Chicken breast or tofu: more protein against more calcium

In a meta-analysis of the trials the FDA itself listed, 41 of them with LDL data, a median 25 g a day of soy protein lowered LDL cholesterol by 4.76 mg/dL (95% CI 2.80 to 6.71) over a median 6 weeks, against control proteins that were often dairy. That soy protein was an ingredient, which is a step away from a block of tofu. US labels may still say that 25 g of soy protein a day, in a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. The FDA proposed revoking that claim in 2017 and has not issued a final rule. We found one trial that put the two foods side by side. In 16 healthy young Chinese men, tofu eaten before white rice gave a lower glucose and insulin rise than chicken breast, in a single meal with no absolute differences given in the abstract. On the plate, 3.5 oz (100 g) of roasted chicken breast gives 31 g of protein and 85 mg of cholesterol. Firm tofu set with calcium sulfate gives 17 g of protein, no cholesterol and 683 mg of calcium, one USDA record each, and that calcium comes from the coagulant.

How much is actually in it

• British tables give grilled skinless chicken breast 148 calories and 32.0 g of protein per 3.5 oz (100 g), against 73 calories and 8.1 g of protein for steamed tofu. — CoFID 2021 records 18-323 (chicken breast, grilled without skin, meat only) and 13-570 (tofu, soya bean, steamed) (n = 2 records) Evidence E source
  Per 100 g, chicken against tofu: energy 148 against 73 calories, protein 32.0 against 8.1 g, fat 2.2 against 4.2 g, cholesterol 94 against 0 mg

What a real portion looks like

• Per 100 g, roasted chicken breast gives 31 g of protein and 85 mg of cholesterol, while firm calcium-set tofu gives 17 g of protein, no cholesterol and 683 mg of calcium. — Two USDA SR Legacy records: chicken breast, meat only, roasted (FDC 171477) and firm tofu prepared with calcium sulfate (FDC 172475), published 2019-04-01 (n = 2 records) Evidence E source
  Per 100 g, chicken against tofu: energy 165 against 144 calories, protein 31.02 against 17.27 g, fat 3.57 against 8.72 g, saturated fat 1.01 against 1.261 g, cholesterol 85 against 0 mg, calcium 15 against 683 mg, iron 1.04 against 2.66 mg, fiber 0 against 2.3 g; reference portions 1 cup diced chicken 140 g, half cup tofu 126 g

What your body absorbs

• In a randomized crossover trial in 16 healthy men, a tofu preload before white rice gave a lower early glucose and insulin response than a chicken preload, while both blunted glucose against rice alone. — Healthy Chinese men eating soya tofu, chicken breast, a 50/50 mix, or nothing before white rice, measured over 3 hours (n = 16) Evidence B source
  Soya + Rice: significantly lower incremental peak and iAUC 0-60 min glucose and lower insulin iAUC 0-180 min than Chicken + Rice; higher GLP-1, GIP and triglyceride responses with soya
• In a small randomized crossover trial in 14 vegetarian women eating 6.1 oz (173 g) of tofu a day for 30 days, adding 303 mg of vitamin C raised hemoglobin more than tofu alone. — Premenopausal lacto-ovo vegetarian women, 6 oz (173 g) tofu daily with or without 303 mg vitamin C, two 30-day periods (n = 14) Evidence B source
  Greater hemoglobin increase with tofu plus vitamin C (p = 0.0361 and p = 0.009 in the two periods); no difference in serum ferritin change

What it does to your health

• Pooled observational data link eating about 0.95 oz (27 g) of tofu a day with an 18% lower risk of cardiovascular disease. — 29 cohort and case-control studies, 16,521 type 2 diabetes and 54,213 cardiovascular events, follow-up 2.5 to 24 years, mostly in Asia (n = 29 studies) Evidence C source
  Tofu 26.7 g/day and CVD TRR 0.82 (95% CI 0.74 to 0.92); highest against lowest soy and T2D TRR 0.83 (95% CI 0.74 to 0.93)

