Tofu is a bit of a mystery for some people. If you’ve never tried it before, tofu can seem intimidating or a bit foreign, especially if you’ve had a traditional Westernized upbringing.
But if you’ve had tofu before, then you know how tasty it can be no matter how you prepare it.
Tofu is made from soy, which is controversial on the keto diet. This is because soy falls into the legume and bean categories and these are not allowed on the keto diet.
But many soy products are surprisingly low in carbs and fit well in the keto diet if you use them in moderation. They are also ideal for those who follow a vegan or vegetarian keto diet.
Here is everything you need to know about tofu and whether or not you can consume it on a keto or low-carb diet.
What is Tofu?
Tofu is soybean curd that looks like soft, white cheese. By definition, it’s a salt and water extracted coagulated gel made of soy protein, soy lipids, and other compounds.
Tofu originated in China and can be found in many East Asian dishes. It has been used in Japan for over 2000 years, but the Westernized world was only first exposed to tofu approximately 100 years ago (1).
One of the best things about tofu is that it is a very versatile food. It often takes the flavor and texture of your cooking method. It can be used in vegetable and meat-based dishes alike or processed into tofu products, such as savory tofu, deep-fried tofu, or secondary tofu products.
You can also freeze, ferment, fry, saute or grill it. There is no limit to how you can prepare tofu!
The shelf-life of tofu can vary from one to five days for fresh tofu to one month for the pasteurized kind and up to two years for extremely processed tofu.
You can make different types of tofu by altering some of the materials needed to make it, such as soymilk, beans, and full flakes.
Firm tofu is known as “momen” in Japan and has more of a cheese-like texture. Silk tofu is known as “Kinugoshi” and has a delicate texture.
Here are some interesting facts about soy and tofu (2):
- Some factories in Japan eat two to three tons of soybeans each day
- Soy is a complete source of protein, which means that it contains all the essential amino acids (not many plant-based sources of food can claim this!)
- In 2014, approximately 85.5 million metric tons of soybeans were harvested in the United States alone
- Only 2% of soy production is used for human consumption and the rest is intended for animal feed
- Approximately 25% of people in the United States eat soy foods at least once a week
- People in Japan eat an average of 8.7 grams of soy each day
- Koreans eat 6.2–9.6 grams of soy per day
- Indonesians eat 7.4 grams of soy per day
- People in China eat 3.4 grams of soy each day
How Is Tofu Made?
Tofu is made by puréeing cooked soybeans and turning the curds into solid form.
First, the soybeans are ground in water, heated, and then mixed with minerals such as calcium sulfate, magnesium chloride, and glucono-delta-lactone.
This turns the soy into a solid, block form known as tofu. Curds can be pressed into different textures to form soft, firm and extra-firm textures.
The firmness of the tofu you buy should compliment your cooking style. For example, you can buy firm tofu if you plan on grilling it or frying it in place of meat. Soft tofu can be used in soups or other delicate dishes. You can also use tofu to form meatless patties.
Nutrition and Net Carbs in Tofu
Tofu isn’t as high in net carbs as other forms of legumes and beans, such as peanuts, black beans or peas. Because of this, it puts tofu in somewhat of a gray area when it comes to eating it on a low-carb diet.
Here is the nutritional breakdown of a 100-gram serving of firm tofu (3):
- 76 calories
- 4.8 grams of fat
- 1.9 grams of carbs
- 0.3 grams of fiber
- 1.6 grams of net carbs
- 8.1 grams of protein
As you can see, tofu is relatively low in carbs and contains a good source of protein. It’s one of the few plant-based foods that contains a complete protein or one that has all of the essential amino acids. This is a trait normally found in meat and animal products.
Health Benefits of Tofu
Soy is one of those foods that is debated among health experts. Many will tell you not to eat it because it has estrogen-like effects on the body and may contribute to hormone problems. This may increase the risk of cancer and other serious ailments.
On the other hand, some studies suggest that soy helps reduce the risk of cancer, especially breast cancer. It’s also a complete protein, which makes it an ideal source of protein for vegan dieters.
