Black beans and rice: a flatter glucose curve, seen one meal at a time

In a randomized crossover trial, 12 healthy women ate 50 g of carbohydrate either as white rice alone or as half a cup of canned black beans with half a cup of white rice. The bean plate gave lower blood glucose at 60, 90 and 120 minutes. Each meal was eaten once, a week apart. Over the full two hours the glucose area only trended lower (p = 0.058), and insulin did not differ. In 17 adults with type 2 diabetes on metformin or diet, black beans with rice lowered the glucose area from 0 to 120 minutes against rice alone. The effect sizes of about 0.4 to 0.5 were given for the bean meals together, not for black beans on their own. These are single meals. We found no long trial of this dish on HbA1c, body weight or disease.

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• Observational data from Brazil link diets higher in rice and beans with more protein, fiber, potassium and iron and less added sugar and saturated fat. — Brazilians aged 10 and older, national Household Budget Survey 2017-2018 (n = 46164) Evidence C source
  Higher protein, fiber, potassium, iron and lower added sugar, total, saturated and trans fat (P trend <= 0.001)
• One cup of black beans and white rice (170 g) provides about 272 calories, 10.2 g protein and 8.5 g fiber. — US survey food composition, per 170 g cup Evidence E source
  Per 100 g: 160 calories, 6.01 g protein, 5 g fiber

What a real portion looks like

• The tested meal that supplied 50 g of available carbohydrate was half a cup of canned black beans with half a cup of steamed long grain white rice. — Test meal protocol for healthy adult women (n = 12) Evidence B source
  1/2 cup black beans + 1/2 cup white rice = 50 g available carbohydrate
• Survey data from Brazil show rice and beans supply about 11 percent and 6 percent of daily energy intake. — Brazilians aged 10 and older, national Household Budget Survey 2017-2018 (n = 46164) Evidence C source
  Rice 10.75% and beans 6.33% of total daily energy

What your body absorbs

• In a randomized crossover trial in 11 active young adults, a rice and black bean meal with 20 g protein raised muscle protein synthesis after exercise, with no significant difference from a nutrient-matched amino acid mix. — Physically active adults, mean age 24, 10 men and 1 woman, one meal after resistance exercise (n = 11) Evidence B source
  MPS 0.057 %/h (rice and beans) vs 0.052 %/h (isolated mix), P = 0.260
• The trial meal of 108 g rice and 143 g canned black beans gave 10 g protein from each and was built as a complementary amino acid pairing. — Physically active young adults, single post-exercise meal (n = 11) Evidence B source
  20 g protein total, 10 g from rice and 10 g from black beans

What it does to your health

• In a randomized crossover trial in 12 healthy women, black beans with white rice lowered blood glucose at 60, 90 and 120 minutes compared with the same carbohydrate load of white rice alone. — Healthy adult women aged 18-65, single test meals a week apart (n = 12) Evidence B source
  Lower glucose vs rice at 60 min (p = 0.026), 90 min (p = 0.001), 120 min (p = 0.024)
• Observational data link higher rice and beans intake in Brazil with 44 percent fewer nutrient inadequacies in the diet. — Brazilians aged 10 and older, national Household Budget Survey 2017-2018 (n = 46164) Evidence C source
  44.49% fewer nutritional inadequacies, highest vs lowest combined intake

Who this works differently for

• In a randomized crossover trial in 17 adults with type 2 diabetes, black, pinto and kidney bean meals with rice lowered glucose at 90 to 150 minutes compared with rice alone. — Adults aged 35-70 with type 2 diabetes on metformin or diet, single test meals (n = 17) Evidence B source
  Lower net glucose at 90, 120 and 150 min vs white rice for all three bean and rice meals
• In adults with type 2 diabetes, black beans and rice lowered the 0-120 minute glucose area compared with rice alone (P = 0.002). — Adults aged 38-70 with type 2 diabetes (9 men, 8 women) (n = 17) Evidence B source
  IAUC 0-120 min p = 0.002, 0-180 min p = 0.007 vs rice; Cohen d 0.431 (0-120) and 0.501 (0-180)
• Observational data in 36,217 Brazilian adolescents link a rice and beans dietary pattern with lower triglycerides and LDL cholesterol. — Brazilian adolescents in the ERICA study (n = 36217) Evidence C source
  Per SD of pattern score: triglycerides -2.24 mg/dL (95% CI -3.57 to -0.91), LDL-c -0.82 (95% CI -1.53 to -0.12)

What is still unknown

• In the same 12-woman trial, the total 2-hour glucose area for black beans and rice only trended lower than rice alone, and insulin area did not differ. — Healthy adult women aged 18-65 (n = 12) Evidence B source
  IAUC glucose vs rice p = 0.058 (trend), insulin iAUC p > 0.05
• In a stable isotope trial in 29 young adults, only about 0.4 percent of the iron in a 100 g cooked common bean meal was absorbed. — Young adult volunteers in Brazil, single 100 g cooked bean meal (n = 29) Evidence B source
  Iron absorption 0.409% (standard beans) vs 0.407% (biofortification target beans), no difference

