benefits that science hasn’t been able to identify yet. So don’t be afraid to cook it after a good cultured soak. You can always add a bit more kefir onto your oatmeal when you eat it (after cooking).

  4. Hi, can I just add a scoop of yogurt instead of straining for whey if I’m in a rush….would this work the same if I soak it 8-12 hrs? Is there an easier way to get whey? If you wanted to make this every day for breakfast you’d need to strain a lot of yogurt?

    1. You can use yogurt instead of just the whey if you’re in a rush. And check out the end of this very blog post for tips on how to easily make your own whey. If you like the yogurt in your oatmeal, then go for it since it’s more convenient.

  5. Hello!

    Do I have to cook the soaked oatmeal? Can I add kefir in the morning, before eating, and still get the required benefits of the oatmeal?

    1. Hi Senka,

      It’s a pretty important step to cook the oatmeal because it breaks down the grain even further, and it only takes about 5 minutes. The soaking process is also important, offering different benefits from the cooking. If you add kefir to your oatmeal before eating, it would have to be left for at least 7 hours at room temperature to get any significant reduction in the phytic acid. The whole process seems lengthy, but it’s very hands-off and simple. I hope you will give it a try.

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  7. Hello MLK, can unstabilized rolled oats (I believe less processed) be used in the same way as you have previously suggested.
    Yours faithfully,

  8. Hello, I have a couple of packets of raw sprouted oats that have not been steamed. I can’t eat gluten and although I know you said heating the oats is pretty much essential I can’t always do that as sometimes I have no access to hot water or heat…camping, festivals etc… I am wondering if there could be any bad bacteria contamination issues if I eat raw sprouted oats that have only been soaked in yogurt and/or milk but not heated? Thanks!

    1. Hi Becca,

      I suggest that you always use a probiotic/yogurt/whey liquid to soak the oats if you’re not cooking them. Are you soaking them in a cooler with ice or out in room temperature? Ideally it would be covered loosely so the bacteria can breathe as it ferments, and at room temperature or warmer. You’d have to cover with a towel and wrap it around the bowl with a rubber band or tight string to keep pests out.

      Milk doesn’t sound like a good idea without the probiotic cultures to help the good bacteria thrive (versus the bad bacteria).

      Does this answer your question? Thanks for reading.

      1. Yes thank you! I will go for a non cooled soak with a probiotic as you suggest for 8 to 12 hours and wrap it as you described, that sounds great. Being gluten free it is great to have these oats as an option. I was just slightly wary that if the oats had not been steamed to kill any unwanted bacteria on them then the soaking process could encourage some naturally occurring bad bacteria rather than the good guys but if the probiotics should steer things in the right direction that makes sense. Thanks for the speedy response.

  9. Really good article! One question though: you seem to suggest in your article that adding a cultured medium such as kefir will cause fermentation which will break down phytic acid. However, when adding an acid like lemon juice or ACV, you must add a phytase rich grain like buckwheat to break down phytic acid effectively. Is this because the bacteria present in cultured mediums will break down the phytic acid in the oats regardless of phytase availability from the oats themselves? That is, if fermentation is happening, phytase does not need to be present to break down phytic acid because it is actually the bacterial activity breaking down the phytic acid?

    1. Hi Luke,

      The lactobacilli, or bacteria in the fermenting liquid, can acutally produce phytase. Without the bacteria, as in the case of a lemon juice soak, most people would benefit from adding a phytase rich grain to the soaking liquid. But the soaking process alone does stimulate phytase and reduce phytic acid. I hope this helps! I may sound like a pro, but all this science-y stuff is new for me too! That’s about as far as I can explain it.

    1. Hi Keith,

      Cooking does not destroy the vitamins and minerals that we hope to gain from consuming oats. You can think of oats like grains or rice or even conventional flour. We wouldn’t benefit from eating those raw, would we? The grains (or seeds of grasses) need to be cooked in order to assist in the digestive process and eliminate toxins.

