Very inconsistent black bean nutrition labels?
Why are the calories and protein of these black beans so different:
From Carral beans, for 100 g:
- 203.4 kcal
- 22.8 g protein
From NCCDB Black Beans, Cooked, for 200 g or 100 g dry:
- 264 kcal
- 17.7 g protein
From FDA's FoodData Central, for 100 g:
- 24.4 g protein (2016 data)
From Nutritionix 0.5 cup, 97 g:
- 331 kcal
- 21 g protein
The Carral and Nutritionix protein isn't that far off. Although, the equivalent cooked vs dried protein is, imo, significantly different. And the ~200 vs ~260 vs ~330 calorie difference is intriguing.
Summary of largest disparities:
- 203 vs 331 kcal
- 17.7 vs 24.4 g protein
Any information on why differences exist will be appreciated. Also, I really love primary sources, so please link academic sources--greatly appreciated!
Answers
-
Four different things could contribute here:
Nutritional variation in the beans themselves - Studies have shown that different varieties and even location of growing, as well as natural variations in the beans themselves, can cause different protein content: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjU_vCLq8fvAhXRJjQIHXP5Dx8QFjAPegQIGhAD&url=https://www.mdpi.com/2073-4395/8/9/166/pdf&usg=AOvVaw18BvFHyQI_cIfCZd0ScPmg
Water content in the final product- As canned beans are a cooked product, different brands may cook them to different degrees and thus show different final calorie counts depending on final water content.
Fiber content - Some nutrition labels can subtract fiber from net carbs and thus reduce calorie counts on the label.
Rounding- Nutrition labels themselves generally contain a margin of error and significant rounding can happen.
That being said, since your concern is around protein content of the bean, with some beans having higher protein but lower overall calories, I'm guessing that relates to the first item with natural bean variation. So, I'd go off the individual brand that you're using, to ensure the most accurate estimate.
