Is soy low FODMAP? Yes and no. Soybeans are not low FODMAP but some soy products are low FODMAP. The answer to “Is soy low FODMAP” is not so straight forward. Soy FODMAP depends on a number of things, serving size, processing method, and bean maturity being a few of them.
So, that’s what we’ll talk about today. Here’s a run down of everything we’ll be covering in this post:
- Is Soy Low FODMAP?
- Types of Low FODMAP Soy Products
- Avoid These Soy Products
- Untested Soy Products
Let’s kick this off with the most important question and the reason you’re here: is soy low FODMAP?
Is Soy Low FODMAP?
The FODMAP level depends on the serving size, processing method, and bean maturity, among other things. A low FODMAP diet doesn’t mean a soy-free diet. Soybeans, soy milk (made from soybeans), and silken tofu contain high FODMAPs. But soy products like miso, firm tofu and soy sauce can be okay.
Soybeans contain galactans and fructans which are FODMAPs. Just because soybeans are high FODMAP, doesn’t mean soy products need to be removed from your diet. If the ingredient is processed and the FODMAPs are changed, there’s a good chance you can have it.
Soy is a great example of that. Silken tofu contains high levels of FODMAPs but firm tofu is low FODMAP at 170g . Both tofus come from soybeans but the end product is different. The difference is the water content. Silken tofu has more liquid and that liquid contains water-soluble FODMAPs, particularly GOS (galacto-oligosaccharides) and fructans.
Not all soy products are low FODMAP but some of them have been. The next thing we’re going to look at is s complete FODMAP list of which soy products are okay for a low FODMAP diet.
Types of Low FODMAP Soy Products
Quick disclaimer: Monash university (the creators of the low FODMAP diet) tested these products. But no two people are the same. These are the suggested serving sizes according to Monash’s research but please listen to your body and figure out what you can or can’t tolerate.
Also be sure to read the back of the ingredient label. Low FODMAP products can contain other ingredients that may be high FODMAP. With that out of the way, let’s talk about soy and IBS. Below is a list of soy products that Monash has tested and are FODMAP-certified .
Mature soybeans are a no go but immature soybeans are okay for IBS. Edamame beans are young soybeans that are low FODMAP at 90 grams. They’re no longer low FODMAP at 210 grams and contain high FODMAPs.
Another way to sneak in soybeans into your diet is with tempeh. Tempeh is low FODMAP at 100 grams or 3.5 ounces. This soy product is made from fermented soybeans that are pressed into a large block.
Think of it as chunky and dry tofu. Tempeh is a great source of protein and is absolutely delicious.
Miso paste is made from fermented soybeans and is used a lot in Japanese cooking. The recommended serving size is 12 grams or 2 tablespoons. Buy miso that’s been fermented the traditional way without any additives.
More about miso and FODMAPs here.
The next soy product is soy sauce.
Light Soy Sauce
Soy sauce needs no introduction and is low FODMAP at 42 grams or 2 tablespoons. Check the label to make sure it’s been naturally brewed. Soy sauce is fermented with wheat so, although it’s low FODMAP, it is not gluten-free and should be avoided by people with celiac disease or wheat intolerance.
Some soy sauces have chemicals added to them to give them flavor that mimics the fermented process. The fermentation process soy sauce goes through is very important and changes the FODMAP levels.
Our next product is a type of Japanese soy sauce that is gluten-free.
Tamari (Or Shoyu)
Tamari is a type of Japanese soy sauce that is a byproduct from making miso. So it’s an ideal soy sauce for IBS and gluten-free diet. It has not officially been tested but there is speculation that tamari is low FODMAP because it goes through the same fermentation process as soy sauce.
The recommended serving size for Tamari or shoyu is the same as light soy sauce, 42 grams or 2 tablespoons. The next item on our list is a type of soy sauce known as dark soy or sweet soy.
Sweet Soy (Ketjap Manis)
Sweet soy, ketjap manis, or dark soy has a recommended serving size of 20 grams or 1 tablespoon. It’s a type of soy sauce that’s used in cooking. It’s thicker and sweeter than regular soy. Curious about soy sauce & FODMAPs? Click here to read more about it!
Another product that often gets a bad rap for IBS is tofu but you can definitely have tofu on an IBS diet if you get the right kind.
Tofu can be categorized into 5 types: silken, regular, firm, extra-firm, and super firm. Only firm tofu is low FODMAP at 170 grams or 6 ounces. Soft or silken tofu contains more water-soluble GOS -a type of FODMAP.
Tofu is made from curdling soy milk and pressing those curds into a block. The more liquid present in the tofu, the softer it is. Which means the more GOS and the higher the FODMAP level. Firm tofu is pressed to get rid of that liquid and makes for a denser texture. The less water tofu contains, the lower the FODMAP content.
Wanna learn about tofu and FODMAPs? Click here to read about the different kinds of tofu.
Soy milk made from soybeans is high FODMAP but did you know there’s low FODMAP soy milk?
Soy Milk & Yogurt (Made From Soy Protein)
Having IBS and soy milk don’t mix, right? Wrong! Soy milk is usually made with the whole soybean and that’s high FODMAP but soy milk made from soy protein is FODMAP friendly. Soy protein soy milk IBS-friendly at 250ml or 1 cup.
