Legumes are a staple in diets all around the world and are often relied upon as relatively cheap and shelf-stable sources of nutrition.
They belong to the third largest species of flowering plants in the world, known as the Fabacaea or the Leguminosae family.
What is the legumes family?
As noted earlier, legume plants belong to the third largest species of flowering plants in the world.
This family is incredibly diverse and includes both small herb plants and towering trees (and everything in between).
They have many uses for humans.
Not only are they a pervasive and cheap source of food for both humans and livestock, but they also provide lumber, crop cover for agriculture, and “green manure” to improve soil health.
Are lentils legumes?
Lentils are a part of many cultures’ cuisines, most notably in South Asia, West Asia, and the Mediterranean regions.
Lentils are typically much smaller in size than beans.
Some are cooked in their husks and others are not; the ones with husks tend to remain intact after cooking, while the varieties without husks form a thick purée after cooking.
There are many dishes that can be made from lentils, including soups, curries, salads, and even bread made from lentil flour.
The bulk of the world’s legumes today is produced by Canada and India.
Which bean is the most nutritious?
First, let’s define “nutrient density” in foods.
According to nutrientoptimser.com, which assigns a nutrient density score to various types of foods in its database, nutrient density “tells you how much of the essential minerals, vitamins, amino acids and fatty acids you get per calorie.
It helps you get the nutrients you need without consuming excess energy.”
What this tells you is not simply the absolute value of how many micronutrients and essential macronutrients a food contains, but a comparison of how much nutrition you get for a certain amount of calories.
In other words, a food with a high nutrient density score will give you “more bang for your buck” — a high amount of nutrition (vitamins, minerals, essential amino acids, and/or essential fatty acids) for a relatively low amount of calories.
This is important because modern diets in industrialized nations (I.e., the so-called “Standard American Diet”) are typically very high in energy and relatively low in nutrition.
This is why Dr. Ted Naiman, author of the book The P:E Diet, claims that obesity and obesity-related diseases are caused by an excess of energy (calories) that becomes toxic to the body.
There is a consistent surplus of dietary energy and a low intake of essential nutrients.
With the definition of nutrient density in mind, see the following table comparing the Nutrient Density Scores of six types of beans:
|Type of bean||Nutrient density score|
|Black bean||21/100 (low)|
|Kidney bean||37/100 (good)|
|Green bean||35/100 (good)|
|Pinto bean||31/100 (good)|
Nutrient density score supplied by nutrientoptimiser.com
In this analysis, kidney beans are the most nutrient dense type of bean, compared to black beans, green beans, pinto beans, chickpeas (also known as garbanzo beans), and soybeans.
Green beans and pintos also received a “good” nutrient density score, comparable with kidney beans.
Let’s make a more detailed comparison of the calories, protein, and micronutrient (vitamin and mineral) content of these six types of beans, to understand why kidney beans are the most nutrient dense.
|Type of bean||Nutrient density score||Calories||Protein||Notable vitamin content||Notable mineral content|
|Black bean||21/100 (low)||318||22g||Vitamin B1 (75% RDA), Vitamin B6 (22% RDA)||Copper (93% RDA), Manganese (46% RDA)|
|Kidney bean||37/100 (good)||38||4g||Vitamin B1 (31% RDA), Vitamin C (43% RDA)||Copper (18% RDA)|
|Green bean||35/100 (good)||32||2g||Vitamin A (23% RDA), Vitamin K (36% RDA)||None above 10% RDA|
|Pinto bean||31/100 (good)||76||5g||Vitamin C (24% RDA), Vitamin B1 (19% RDA)||Manganese (16% RDA), Copper (36% RDA)|
|Chickpea||16/100 (low)||364||20g||Vitamin B1 (40% RDA), Vitamin B6 (41% RDA)||Copper (73% RDA), Manganese (926% RDA)|
|Soybean||24/100 (low)||149||13g||Vitamin B5 (19% RDA), Vitamin B6 (28% RDA)||Manganese (31% RDA), Copper (47% RDA)|
Nutritional data based on a 100 gram serving and derived from nutrientoptimser.com
Looking at this comparison, it seems apparent that the kidney beans, green beans, and pinto beans are given a higher nutrient density score because they have significantly fewer calories than the other types.