Safety, limits and interactions

• In 142 oral challenges with 3.5 oz (100 g) of silken tofu in young Japanese children suspected of soy allergy, 38.7% reacted and 7 had anaphylaxis treated with epinephrine. — 125 children, mean age 2.8 years, challenged with 100 g silken tofu at one Japanese center, 2004 to 2010 (n = 142 challenges) Evidence C source
  Positive challenge 38.7%; skin symptoms 81.8%, respiratory 50.9%; 7 anaphylactic reactions
• A survey of 209 retail skinless boneless chicken breasts from at least eight US states found Campylobacter on 1.9%, at concentrations below detection limits. — 209 retail skinless boneless chicken breasts processed in at least eight US states (n = 209) Evidence C source
  Campylobacter prevalence 1.9% by enrichment; not detected by spread plating or viability qPCR
• The FDA label for levothyroxine says soybean flour may bind the drug and cut its absorption from the gut. Tofu is a soy food but the label does not name it. — People taking levothyroxine sodium tablets (n = -) Evidence E source
  Direction only: soybean flour may bind levothyroxine and reduce its absorption; no size, no amount of soy, no timing in this section

What people believe that the data does not support

• A meta-analysis of the trials on the FDA's own list, 41 of them with LDL data, found that a median 25 g a day of soy protein for a median 6 weeks lowered LDL cholesterol by 4.76 mg/dL against non-soy protein. — Adults with baseline LDL cholesterol 110 to 201 mg/dL in 46 trials identified by the FDA, 41 with LDL data (n = 41 trials) Evidence A source
  LDL cholesterol -4.76 mg/dL (95% CI -6.71 to -2.80); total cholesterol -6.41 mg/dL (95% CI -9.30 to -3.52); no dose-response
• In a double blind randomized crossover trial in 45 adults with raised cholesterol, 4 weeks of Kori-tofu did not improve cardiometabolic markers more than a whey protein control. — Adults aged 40 to 70 years with mildly elevated cholesterol, 4 weeks Kori-tofu or whey protein with a 4 week washout (n = 45) Evidence B source
  LDL, HDL, HbA1c and systolic pressure fell within both arms; only adiponectin change differed between treatments
• US labeling law still allows foods with soy protein to say that 25 g of soy protein a day, in a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. — Foods sold in the United States carrying the authorized soy protein health claim Evidence E source
  Authorized model claim at 25 g soy protein a day; FDA proposed revoking it in 2017 and the final rule is still pending
• Observational studies pooled in 2024 associate high tofu intake with a 22% lower total cancer risk. — 52 studies (17 cohort, 35 case-control) on soy product consumption and cancer (n = 52 studies) Evidence C source
  High tofu intake and total cancer RR 0.78 (95% CI 0.70 to 0.86); each 61 g/day of tofu associated with 12% lower risk

Who this works differently for

• In a 12 week randomized trial in 93 older women, adding steamed chicken breast to resistance training kept arterial stiffness from rising, while training alone raised pulse wave velocity by 4.9%. — Women aged about 67 years randomized to control, extra chicken breast, resistance training, or training plus chicken breast for 12 weeks (n = 93) Evidence B source
  CfPWV change: training alone +4.9%, training plus chicken -2.4%, control -2.5%; muscle thickness and strength improved with training in both training arms

