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Black beans vs pinto beans: carbs, fiber and net carbs

Full comparison · Protein · Calories · Carbs

Per 3.5 oz (100 g), black beans has 23.7 g of carbohydrate (15 g net) and pinto beans has 26.2 g (17.2 g net).

Net carbs per 3.5 oz (100 g)
Black beans15 gPinto beans17.2 g

Net carbs = total carbohydrate minus fiber.

Black beansPinto beans
Total carbohydrate, 100 g23.7 g26.2 g
Fiber, 100 g8.7 g9 g
Net carbs, 100 g15 g17.2 g
Total sugars, 100 g0.32 g0.34 g
Carbs per serving40.8 g in 1 cup (6.1 oz, 172 g)44.8 g in 1 cup (6 oz, 171 g)
Net carbs per serving25.8 g29.4 g

Net carbs is total carbohydrate minus fiber; it is a common counting convention, not an FDA label term. Total sugars include natural and added sugar; USDA does not separate them for these foods.

What the numbers don't tell you

For a burrito bowl or chili, pick either. Cooked, they sit within 11 calories and a fraction of a gram of protein and fiber of each other per 3.5 oz (100 g), and in a blood sugar trial of both, they behaved alike.

In adults with mildly high cholesterol, 6 weeks of a daily bean mix that included black and pinto beans lowered LDL by about 8.1 mg/dL (0.21 mmol/L) against rice. The mix cannot separate the two. In 17 adults with type 2 diabetes, either bean eaten with rice gave a smaller blood sugar rise than rice alone, a small-to-medium effect, in single meals.

The table hides one thing. Bean protein is less complete than meat: two ounce-equivalents of black beans supplied 3.02 g of essential amino acids against 7.36 g from pork, and less of it reached the blood.

The gas fades. With half a cup of pinto beans a day, fewer than half of adults reported more flatulence in the first week, and 6% by the second, close to the 3 to 11% on bean-free diets. If you cook dry beans, 1 oz dry makes about 2.5 oz (70 g) cooked. Boil them for at least 30 minutes and skip the slow cooker, FDA's advice for a toxin found in many beans and highest in red kidney beans.

Evidence behind this note

  1. Level B In a 6-week RCT in adults with mild hypercholesterolemia, a daily bean mix including black and pinto beans lowered LDL cholesterol by 0.21 versus rice, while peas did not. J Nutr, 2024
  2. Level B In a crossover RCT in 17 adults with type 2 diabetes, pinto bean and black bean meals with rice (50 g available carbohydrate) gave a lower glucose area under the curve than rice alone. Nutr J, 2012
  3. Level B In the same 17-person type 2 diabetes crossover, pinto and black bean rice meals both lowered glucose iAUC versus rice over 0-180 min, with medium effect sizes (d about 0.4 to 0.5). Nutr J, 2012
  4. Level B In two crossover RCTs in 55 young and older adults, two ounce-equivalents of black beans supplied 3.02 g essential amino acids versus 7.36 g from pork and gave lower EAA bioavailability. Nutrients, 2023
  5. Level B Across 3 feeding trials of 1/2 cup beans a day for 8-12 weeks, fewer than 50% reported more flatulence from pinto beans in the first week, and 3-11% did so even on control diets. Nutr J, 2011
  6. Level B In the crossover feeding trials, reports of increased flatulence from half a cup of pinto beans a day fell from 50% of participants in the first week to 6% by the second week. Nutr J, 2011
  7. Level E FDA's Bad Bug Book says the lectin phytohaemagglutinin occurs in many species of beans and is highest in red kidney beans, and advises boiling beans for at least 30 minutes and never cooking them, or dishes containing them, in a slow cooker. FDA, Bad Bug Book: Foodborne Pathogenic Microorganisms and Natural Toxins, 2nd edition, 2012, chapter Phytohaemagglutinin
  8. Level E FNDDS weighs 1 cup of cooked black beans and of cooked pinto beans (from dried, no fat) at 180 g, and 1 oz dry yields 70 g cooked. USDA FNDDS 2021-2023, codes 41102020 and 41104020

Written from the studies and agency guidance we hold for both foods, reviewed by the Bioma editorial system. How we verify.

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Where the numbers come from

Each food is one USDA entry, chosen as it is usually eaten. Other cuts, brands and preparations differ; the links show them. % DV uses FDA Daily Values for adults. How we verify.