Basically, soy is a very controversial food. Let’s go over the pros and cons of soy.
Here are some health benefits of soy:
#1. It may lower blood pressure
Eating higher protein foods has a positive effect on blood pressure. Two studies found that there were notable reductions in blood pressure among people who ate soy.
One found that eating 25 grams of soy per day helped postmenopausal women lower their blood pressure. The other found that drinking soy milk helped men reduce their blood pressure (4, 5).
Meta-analyses show that the reduction in blood pressure among soy-consuming groups was a modest 2.5 and 1.5 mmHG, respectively.
However, if the idea behind these studies is that protein is responsible for lowering blood pressure, then you can get it elsewhere without having to rely on soy.
#2. It may improve skin conditions
Because of its ability to bind to estrogen receptors, isoflavones in soy have been linked to improved skin conditions.
This includes improvements in skin’s elasticity, pigmentation, vascularity, and water-holding capacity to keep it hydrated. Estrogen receptors may also positively affect hair follicles and skin appendages (6).
#3. It reduces hot flashes
One of the reasons why women of menopausal age eat soy is because of its ability to reduce hot flashes. One study found that soy reduces hot flashes by up to 26.2% (7).
#4. It’s a complete protein
Many people think that vegan and vegetarian dieters lack protein. However, there are some plant-based foods that are high in protein, such as quinoa and soy.
Research shows that soy is a complete protein, which means that it contains all essential amino acids. Amino acids are important because they are needed to help build protein (8).
Not many plant-based foods are considered complete proteins. Amino acids are primarily found in animal products, which makes soy an exceptional plant-based complete source of protein.
Protein has been shown to reduce the risk of chronic diseases, especially heart disease and diabetes, and help prevent obesity. It is also needed to help you build lean muscle.
#5. It may help bone health
Research shows that estrogen therapy reduces postmenopausal bone loss and the risk of hip fractures by approximately one-third (9).
Because of its estrogen-like effect on the body, there is some evidence to show that soy foods can help promote bone health and bone strength in women (10).
This is especially important in postmenopausal women who tend to have higher rates of low bone density and increased risk of fractures.
#6. It may improve kidney function
Some Research indicates that the type of protein found in soy places less stress on the kidneys than other high-quality proteins. This means that it could reduce the risk of developing renal disease over time in people with diabetes (11).
#7. It reduces cholesterol
According to one study, soy protein has a modestly hypocholesterolemic effect on the body. There is also evidence to suggest that soy lowers the risk of coronary heart disease (12).
Possible Side Effects of Tofu and Soy Products
Depending on your source of information, tofu may have a longer list of cons than it does pros.
There is conflicting information when it comes to its effect on cancer. Other research shows that the isoflavones in soy contribute to hormone problems.
Here is a list of possible side effects of tofu:
#1. It may cause cognitive impairment
According to one study, higher intakes of tofu were associated with cognitive impairment and brain atrophy later in life.
The researchers took surviving patients of a study established in 1965 for research on stroke, cancer, and heart disease. Information from this study was available from interviews that were conducted from 1965 to 1967 and 1971 to 1974 (13).
Researchers separated participants into a low consumption of tofu and a high consumption of tofu category. They labeled men who had two or more servings of tofu per week as high tofu consumers. Cognitive functioning was tested when the participants were 71 to 93 years old.
Neuroimage and autopsy were used to determine brain atrophy. Then, cognitive function was analyzed on the wives of the participants because they had been living with the subjects during the time of the study.
Results concluded that enlargement of ventricles, low brain weight, and poor cognitive test performances were linked to a high intake of midlife tofu consumption. Similar results were associated with the wives of the test subjects.
#2. It may cause hormonal imbalance
Isoflavones are a bioactive compound found in soy. Research shows that isoflavones have a similar chemical structure to the hormone estrogen. This allows it to bind to estrogen receptors in the body and mimic the hormone, causing hormonal imbalances (14, 15).