The bottom line

Which tofu you buy changes the numbers. British tables list steamed tofu at 73 calories and 8.1 g of protein per 3.5 oz (100 g), against 148 calories and 32.0 g for grilled skinless chicken breast, and the gap from the US firm tofu figure comes from the type of tofu. Firm tofu also brings 2.66 mg of iron and 2.3 g of fiber per 3.5 oz (100 g), against 1.04 mg and none in chicken. In a small crossover trial in 14 vegetarian women eating 6.1 oz (173 g) of tofu a day for 30 days, adding 303 mg of vitamin C raised hemoglobin more than tofu alone, with no difference in ferritin and no effect size reported. One tofu product has been tested against a protein control. In a double blind crossover trial in 45 adults aged 40 to 70 with mildly raised cholesterol, 4 weeks of Kori-tofu did not improve cardiometabolic markers more than whey protein. The observational data lean toward tofu. Pooled studies, 26 of 29 from Asia, link about 0.95 oz (27 g) of tofu a day with an 18% lower risk of cardiovascular disease (TRR 0.82, 95% CI 0.74 to 0.92). Across 52 studies, mostly case-control, high tofu intake is associated with a 22% lower total cancer risk (RR 0.78, 95% CI 0.70 to 0.86), an association rather than proof that tofu prevents cancer. It also gives no support to the fear that tofu raises cancer risk. For chicken, a 12 week trial in 93 women aged about 67 found that resistance training alone raised arterial stiffness by 4.9%. With steamed chicken breast added to the training it changed by -2.4%, close to the -2.5% in controls, and the trial had no plant protein arm. Two cautions come from the cards. In 142 challenges with 3.5 oz (100 g) of silken tofu in Japanese children with a mean age of 2.8 years suspected of soy allergy, 38.7% reacted and 7 had anaphylaxis treated with epinephrine, at a single center. A survey of 209 retail skinless boneless chicken breasts from at least eight US states found Campylobacter on 1.9%, at levels below the lab's counting limit, which is not the same as safe: raw chicken can still carry it. We found no long-term study comparing the two foods on any hard outcome.

