Tofu is a very nutrient-dense, versatile food that can easily adopt the flavors of nearly any dish. For people with soy allergies -- one of the most common food allergies -- even a small amount of tofu poses a great health risk. If you do not suffer from a soy allergy, you can easily exceed your recommended daily intake for many nutrients by eating multiple servings of tofu per day. Because of the numerous potential risks of nutrient overconsumption, eating too much tofu is not healthy.
Protein and Amino Acids
Like other soy products, tofu is one of the only plant sources of all the essential amino acids. Unlike the non-essential amino acids, your diet is the only source of these building blocks of proteins. With nearly 20 grams of protein in a 1/2-cup serving, firm tofu is an excellent source of both total protein and essential amino acids. Even if you eat as much as 2 cups of firm tofu in a day, you will obtain only approximately 320 calories from protein. This is 16 percent of a 2,000-calorie-per-day intake, thus well within the recommendation in the 2010 "Dietary Guidelines for Americans" that 10 to 35 percent of your calories come from protein. However, as the Guidelines state that a healthy diet includes a variety of protein sources, you should not rely solely on tofu to meet your daily needs.
Fat and Calories
There are 183 calories in a 1/2-cup serving of firm tofu. As this is nearly 10 percent of a 2,000-calorie-per-day intake, eating too much tofu can quickly increase your caloric intake to unhealthy levels. This can result in unwanted weight gain and an increase in body fat. Another important consideration is that a 1/2-cup serving of firm tofu contains 11 grams of fat. In comparison with the 4 calories in 1 gram of protein, fat contains 9 calories per gram. With fat ideally accounting for 20 to 35 percent of your daily calories, you can easily exceed your daily intake by eating too much tofu. Although most of tofu's fat content comes from heart-healthy unsaturated fats, the 1.5 grams of saturated fats in a 1/2-cup serving can also become excessive if you eat multiple servings per day.
Tofu is an excellent source of many minerals, particularly iron and calcium. A 1/2-cup serving of firm tofu contains 18.6 percent of your iron and 86.1 percent of your calcium needs per day. Despite their importance for women's health, overconsumption of these nutrients can lead to digestive problems, kidney and liver damage, diabetes and an irregular heart rhythm. Eating as little as three servings of tofu per day can result in calcium toxicity. In addition, calcium interferes with iron absorption, thus reducing the potential benefits of tofu's iron content.
Oxalates and Phytates
Two other compounds that are present in potentially high concentrations in tofu are oxalate and phytate. Both of these compounds have important and contradictory effects on the formation of calcium kidney stones: oxalate contributes to their development while phytate helps to prevent them. Most tofu contains small amounts of oxalate and moderate amounts of phytate. This balance may be beneficial even at high tofu intakes if you suffer from kidney stones. However, as not all tofu contains the same oxalate-phytate ratio, you should avoid excessive tofu intake to reduce your risk of kidney health issues.
- Vegan Health: Protein
- U.S. Department of Agriculture National Nutrient Database for Standard Reference: Tofu, Raw, Firm, Prepared with Calcium Sulfate
- U.S. Department of Agriculture and U.S. Department of Health and Human Services; Dietary Guidelines for Americans, 2010
- University of Maryland Medical Center: Calcium
- University of Maryland Medical Center: Iron
- Journal of Agricultural and Food Chemistry; Oxalate and Phytate of Soy Foods
Matthew Lee has been writing professionally since 2007. Past and current research projects have explored the effect of a diagnosis of breast cancer on lifestyle and mental health and adherence to lifestyle-based (i.e. nutrition and exercise) and drug therapy treatment programs. He holds a Master of Arts in psychology from Carleton University and is working toward his doctorate in health psychology.