Monash stated that soy milk is low FODMAP at 60ml or 1/4 cup and soy milk made from whole soybeans is low FODMAP at 30ml or 2 tablespoons.
The same rule applies for soy yogurt. If the yogurt is made from soy protein soy milk then the soy yogurt is low FODMAP but it may be high FODMAP if it’s made with regular soy milk. Soy milk is an ingredient in another popular soy product: soy cheese.
Vegan cheeses made from soy are common and although soy cheese is low FODMAP at 40 grams, make sure to read the back of the ingredient label. There are plenty of vegan soy cheeses that have high FODMAP ingredients like garlic powder or inulin (chicory root) and it’s always best to avoid them.
Here’s an example: This vegan cheddar from Follow Your Heart is dairy free and made with soy powder and soy protein but it also lists inulin as one of the first few ingredients. Ingredients are listed from highest content to lowest in the product.
Soybean oil is low FODMAP because fats are FODMAP-free. Remember that FODMAPs are short chain carbohydrates and there’s zero of that in oils or fats. Another soy product derived from oil is soy lecithin.
Soy lecithin is an additive that’s added to processed food. It’s a mix of fat and oil which makes it low FODMAP. You can find it in your chocolate bars or used in products as an emulsifier, preservative or lubricant.
Now that you know which soy products are OK for IBS, let’s talk about the ones that are high FODMAP.
Avoid These Soy Products
These products have been tested by Monash university to contain high levels of FODMAP and should be avoided because they can trigger IBS symptoms. Ideally, you want to avoid these foods at all costs but everyone is different. I can eat a whole block of silken tofu and have no problems.
No two people have the same reaction to these foods and I recommend testing it for yourself (with caution and gradually).
You can eat young immature unripened soybeans known as edamame but soybeans in their mature form, dried or canned contain high amounts of galactans and fructans. To be fair mature soybeans can’t be eaten raw and need to be soaked, processed into flour, or fermented to be eaten.
Sometimes you can get roasted soy nuts as a snack but they are not low FODMAP.
Roasted Soy Nuts
Made from roasting whole mature soybeans, it’s no surprise that soy nuts are high FODMAP. Next, is soy milk low FODMAP?
Soy Milk & Yogurt (Made From Soybeans)
Soy milk is only low FODMAP when made from soy protein. If soy milk is made from hulled soybeans it’s low FODMAP at 60ml or 1/4 cup and soy milk made from whole soybeans low FODMAP at 30ml or 2 tablespoons.
Other alternatives for plant based milk with larger serving sizes are almond milk (serving size 250ml or 1 cup) or rice milk (serving size 250ml or 1 cup).
Monash hasn’t tested soy yogurt. The FODMAP content can differ depending on the additional ingredients. As a general rule, avoid products like this or try to reintroduce them later on to see how your body reacts to it.
If you don’t want to risk it, then forget about soy yogurt and opt for lactose free yogurt or other low FODMAP ingredient based yogurt like coconut (recommended serving size 122.5 grams or 1/2 cup).
Finally, the last item on our list: silken tofu.
Earlier we covered why firm tofu is low FODMAP but silken tofu is high FODMAP because it has more water. That water is filled with GOS and should be avoided.
Now that we know which products should be eaten in moderation and which to avoid, let’s dabble in the gray area. Untested soy products, safe or not?
Untested Soy Products
The low FODMAP diet and lifestyle is relatively new, which means there are plenty of untested products. Here are a few untested soy products and speculation of their FODMAP levels by the fody’s out there.
Soy Ice Cream
First up on our list is soy ice cream. This hasn’t been tested but we know regular soy milk is low FODMAP in small quantities. So it’s easy to assume that soy ice cream is not okay.
Let’s also remember that ice cream has a lot of stuff in it. Some of those ingredients may have high levels of FODMAPs like inulin or chicory root. The next soy product on our list is soy protein powder.
Soy Protein Powder
Soy protein powder should be low FODMAP since soy milk made from soy protein is okay at 250ml or 1 cup. Again, Monash and FODMAP Friendly haven’t tested this. Er on the side of caution and make sure to check the ingredient list for additions like fructose that would affect the FODMAP levels.
The final ingredient on our list is a bit of a debate, let’s talk about soy flour.
Soy flour is in a lot of gluten-free products but Monash hasn’t tested it yet. To make soy flour, mature soybeans are ground finely. We know that soybeans contain high levels of galactans and fructans.
FODMAP Friendly tested 50 grams of soy flour and reports it’s not FODMAP Friendly . But Schär’s FODMAP certified digestive cookies have soy flour listed as one of their ingredients.
The verdict is that if soy flour is not the main ingredient in a gluten-free product and doesn’t contain other high FODMAP ingredients, it should be okay. But again, every person is different.
There you have it, is soy low FODMAP? What do you think? If you take anything away from this post, remember that serving size is key, knowing which products are FODMAP-friendly and most importantly know your tolerances.
Try making these low FODMAP Asian recipes if you want to add soy products into your diet: