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Soy Products – Low FODMAP or Not?

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Can I eat soy on the low FODMAP diet? This is a great question and one we hear all the time. And the answer is, yes, no and depends. What we can say definitively is that the low FODMAP diet is not soy-free.

Types of Soy Products that are okay to eat on the Low FODMAP diet

As with many attributes of the low FODMAP diet we have to pay attention to detail.

We are going to break it down for you, step-by-step, so that you will be well equipped with the info you need to seek out which soy products are low FODMAP, and appropriate during the Elimination Phase, and which to avoid.

Maturity of Soybeans & Processing Counts

A selection of soy based products

The reason why some are okay and some are not is because the maturity of the beans and/or the manufacturing process reduces the FODMAPs in soybeans and some soy products.

Related Articles: Soy and The Low FODMAP Diet and Are Soy Sauce and Tamari Low FODMAP?

By the way, soy is sometimes listed as “soya” on labels. Same thing with same FODMAP implications.

Low FODMAP Soy Products

This section shows you the many soy products that you can enjoy, even during the Elimination Phase.

Firm and Extra Firm Tofu

Firm and extra firm are low FODMAP as enough of the whey is drained away as the curds are pressed into the firm cakes; it is the liquid whey where most of the FODMAPs reside. Silken tofu has a very small low FODMAP serving size, as less whey is removed.

  • Monash University lab testing suggests a 170 g serving of firm tofu is low FODMAP, becoming Moderate for FODMAPs at 175 g.
  • FODMAP Friendly lab testing suggests a 100 g serving of firm tofu is low FODMAP.

Monash University calls these “plain” and “firm” tofu, so be aware of terminology going from their Australian perspective to U.S. labeling. FODMAP Friendly uses the “firm” tofu designation, as well.

Silken Tofu

While firm and extra firm tofu are pressed firmly and therefore the FODMAP filled whey is drained away, silken tofu (also called soft tofu) is not pressed and is, therefore, richer in FODMAPs. However, we include it in this section because it does have a low FODMAP serving, and the amount is enough to make a silky salad dressing, or to add to a smoothie.

  • Monash University lab testing suggests a 39 g serving (approx. 2 Australian tablespoons) of silken tofu is low FODMAP, becoming Moderate for FODMAPs at 46 g.
  • FODMAP Friendly lab testing suggests a 36 g serving of silken tofu is low FODMAP.

Fresh or Frozen Edamame in the Pod

fresh edamame.
Image by Dédé Wilson for FODMAP Everyday.

Edamame are young soybeans in the pod. Their immature state yields a different FODMAP profile than the mature beans that are used to make soy flour, for instance.

If you are lucky enough to have access to fresh, by all means, check them out. I found the ones in the image above at our local farers market in New England. Otherwise, it is fairly easy to find frozen in natural food stores. Simply steam the pods and serve warm or room temperature sprinkled with coarse salt.

Monash has tested edamame and a low FODMAP serving of shelled pods – you are just eating the beans themselves – is ½ cup (75 g) of the beans. They become Moderate for FODMAPs (fructans) at 195 g, so there is a lot of wiggle room.

When we shelled them from fresh, ¼ cup of the actual soybeans came from 30 pods! They typically have 2 to 3 beans per pod so you can eat a lot! Relax and have a little snack.

Frozen Shelled Edamame

All the same info for this stands as in the above bullet point, however, since these come already shelled it is much easier to overdo and eat too many.

They are great tossed into soups or stir-fry dishes; just pay attention to serving size.

Soy Sauce

Soy sauce comparisons.

Thankfully soy sauce has been lab tested by both Monash University and FODMAP Friendly. Whatever you use, make sure it is naturally brewed for best taste.

  • Monash University lab testing suggests a 2 Australian tablespoon (42 g) serving of soy sauce is low FODMAP. There is no further information and it appears that the 2 tablespoon suggestion is per Australian healthy eating guidelines.
  • FODMAP Friendly lab testing shows no FODMAP content and the directions are, “Enjoy in unlimited amounts; Eat freely.”

Shoyu

Another term for soy sauce, which is made from a combination of soy and wheat. It is often thinner in texture.

Tamari

This is wheat free, often labeled as gluten-free and has a slightly thicker texture and bolder flavor. While neither shoyu nor tamari is directly addressed by Monash we suggest you could try them and see how you do.

Sweet Soy Sauce/Ketjap/Kecap Manis

This is a thick, sweet liquid soy condiment. Monash University has lab tested it and a low FODMAP serving size is 1 Australian tablespoon (20 g), becoming Moderate for FODMAPs (fructans) at 50 g.

Soybean Oil

As with all oils, the carbohydrate and FODMAP content is zero. You can enjoy oil made from soybeans.

Soy Lecithin

You might notice this ingredient listed in packaged foods and on labels for many chocolate bars. Soy lecithin is a combination of an oil and fat and is therefore considered low FODMAP even though it hasn’t been formally tested.

As far as your chocolate bars go, it is used as an emulsifier and it is used in very small qualities.

Soy Protein Isolate

protein powder being scooped out of jar.
 Photo credit: ภาพของ Chakrapong Worathat via Canva.

FODMAP Friendly has lab tested this powdered product, which you might find as a standalone ingredient, or in protein powder products. A low FODMAP serving size is 30 g, with a max low FODMAP serve of 68.40 g.

Soy Milk Made from Soy Protein or Soy Protein Isolate

Soymilk made from soy protein, not whole soybeans, has generous low FODMAP servings of 1 cup (250 ml) per Monash and FODMAP Friendly lab testing; FODMAP Friendly shows a max serve of 3 cups (750 ml).