Sources

1. cbtf-daily-r3-02 · food composition dataset
   Chicken, breast, grilled without skin, meat only (CoFID 18-323) per 100 g: energy 148 kcal; protein 32.0 g; fat 2.2 g; cholesterol 94.0 mg ... Tofu, soya bean, steamed (CoFID 13-570) per 100 g: energy 73 kcal; protein 8.1 g; fat 4.2 g; cholesterol 0.0 mg
   CoFID 2021, Public Health England, codes 18-323 and 13-570 (OGL v3.0) · checked 2026-10-02
2. cbtf-daily-r3-01 · food composition dataset
   Chicken, broilers or fryers, breast, meat only, cooked, roasted (FDC 171477, SR Legacy) per 100 g: energy 165 kcal; protein 31.02 g; fat 3.57 g; saturated fat 1.01 g; cholesterol 85.0 mg; calcium 15.0 mg; iron 1.04 mg; fiber 0.0 g; portion 1 cup, chopped or diced 140 g ... Tofu, raw, firm, prepared with calcium sulfate (FDC 172475) per 100 g: energy 144 kcal; protein 17.27 g; fat 8.72 g; saturated fat 1.261 g; cholesterol 0.0 mg; calcium 683.0 mg; iron 2.66 mg; fiber 2.3 g; portion 0.5 cup 126 g
   USDA FoodData Central, SR Legacy, records 171477 and 172475 · checked 2026-10-02
3. cbtf-daily-r3-03 · randomized crossover trial
   Soya + Rice treatment induced a significantly lower incremental peak and incremental area under curve (iAUC) (0-60 min) glucose level compared with Chicken + Rice. The postprandial insulin response (incremental peak, iAUC 0-180 min) was significantly lower after Soya + Rice than Chicken + Rice group.
   Eur J Nutr, 2025 · checked 2026-10-02
4. cbtf-daily-r3-04 · randomized crossover trial
   There was no significant difference in the change in serum ferritin levels between the T and TO groups over the first and second experimental periods. In conclusion, bioavailability of iron from tofu is enhanced by supplementation with ascorbic acid.
   Plant Foods Hum Nutr, 2002 · checked 2026-10-02
5. cbtf-daily-r3-08 · meta-analysis of observational studies
   A daily intake of 26.7 g of tofu reduced CVDs risk by 18% (TRR = 0.82, 95% CI: 0.74-0.92) and 11.1 g of natto lowered the risk of CVDs by 17% (TRR = 0.83, 95% CI: 0.78-0.89), especially stroke.
   Nutrients, 2023 · checked 2026-10-02
6. cbtf-daily-r3-10 · retrospective cohort
   The positive rate for the challenge test was 38.7%. Induced symptoms were observed in the skin (81.8%), respiratory system (50.9%), and gastrointestinal system/mucosal membrane/anaphylaxis (12.7%). Intramuscular epinephrine was administered to all 7 patients who experienced an anaphylactic reaction.
   Allergol Int, 2016 · checked 2026-10-02
7. cbtf-daily-r3-11 · prevalence survey
   Culture-based enrichment yielded isolates for 15 samples, with whole genome sequencing identifying isolates from four samples as C. jejuni, eight samples as Acinetobacter spp., one as Micrococcus luteus, and one as Escherichia coli, resulting in a 1.9% prevalence of Campylobacter on retail skinless boneless chicken breast.
   J Food Prot, 2025 · checked 2026-10-02
8. sf-soylev-r5-7 · agency advice
   Soybean flour, cottonseed meal, walnuts, and dietary fiber may bind and decrease the absorption of levothyroxine sodium from the gastrointestinal tract.
   Levothyroxine sodium tablets, FDA-approved label, section 7.9, effective 2026-03-24 · checked 2026-10-08
9. cbtf-daily-r3-05 · meta-analysis of randomized trials
   Soy protein at a median dose of 25 g/d during a median follow-up of 6 wk decreased LDL cholesterol by 4.76 mg/dL (95% CI: -6.71, -2.80 mg/dL, P < 0.0001; I2 = 55%, P < 0.0001) and decreased TC by 6.41 mg/dL (95% CI: -9.30, -3.52 mg/dL, P < 0.0001; I2 = 74%, P < 0.0001) compared with non-soy protein controls.
   J Nutr, 2019 · checked 2026-10-02
10. cbtf-daily-r3-06 · randomized crossover trial
    Due to the lack of significant effects as compared to control, there is, however, currently no substantiating evidence to claim that Kori-tofu has beneficial effects on cardiometabolic health.
    Nutrients, 2022 · checked 2026-10-02
11. cbtf-daily-r3-07 · regulation
    Diets low in saturated fat and cholesterol that include 25 grams of soy protein a day may reduce the risk of heart disease.
    21 CFR 101.82, Health claims: Soy protein and risk of coronary heart disease (FDA) · checked 2026-10-02
12. cbtf-daily-r3-09 · meta-analysis of observational studies
    High consumption of total soy products (RR: 0.69; 95% CI: 0.60, 0.80), tofu (RR: 0.78; 95% CI: 0.70, 0.86), and soymilk (RR: 0.75; 95% CI: 0.60, 0.93) were associated with reduced total cancer risk.
    Nutrients, 2024 · checked 2026-10-02
13. cbtf-daily-r3-12 · randomized controlled trial
    Percent changes in carotid-femoral pulse wave velocity (cfPWV) and carotid β-stiffness (indices of arterial stiffness), and circulating angiotensin II (a vasoconstrictor peptide hormone) levels via each intervention were significantly higher in the RT group (4.9 ± 12.7%, 13.8 ± 13.5%, 94.9 ± 132.7%, respectively), as compared with the CON group (-2.5 ± 5.9%, 0.2 ± 8.1%, 21.2 ± 79.3%, respectively) (P < 0.05). Of note, no significant differences in the cfPWV, carotid β-stiffness, and circulating angiotensin II levels between the RT + HP (-2.4 ± 9.3%, 2.4 ± 10.3%, -5.7 ± 29.6%, respectively) and CON groups were observed.
    J Cachexia Sarcopenia Muscle, 2025 · checked 2026-10-02