Soybeans: USDA Nutrition, Roasted Soybeans and What Research Says

Soybeans are the mature, dried seeds of the soy plant, the same plant that gives us edamame, tofu and soy milk. In USDA FoodData Central (SR Legacy), a cup of boiled mature soybeans lists about 296 calories, 31 grams of protein and 10 grams of fiber, which is roughly double the protein of most cooked beans. This guide covers soybean nutrition in USDA data, roasted soybeans, why dried soybeans are always cooked, soy allergy labeling, and what the research on soy isoflavones does and does not show.

Peptide Labs does not sell soybeans or soy foods. This article is general nutrition information, not medical advice, and it links no products: soy supplements are a different thing from the whole bean.

What are soybeans?

Soybeans (Glycine max) are legumes. The pods can be picked green, when the beans are sold as edamame, or left on the plant until the seeds dry and harden into the beige mature soybeans sold in bags. Most soy foods start from the mature bean: soaking and grinding gives soy milk, curdling soy milk gives tofu, and fermenting cooked beans gives tempeh, miso and natto. Our guides to edamame, tofu, tempeh, soy milk, miso and natto cover each of those foods.

Unlike most beans, soybeans are also an oilseed. Their fat content is why they are pressed for soybean oil, which our seed oils guide discusses, and why whole soybeans carry more calories than other cooked beans.

Soybean nutrition in USDA data

The table uses the USDA SR Legacy entry for mature soybeans boiled without salt (FDC 174271), per cup (172 g), with percent Daily Value (DV) based on FDA reference values. A version boiled with salt (FDC 174299) lists about 408 milligrams of sodium per cup, 18% of the Daily Value.

A few points stand out. Most of the fat in USDA data is unsaturated: about 8.7 grams polyunsaturated and 3.4 grams monounsaturated per cup. Iron, copper and manganese are high, which is why soybeans appear in our iron foods, copper foods and manganese foods guides. According to the NIH Office of Dietary Supplements, iron from plants is the nonheme form, which is less bioavailable than the heme iron in meat.

Green soybeans tell a different story. The USDA entry for boiled green soybeans (FDC 169283) lists about 254 calories, 22 grams of protein and 31 milligrams of vitamin C per cup (180 g), 34% of the Daily Value, plus more folate than the mature bean. The mature boiled entry lists far less vitamin C.

Soybeans compared with other beans in USDA data

Per 100 grams cooked, USDA data put soybeans in a category of their own among common beans.

Soybeans carry about twice the protein of the other beans and far less carbohydrate, while the other beans are nearly fat-free in USDA data. For the white beans in this table, see our guides to great northern beans and navy beans; for protein comparisons across foods, see high-protein foods. The 2020-2025 Dietary Guidelines list “nuts, seeds, and soy products” as one of the protein foods subgroups.

Roasted soybeans and soy nuts

Roasted soybeans, often sold as soy nuts, are mature soybeans that were soaked and roasted until crunchy. Because the water is gone, every number is concentrated. USDA lists these values per 100 grams:

Two practical notes. Roasted soybeans are calorie dense, close to peanuts and other nuts, so a handful counts for more than it looks. And salted versions vary by brand, so the Nutrition Facts label is the place to check sodium; our low-sodium foods guide explains how to read it. The two USDA roasted entries also list different fiber values, a reminder that database figures are averages from specific samples.

Why dried soybeans are always cooked

Raw mature soybeans are not eaten as they are. A 1994 review in Critical Reviews in Food Science and Nutrition explains that soybeans contain protease (trypsin) inhibitors and lectins, and that both are destroyed by heat. In animal studies, diets of raw soybeans slowed growth and enlarged the pancreas, effects the review attributes mainly to the trypsin inhibitors. A 1995 review in the Journal of Nutrition describes how processing into flours, concentrates and traditional soy foods changes these compounds.

In the kitchen, that means soaking dried soybeans and cooking them until fully tender, which takes longer than most beans. Canned soybeans and the soy foods above are already cooked or processed. Our lectins guide covers what studies show about lectins in beans more broadly.

The same review notes that the sugars that cause gas (oligosaccharides) are relatively heat stable, so cooking does not remove them. NCCIH lists bloating, constipation, diarrhea and nausea as possible side effects of soy. Our gas and bloating guide has general tips.

Are soybeans healthy? What research on soy shows

Whether soybeans are healthy for you depends on your diet as a whole, and the research on soy is large but mixed. The NIH National Center for Complementary and Integrative Health (NCCIH) summarizes it this way, in a fact sheet last updated in April 2025:

• Soy contains isoflavones, which NCCIH describes as compounds similar in structure to estrogen.
• NCCIH says eating soy protein in place of other proteins may have a small effect on cholesterol levels, and that isoflavones on their own may not have the same effect.
• For menopausal hot flashes, NCCIH says any effect of soy protein or isoflavone supplements may be small and study results have not been completely consistent.
• NCCIH notes that observational studies link higher dietary soy with lower breast cancer risk among Asian and Asian-American women, that Western intakes may be too low to show this, and that soy in supplement form has not been shown to reduce breast cancer risk.
• NCCIH says soy use during pregnancy may be unsafe in amounts greater than those commonly found in foods.

In 1999 FDA authorized a health claim linking soy protein to coronary heart disease (21 CFR 101.82). In 2017 FDA proposed revoking it in the Federal Register, citing inconsistent findings in later studies; as of this review no final rule has been published, so the claim technically remains. The honest summary: soybeans are a nutrient-dense legume, and in NCCIH’s summary the isoflavone findings are modest and mostly observational. Our red clover guide covers red clover supplements, a different plant.

Soy allergy and other cautions

• Allergy: FDA lists soybeans as one of the nine major food allergens, and FDA guidance accepts “soybean,” “soy” and “soya” as names for it on labels. Anyone with a soy allergy needs to avoid whole soybeans and soy foods; an allergist can advise on specific products.
• Thyroid medicine: MedlinePlus notes that foods containing soybeans, walnuts and dietary fiber may affect how levothyroxine works. If you take it, ask your clinician or pharmacist how to fit soy foods around it.
• Pregnancy: NCCIH flags amounts above those usual in food, which mainly concerns concentrated soy supplements rather than soy foods.
• Gas: soybeans contain fermentable sugars that a review notes survive cooking; adding beans gradually is a common kitchen approach.

Frequently Asked Questions

Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Last reviewed October 2026.

Related guides: Great Northern Beans: USDA Nutrition, Canned vs Dried, Cooking, Edamame: USDA Nutrition per Cup, Protein, Calories and Benefits, Tofu: USDA Nutrition, Protein, Calories and Types of Tofu.