Isoflavones may contribute to hormone disruptions due to heightened estrogen in the body. Estrogen dominance has been associated with symptoms that include weight gain, mood fluctuations, and menstrual problems in women.
Research shows that women who eat soy increase the length of their menstrual period and delay their ovulation by one day (16).
Here comes the confusing part. Several studies have identified that isoflavones have both tumor-promoting and anti-cancer properties. This means that there is data to suggest that soy isoflavones may both prevent cancer and promote it (17, 18, 19, 20).
This is one of the many reasons why there is so much controversy circling soy in the healthcare community.
#3. It may interfere with thyroid medication
Research shows that foods made with soy increase the amount of medication needed by patients who have hypothyroidism.
This is not due to the effect that soy has on the thyroid, but it’s because soy interferes with the absorption of some of these medications, especially levothyroxine (21, 22, 23).
If you have hypothyroidism and take medication to help control this disease, then you may want to stay away from soy.
#4. It may cause inflammation
Another area that is confusing when it comes to soy is its effect on inflammation. Previous studies have shown that inflammation has a detrimental effect on the body. It has been linked to many chronic diseases, such as cancer, obesity, and type 2 diabetes.
Some research indicates that the isoflavones in soy have an anti-inflammatory effect on C-reactive proteins in the body to reduce total inflammatory markers (24).
Other research shows that soy products may contribute to inflammation. For example, soybean oil has a high amount of omega-6 fatty acids which cause inflammation (25, 26).
#5. Isoflavones may increase the risk of cancer when taken in supplement form
Some research shows that the long term use of soy isoflavones supplements may increase the risk of a process that thickens the lining of the uterus known as endometrial hyperplasia. This increases the risk of cancer (27).
However, it should be noted that eating soy foods does not appear to increase this risk. For this reason, it’s not a good idea to supplement with isoflavones and only get them from eating moderate amounts of soy food.
Is Tofu Keto-Friendly?
As you can see, the information surrounding soy is confusing. Should you eat tofu or not? The answer may depend on your personal preference. It may also depend on your carb allowance and tolerance for soy.
Soy is generally not recommended on a strict ketogenic diet because it falls into the category of legume and legumes might cause inflammation in some people. Typically, legumes contain too many carbohydrates to be eaten on a strict ketogenic diet. Furthermore, up to 94% of soybean crops are genetically modified, which is very controversial as well (28).
For a list of foods to eat on keto, read this guide!
However, as you can see from the nutritional information above, a 100-gram serving of tofu contains just 1.6 gram of net carbs per serving. This means that you could add tofu to your low-carb diet if you eat it in moderation only.
Some people find soy hard to digest, especially those with digestive disorders or symptoms. For this reason, many people on low-carb diets avoid soy altogether because it’s too taxing on their digestive system.
If you are not allergic to soy and want to try a vegan or vegetarian ketogenic diet, then you may wish to add tofu and soy to your diet plan. In the end, the decision to add soy to your low-carb diet is a personal choice and tolerance.
Conclusion
Tofu is made from soy, which is a controversial subject among the healthcare community. Many health experts recommend staying away from soy because of its estrogen-like abilities in the body. This may increase the risk of cancer and hormonal imbalances that contribute to weight gain, mood disorders, and menstrual problems in women.
On the other hand, tofu is a surprising source of low carb protein. A 100-gram serving of tofu contains only 1.6 gram of net carbs. It also has numerous health benefits, such as improving skin health and providing a complete source of protein.
The question as to whether or not you should add soy to your low carb diet is a personal choice. We do not recommend soy on a strict ketogenic diet because it falls into the category of a legume. Legumes tend to be hard to digest for many people, which is why they turn to a low-carb diet in the first place.
If you wish to try soy on your diet, then we recommend sticking to small servings to start with. You can experiment with different textures of tofu that range from soft to firm depending on your style of cooking.
Finally, if you are looking for a soy sauce substitute, you can try coconut aminos. It has more health benefits and is much more keto-friendly.
Up Next: Can You Eat Edamame On Keto Diet?
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