A U.S. based brand – 8th Continent – made with soy protein is available in some areas with limited availability and would be worth seeking out. (As of Q3 2024 we cannot source it anymore).

Soy Milk Made from Soybeans, Hulled and Unhulled

Drinking milk.
Image credit Goksi via Shutterstock.

Both Monash University and FODMAP Friendly have lab tested soy milk made from soy beans. (Please note that Monash uses both grams and milliliters somewhat arbitrarily).

  • Monash University has lab tested 2 different soy milks made from whole soybeans and a low FODMAP serving ranges from 30 ml (about 2 tablespoons) to 45 ml, but it does not become Moderate for GOS and fructans until about 120 ml.
  • Monash University has lab tested soy milk made from hulled whole soybeans and a low FODMAP serving is 60 ml (about ¼ cup), but it does not become Moderate for GOS and fructans until ½ cup (120 g).
  • FODMAP Friendly has lab tested soy milk made from whole soybeans and they state no low FODMAP serving.

Soy Yogurt Made from Soy Protein or Soy Protein Isolate

If you can find soy milk yogurt made from soy protein or soy protein isolate and NOT whole soybeans, it might be worth giving a try. Use the soy milk made with soy protein amounts as guides. Read the label for other FODMAPs.

Monash has an app entry for soy yogurt and shows a 2 tablespoon (38 g) low FODMAP serving; we assume this is made from whole soybeans.

Miso 

This fermented soybean product is a classic Japanese condiment and can be used in sauces and soup.

  • Monash University lab testing states miso is low FODMAP up to 12 g, but does not become Moderate for fructans until 75 g.

We measured it out for you! 12 g equals about 2 American teaspoons. Monash states it is 1 Australian tablespoon (these numbers do not match). If you are new to Miso, we highly recommend South River brand.

  • FODMAP Friendly has lab tested miso as well and states a low FODMAP serving is 15g, with a max low FODMAP serve of 45 g.

Tempeh

tempeh cut into fingers

This is made from lightly fermented soybeans that have been pressed into a cake. Make sure you read labels and look for plain tempeh; many are packaged already flavored and high FODMAP ingredients might be used.

Both Monash and FODMAP Friendly have lab tested tempeh.

  • Monash University lab testing states plain tempeh is low FODMAP up to 100 g. Initial lab testing showed servings higher than 220 g contain high amounts of fructans and GOS. Current lab tests show no further information beyond the 100g, which we believe is an Australian healthy eating guideline.
  • FODMAP Friendly has lab tested plain, cooked tempeh and they found no FODMAPs. “Enjoy in unlimited amounts; eat freely.”

PS: 100 g of plain tempeh is a piece that is 4.5-inches by 1.5-inches by 1-inch thick (11 cm by 4 cm by 2.5cm thick).

Douchi (Fermented Black Soybean)

Monash has lab tested douchi and it is low FODMAP in 1 Australian tablespoon (15 g) portions.

High FODMAP Soy Ingredients

The following soy ingredients are generally cosidered to be high FODMAP.

Soy Yogurt Made With Whole Soybeans

Popular brands, such as Silk, are made from soymilk made from whole soybeans (label lists “Filtered Water, Soybeans”), so it is not recommended during the Elimination Phase.

Soy Flour

This is made from grinding mature dried soybeans and is, therefore, a product that is concentrated with FODMAPs. Please note that soy flour is considered high FODMAP, and yet it is within certain products that have been lab tested and certified as low FODMAP. We do not know what an exact low FODMAP serving size is. In general, consider it high FODMAP.

Kinako, which is roasted soybean flour, would likely be the same as raw soy flour, in terms of FODMAP content.

Mature Soy Beans

Mature soybeans, either dry or fresh, are high in FODMAPs. In the Monash app there is an entry for “dried, boiled, drained soya beans”, for which there is no known low FODMAP serving, and they tested down to 43 g.

Soy Nuts

This is an educated assumption on our part but soy nuts are made from mature soybeans, so we bet, once they are tested, that they will be high in FODMAPs. Best to avoid for now.

Textured Soy Protein (TVP)

Monash has lab tested TVP and there is no known low FODMAP serving size – and they have tested down to 15 g.

Untested Soy Products

These are soy ingredients that have not been lab tested and should be treated as having unknown FODMAP content. Please see our article, What If A Food Hasn’t Been Lab Tested For FODMAPs?

  • Soybean sprouts
  • Dark soy sauce: From the bottom of the fermentation bottle; almost as thick as molasses
  • Light soy sauce: Much thinner in viscosity, and paler on color
  • Mamenori (soybean paper)
  • Okara: Byproduct of tofu production
  • Soy cheeses and non-dairy products

Soy Product To Try

Natto is fermented soybeans and might be worth a try. The fermentation would reduce the FODMAPs; we just do not know by how much.

Low FODMAP Recipes To Enjoy Featuring Soy

Banh mi tofu brown rice bowl in dark wooden bowl_
Monash University Certified Low FODMAP Tofu with Baby Bok Choy and Oyster Sauce
Asian-Tofu-Noodle-Papaya-Salad-on-a-gray-plate.
Photo credit Dédé Wilson.
Overhead image of Low FODMAP Vegetarian Hot and Sour Soup in white bowl with scallions
Image credit: Dédé Wilson from FODMAP Everyday®.
low FODMAP Pork Dumplings on brown plate with dipping sauce in white bowl 1
overhead image pad see ew in white bowl
closeup of low FODMAP tuna poke in brown bowl with chopsticks
Char Siu on white plate.
Image credit: Dédé Wilson from FODMAP Everyday®.

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