      It’s easy to confuse the benefits of eating raw vegetables (to preserve the enzymes, phytonutrients, and antioxidants) with the benefits of cooking other foods. If we focus on what we wish to obtain from the certain food (i.e. vitamins, macronutrients, minerals, antioxidants, or phytonutrients) it can help us determine whether it is better to eat cooked or raw. In this case, regarding grains, we are interested in the vitamins, minerals, and possibly proteins, and fats. All of which are preserved and more accessible when we cook them.

      Hope this helps!


  10. I finally found an article that explains what I’ve been seriously wondering!! I knew the science behind it all but seeing ALLLLLLLLLLL the posts on pinterest about “overnight oats” in the fridge had me wondering if I was MISSING SOMETHING??? Uh, nope! lol… so thank you for the confirmations. ALSO I’m commenting to commend you on your amazing and refreshing positive responses to everyone who has left comments and questions, many of which are nearly exactly the same. In a world of impatience, this was so nice to witness. 🙂

    1. Sounds like you’re ahead of the game Madelyn! Your instincts are working in your favor. Thank you so much for your comment. I think I have patience here for several reasons; mainly because I’m happy to see readers are interested in my post, and because I know EXACTLY how they feel to be so confused. For some reason, this stuff is so confusing to must of us who were born after 1950.

  11. Can you please explain the reason for cooking the soaked oatmeal in whey to get the good bacteria’s fermenting only to ruin them in cooking them? I don’t understand what’s wrong with eating them uncooked if they have soaked for 24 hours. I’d love to know more if you can explain! Thanks:)

    1. Hi Tina, I know this can be so confusing! Really what we want the good bacteria for (in the soaking stage) is to start “digesting” the grain for us. We’re also stimulating Phytase, an enzyme needed to break down the phytic acid. After that, we don’t really need the bacteria anymore. They’ve done their job! We want to cook the oats afterwards because there’s still more work to do. It’s a combination of soaking/fermenting AND cooking that will eliminate most of the phytic acid and troublesome lectins in grains (also known as seeds of grasses). This is a traditional method of food preparation for a reason; our ancestors learned that this was the ideal way to consume nuts and seeds in order to make them healthful. Groups who did this would thrive, and those who didn’t would become sick over time. I hope you find this information useful!


  12. Hello,
    I’m going on vacation next week and I am thinking about eating overnight oats for breakfast after reading your article.
    But is it necessary to cook the oats that are soaked in warm water? Or is it still safe for me to eat them without cooking them afterwards?

    1. Hi Cindy,
      Cooking is a very important step in my opinion. Are you planning to eat this on vacation where you will be without a stove or microwave? If the answer is yes, then here’s my suggestion: Soak the oats in a glass bowl for 24 hours as instructed in the recipe. Then when you’re almost ready to eat, pour HOT water from the coffee machine over your oats and cover with a plate or something to keep the steam in for 10 minutes. If you have a microwave then you can just cook them in there (or boil the water in there). I wouldn’t skip the cooking step, especially if you plan to do this more than once a week (the effects it can have on you depends on your current state of health and digestive symptoms). I hope this helps! Thanks for reading Cindy!
      -Marisa Moon

    1. Hi Amanda,
      You’ll notice when you soak them, the liquid is compltely absorbed by the oats. Feel free to rinse if you wish, but there’s no need to (and possibly benefits when avoiding the rinse). Enjoy!

  13. Hey mind explaining why it shouldn’t be in the refrigerator? You kinda only explained what soaking in room temperature does :).
    Also, won’t milk go bad overnight in room temperature? I’m quite scared of getting food poisoning.
    I noticed as I soak my oats longer there seems to be a layer of sticky substance above the milk, do you know what that is too? thanks alot!