The bottom line

The protein finding is also one plate. After resistance exercise, 11 active young adults, 10 of them men, ate 3.8 oz (108 g) of rice with 5 oz (143 g) of canned black beans, 20 g of protein split evenly between the two. Muscle protein synthesis rose, and it did not differ significantly from a matched amino acid mix, 0.057 against 0.052 percent per hour. The comparison was with an amino acid mix, never with meat. A US survey recipe puts one cup (170 g) at about 272 calories, 10.2 g of protein and 8.5 g of fiber, figures calculated from a recipe rather than measured in a lab. In Brazil, where the national survey of 46,164 people found rice and beans supplying 10.75 and 6.33 percent of daily energy, eating more of them goes with 44 percent fewer nutrient inadequacies. The same data link higher intake with more fiber, protein, potassium and iron and with less added sugar and saturated fat, and also with more sodium. That is an association, and income and education can drive both sides of it. Among 36,217 Brazilian adolescents, each standard deviation of a rice and beans eating pattern went with triglycerides 2.24 mg/dL lower (95% CI 0.91 to 3.57) and LDL cholesterol 0.82 mg/dL lower (95% CI 0.12 to 1.53), a snapshot of a whole diet pattern. Beans are a weak iron source in practice. In 29 young Brazilian adults only about 0.4 percent of the iron in 3.5 oz (100 g) of cooked common beans was absorbed. Those were common beans, not black beans, and the meal had no rice, so the figure for this dish is still unmeasured. We found no study on allergy, medicines or pregnancy for black beans and rice, so this page has no safety section. That is missing evidence, not a clean record.

Sources

1. bnr-daily-r5-11 · Cross-sectional study
   Among nutritional indicators, higher rice and beans intake was associated with lower total dietary energy and energy density and lower intake of added sugar, total fat, saturated fat and trans fat, while protein, carbohydrates, fibre, Na, potassium and Fe intake were higher (P for linear trend ≤ 0·001).
   Public Health Nutr, 2026 · checked 2026-09-30
2. bnr-daily-r5-13 · Food composition dataset
   Black beans and white rice, FNDDS code 58160154, fdc_id 2708994: Energy 160 KCAL, Protein 6.01 G, Fiber, total dietary 5 G per 100 g; 1 cup 170 g
   USDA FoodData Central survey (FNDDS) 2024-10-31, food code 58160154, fdc_id 2708994 · checked 2026-09-30
3. bnr-daily-r5-03 · Randomized crossover trial
   Bean treatment meals were composed of a 1/2 cup of plain black beans or chickpeas (Bush Brothers & Company, Knoxville, TN, USA) and 15 g of brine from the canned beans (added for flavor) along with 1/2 cup of plain steamed long grain white rice (Great Value, Bentonville, AR, USA).
   Nutrients, 2017 · checked 2026-09-30
4. bnr-daily-r5-09 · Cross-sectional study
   In Brazil, rice and beans accounted for 10·75 % and 6·33 % of total daily energy intake, respectively.
   Public Health Nutr, 2026 · checked 2026-09-30
5. bnr-daily-r5-06 · Randomized crossover trial
   MPS increased from rest but did not differ between COMP (0.057 ± 0.013 %/h) and ISO (0.052 ± 0.013 %/h; P = 0.260; d = 0.4).
   Am J Clin Nutr, 2026 · checked 2026-09-30
6. bnr-daily-r5-07 · Randomized crossover trial
   The meal consisted of 108 g of rice, which was cooked for 12 min in a rice cooker, and 143 g of canned black beans, drained and reheated in a microwave. The meal was served with ∼250 mL of water. The meal was formulated to provide equal amounts of protein from rice (10 g) and beans (10 g), creating a complementary pairing with a more balanced amino acid profile than compared with ingesting either plant protein alone (Table 2).
   Am J Clin Nutr, 2026 · checked 2026-09-30
7. bnr-daily-r5-01 · Randomized crossover trial
   Changes in blood glucose concentrations were significantly different for the black bean meal and the chickpea meal in comparison to rice alone at 60 min (p = 0.026 and p = 0.024), 90 min (p = 0.001 and p = 0.012) and 120 min post prandial (p = 0.024; black bean meal).
   Nutrients, 2017 · checked 2026-09-30
8. bnr-daily-r5-10 · Cross-sectional study
   Higher combined consumption of rice and beans was associated with a 44·49 % reduction in nutritional inadequacies in the diet
   Public Health Nutr, 2026 · checked 2026-09-30
9. bnr-daily-r5-04 · Randomized crossover trial
   Postprandial net glucose values were significantly lower for the three bean/rice treatments in contrast to the rice control at 90, 120 and 150 minutes.
   Nutr J, 2012 · checked 2026-09-30
10. bnr-daily-r5-05 · Randomized crossover trial
    Significant differences were found between the rice control meal and the pinto beans and rice and black beans and rice at 0–120 (P = 0.009 and 0.002) and 0–180 minutes (P = 0.017 and 0.007). The effect sizes (Cohen’s d) for iAUC were determined to be 0.431 for 0–120 minutes and 0.501 for 0–180 minutes.
    Nutr J, 2012 · checked 2026-09-30
11. bnr-daily-r5-12 · Cross-sectional study
    one SD increase in the RRR-DP2 score was associated with the lower mean of triglycerides (β = -2.24, 95% CI -3.57;-0.91), LDL-c (β = -0.82 95% CI -1.53;-0.12), and total cholesterol (β = -1.30 95% CI -1.94;-0.65)
    Eur J Clin Nutr, 2025 · checked 2026-09-30
12. bnr-daily-r5-02 · Randomized crossover trial
    Tukey post hoc tests indicated a significant difference between the rice-only control and the chickpeas and rice meal (p = 0.047) and a trending difference between the rice-only control and the black beans and rice meal (p = 0.058)
    Nutrients, 2017 · checked 2026-09-30
13. bnr-daily-r5-08 · Randomized trial
    Mean iron absorption from the meal with common beans was 0.409% (±0.040%) and mean iron incorporation from the meal with target beans for biofortification 0.407% (±0.038%) and did not differ between the groups.
    Clin Nutr ESPEN, 2018 · checked 2026-09-30