What is tofu made out of? In the Chinese language the word literally means "bean curd" and that's exactly what it is. Similar to what happens in dairy milk production, when soy milk is made there are curds created. This fermented bean curd is then strained from the liquid and pressed together to create blocks of tofu. The remaining liquid is the soymilk.
Which diets does it work for?
Is tofu considered a raw food? No. The typical method involves soaking, mashing, and boiling the beans with water. The coagulation (the process of creating curd clumps) happens using an added ingredient. The most common is a salt coagulant; calcium sulfate. The acid coagulant, Glucono delta-lactone (GDL), is often used for silken and softer tofu. The least common are enzyme-based versions such as papain and proteases.
Since it does not need to be cooked first, many people on raw food diets are eating unheated/cold tofu and assuming it qualifies as raw, when it definitely does not. Recipes for real truly raw tofu are out there, but they're such a niche product they aren't commercially produced on a large scale. You can find them at some Whole Foods locations and other health food stores, but they're often expensive and go bad quickly. Limited dietary benefits compared to the high price you pay for it.
Is tofu vegan and gluten free? It's both! The most common types of tofu you will find at the grocery store will usually consist of just 3 ingredients; water, soybeans, calcium sulfate (or another non-gluten based coagulant).
When it comes to plain unflavored tofus - whether they're soft, firm, or extra-firm - we have never encountered one that contains wheat, barley, or other gluten ingredients. But if you're celiac or have gluten sensitivities, watch out for the processed soy meat replacements like cold cuts, vegan pepperoni, vegan hot dogs and soy sausage, etc. Most of those contain vital wheat gluten (and a lot of it) in addition to the tofu. Tofurky, Smart Deli, and Yves are usually all vegan products, but brands you will need to be careful of if you're gluten free (read the ingredients before buying).
Is tofu good for you?
This food has many nutritional health benefits, but also drawbacks. If you're dieting, is tofu good for weight loss? Very much so! It does not have carbs or more accurately, there's so little it's trivial. A quarter-block (around 4 ounces) only contains 2.2 grams. The USDA daily recommended intake of carbohydrates is 45 to 65% of your diet (with protein at 10 to 35% and fat at 20 to 35%). The exact amount of carbs that equals will vary based on whether you are a man or woman, young or old, active or not. Though it will be in the neighborhood of around 200 to 350 grams of carbs per day. That means a 1/4 block of tofu represents less than 1% of your daily carb allowance!
Not only does tofu have protein, it has a lot of it! This makes tofu great for you if you're vegan, vegetarian, or simply want a healthier low-fat source of protein in your diet. That 1/4 block yields 9 grams of beneficial protein. How much calories tofu has - only 88 calories for that serving size - means you can easily eat 2, 3, or even 4 servings at a meal and get the majority of your daily protein requirement for only around 300 calories.
3 reasons why it could be bad for your health
1. Fattening - Is tofu fattening? Answering this question isn't black and white. Roughly 50% of the calories come from fat; 44 from fat for an 88 calorie serving. Generally, anything that has more than 20% of its calories coming from fat is considered a fatty food. That being said, since tofu is such a low calorie food to begin with, it's far healthier for you than eating most types of meat which may have similar proportions of fat, but mostly in the saturated form and they're often loaded with cholesterol. Since soybeans are a plant, they have no cholesterol whatsoever. Zero.
2. Bad for men (in excess) - A couple of us at Superfoodly are vegan males (including one that's vegan + gluten free) and we try to limit tofu, tempeh, and similar soy-heavy foods to every other day. Why? Because soy has a heavy concentration of phytoestrogens. Those are not identical to the hormone estrogen, but they can mimic the same side effects within the biology of the human body.
Many people have the perception that estrogen is a female-only hormone but that's not true. Both men and women need estrogen. Women synthesize it from their ovaries while men make estrogen through an enzyme called aromatase, which converts testosterone into estradiol. So there are not just cons, but also pros for both males and females (1). However what is true is that the ratio of estrogen to testosterone in females is dramatically higher than what's natural for males (men need mostly testosterone). For that reason, men need to be careful with their total soy intake.
Is eating tofu everyday bad for men? Probably. Male soy consumption on a daily basis should be safe in small amounts, but eating big slabs of tofu for lunch and dinner daily is not a good idea if you're a man (in our opinion at least). It's not a myth that gynecomastia (male breast tissue growth) is a well known side effect that's possible with soy consumption (2). How much - or how little - it takes for that to happen will vary by individual. For some males it never happens, for others it does. Both regular and organic tofu have these phytoestrogen compounds in them. For these reasons, the vegan men here at Superfoodly try and limit things like Chipotle sofritos (fried tofu) bowls and Thai stir fry to no more than than 3x per week, if not less.
3. Incomplete nutritional value - Does it have nutrients? Absolutely! How much protein it has is quite impressive - its biggest benefit. But the value of vitamins, minerals, antioxidant activity is limited. Its ORAC value, which represents how much antioxidants in total it has, is extremely low. How bad? To put it in perspective, a Little Caesar's cheese pizza has twice the antioxidant content, if you're comparing on an equal weight basis. And obviously, pizza is a terrible source to begin with. Even iceberg lettuce has over 4x the amount as tofu.
Even with just a 1/4 block serving, tofu is a good source of iron (34% of daily value) and calcium (40% of daily value). It's a good source of the minerals manganese and selenium. Aside from those, it has lackluster levels of the other minerals and no vitamin C, A, D, E. It does contain K and B vitamins but only in small quantities. So there is nutritional value but eating it alone is not going to provide you everything you need.
Research Support, Non-U.S. Gov't: Carlsen MH, Halvorsen BL, Holte K, et al. Nutrition Journal NIH Jan 2010