They have better nutrient density scores in spite of the fact that other types of beans have a higher absolute amount of certain nutrients — for example, black beans have 22 grams of protein, compared with only 4 grams in the same volume of kidney beans.
Chickpeas have an astronomical amount of manganese (926% of the daily value!), but have almost ten times the amount of calories as the equivalent volume of kidney beans.
As with everything in nutrition, context matters.
If your goal is to lose weight, you would do best to focus on highly nutrient dense foods to maximize the nutrition (vitamins, minerals, essential amino acids, and essential fatty acids) in your diet without having to consume a surplus of calories in order to get that nutrition.
But if you’re underweight or highly active, you need more energy in your diet because you carry less of it on your body in the form of body fat.
Protein in black beans
In my opinion, black beans should be considered a supplementary source of protein, not the sole source.
The primary reason for this is related to the issue of nutrient density we discussed above—black beans may provide a decent amount of protein, but it also supplies a significant amount of calories.
Getting at least some of your daily protein intake from lean meat (I.e., chicken breast, fish, lean beef, turkey) is much more calorically efficient.
Just to make the point clear, we stated above that a standard serving size of black beans is half a cup, and it provides 7.6 grams of protein as well as 114 calories.
You can get an equivalent amount of protein from chicken breast while only consuming 43 calories! Black beans contain almost 3 times the amount of calories as chicken breast.
Can I eat black beans every day?
The above questions are crucial to answer when deciding what types of foods you want to make your personal “staple” foods.
Everyone will answer these questions differently, as everyone has different foods that they thrive on and enjoy.
First, determine whether you digest black beans well.
After eating them, do you consistently experience symptoms such as:
- Excessive gas or bloating
- Constipation or diarrhea
- Intestinal pain
- Joint pain
- Skin irritations
- Recurrence of autoimmune symptoms (if you have an autoimmune disease)
If you consistently experience these types of symptoms, you may want to try eliminating black beans from your diet for a time to allow your gut to heal, or you may experiment with reducing the portion size of beans or the frequency with which you eat them.
Second, determine whether you have any dramatic blood sugar swings after eating black beans.
Black beans contain a moderate amount of carbohydrates (20.4 grams per half cup serving), so they have the potential to raise some people’s blood sugar too high for too long after a meal.
However, 7.5 of those 20.4 grams are fiber, so this will slow down the release of blood glucose a bit.
As with everything, different people will experience different reactions to different foods.
To determine your tolerance of black beans, you could get an at-home blood glucose monitor and check your blood sugar levels immediately before and after eating black beans, as well as 2 hours after eating.
You can also monitor your symptoms.
If you feel lethargic after eating, or feel jittery or lightheaded not long after finishing your beans, this may be a sign that your body has a difficult time regulating blood sugar.
Third, think about if you actually enjoy eating black beans!
If you are forcing yourself to eat them because someone on the Internet told you that they are a magical “superfood”, my recommendation would be to relieve yourself of the obligation to eat this food and find another food that is both nutritious and that you actually enjoy eating.
With diets, compliance is king.
If you don’t enjoy your diet, you likely won’t continue with it long-term, and you won’t reach your goals.
Fourth, think about if you can “afford” black beans, from a caloric perspective.
This concept should make sense if you followed the argument about nutrient density earlier in the article.
Think of the caloric content of your foods as a “cost” attached to them.
If you are overweight, you don’t have much “money” to spend, and you have to get the most bang for your buck possible — you need to pay special attention to nutrient density and prefer foods that deliver the highest amounts of nutrients at the lowest amount of calories.
Black beans are rich in nutrition, but there are other types of foods you could choose that have lower caloric levels, if your goal is to lose weight.