    1. Hi there Pamela, I had the same questions myself a while back before getting into fermented and cultured foods. Milk has to be refrigerated only so it doesn’t spoil, but when milk spoils it’s actually going “sour” like the expression implies. The bacteria in the milk starts to breakdown the lactose (sugars) and releases a byproduct called lactic acid. This is the good stuff! This process is old-school buttermilk…milk that’s gone sour or allowed to ferment. Either way, just to clarify, my recipe is calling for yogurt or the liquid from your yogurt (lactic acid whey), or acid like lemon juice/apple cider vinegar. By using these already cultured ingredients you are jump-starting the process of good bacteria. And yes, the result is sticky…even slimy and a film is formed on top. This is good! I hope this information helps you understand a little more about this old-fashioned, safe, and natural process. These are the type of bugs that have the ability to protect you from food poisoning or other bad bacteria. Enjoy!

  14. I’m just wondering since yogurt and milk have to be refrigerated, how do they not go bad overnight when left out for several hours?

    1. That’s a great question! The good bacteria in the yogurt are thriving when left out with “food” to eat like oatmeal. So in this case, instead of spoiling, they are fermenting; and the good bacteria are multiplying. Does that make sense?

  15. Well I have one more question to do with cooking oats. I like to meal prep (24hr in advanced) and I have just started cooking them in the microwave for 2 to 2:30min. Is this ok or should I cook it a bit longer in a pan.

    Sub question (needn’t be answered): Do I need to soak steel cut oats.

    1. I know it’s a tough adjustment to make, but I highly recommend heating the oats on the stovetop (or even in the oven around 200F if you don’t want to tend to it). The microwave destroys nutrients, so what’s the point of trying to make a nutritious meal if we damage it in the microwave?

      I don’t know enough about steel cut oats to be sure, but I do understand that they are not processed as much as rolled oats which means they will be harder to break down when soaking, cooking, and digesting. I recommend a 24 hour soak and cooking until very soft.

      1. Thanks for the reply. That’s a great idea about heating in the oven, I can put them in go for 20-30 min run then it should be good by the time I return — all good things take time.

    1. Hi Anton,

      Greek Yogurt is similar to regular yogurt, but it has even more of the “whey” removed…which is why it is thicker. The whey is really what does the magic here, but that doesn’t mean it won’t work; there’s still some whey left in that greek yogurt or it would be cheese! I think you should try it and see how you like it. Otherwise just use a little lemon juice or vinegar and you’re good to go.

      1. Thanks I will. I have been using cyder vinegar for a while and putting it in the fridge. I tried microwaving some for breakfast the other day a felt really good in comparison with eating it cold. Thanks for the info.

  16. Wow Marisa, thanks for the audio version!
    That is so awesome, what a time saver, and you are enjoyable to listen too.
    That is eye opening about soaking grains and acids. Your mission is admirable and inspiring as I look to improve my nutrition.

  17. Great post! I just started eating overnight oatmeal, and I’m going to have to start adding in some whey or yogurt! I also soak rolled oats overnight in some almond milk, and I eat it cold like muesli. I don’t cook it in the morning. Should I?

    1. Hi Jim, Thank you! That muesli style oatmeal sounds great. I would suggest you add 2 Tablespoons of a plain almond milk yogurt (I buy a brand called Kite Hill) to your soaking liquid; check to be sure the one you buy has live cultures on the ingredient list. Then, if you don’t cook it there will still be less phytic acid and more breakdown of the outer bran. If you eat it regularly, like more than twice a week, or eat grains and legumes daily, then I suggest you cook it in the morning too. Just cook it all at once and save the leftovers for the cold version. I hope this helps!

      1. Thanks Marisa. I’m off to Whole Foods so I’ll look for that yogurt. I’ve been eating that muesli or overnight oatmeal for breakfast for a couple of weeks now to see how it makes me feel. So far so good! I could totally cook it too. I cook the oatmeal in the morning, and I use steel cut oats. For some reason, I don’t cook the rolled oats I use for muesli. Go figure. Should probably just cook both 🙂

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