Legumes (or pulses) are seeds that grow in pods.
Beans, peas, lentils, and peanuts are examples of legumes.
This article will consider beans (including green beans), and to a lesser extent, peas.
Do beans have high levels of starch?
Are beans high in starch compared to other starchy foods?
You’ll see in the table below a comparison between the starch content of the most common types of beans.
|Type of Bean||Grams of starch per 100 grams of bean (raw)|
*Data from all tables taken from the USDA database
Black beans have the highest levels of starch per 100 grams of uncooked beans, at 44.7 grams.
Soybeans are comparatively low in starch, coming in at 13.5 grams of starch per 100 grams.
Compare this with the following table, which analyzes the starch content of the same amount of five of the most commonly eaten types of vegetables.
|Type of vegetable||Grams of starch per 100 grams of vegetable (raw)|
Shockingly, even white potatoes, which are thought of as the starchiest vegetable, still have less than half the amount of starch present in most types of beans!
Compared with vegetables, beans are very high in starch.
How do beans compare with other foods that are high in starch?
|Type of high starch food||Grams of starch per 100 grams of food|
The table above shows comparable levels of starch in white bread and corn tortillas as in most varieties of beans.
White rice takes the cake in starch content, though!
In the final analysis, beans definitely should be considered a food that is high in starch.
However, there is some context that should be considered, as we’ll continue to explore.
Are beans a starch or a protein?
In the table below, you will see a comparison between the starch content and protein content of various types of beans.
|Type of Bean||Grams of starch per 100 grams of bean||Grams of protein|
As you can see, 100 grams of dry beans has a significant amount of protein, comparable to 100 grams of chicken breast.
However, there is a caveat to consider when getting protein from beans.
Most plant proteins are incomplete.
What does “incomplete” mean? Protein is comprised of smaller building blocks, known as amino acids.
Some of these amino acids are non-essential, meaning that we can make them in our bodies.
Some amino acids are essential, meaning we must get them from our diet.
There are nine essential amino acids:
Animal proteins — meat, fish, eggs, and dairy products — are complete proteins, meaning that they supply optimal ratios of all nine essential amino acids.
Most plant proteins, on the other hand, are incomplete proteins, meaning that they are lacking in at least one of the essential amino acids or do not have all nine in optimal ratios.
The exception to this is soy, which is one of the few plant foods that is a complete protein source.
What this means is that you should not rely on beans to supply the totality of your daily protein intake.
For the sake of optimal health, it’s best to rely on animal protein as your primary protein source and use plant proteins as a supplement.
What beans are non-starchy?
Again, see the table below.
This time, I have included green beans, peas, and sugar snap peas at the end of the list for comparison.
|Type of Bean||Grams of starch per 100 grams of bean (raw)|
|Sugar Snap Peas||1.3|
Just like beans, peas, and sugar snap peas are categorized as legumes, or pulses — seeds that grow in pods.
So if you’re looking for legumes that are low in starch, you will want to gravitate towards green beans and different types of peas.
You may wonder why the starch content in green beans and peas is so much lower than in other types of beans.
The difference is in the maturity of the beans at the time they are harvested.
Black beans, kidney beans, pinto beans, and the like are harvested when they are fully mature, which gives the plants more time to store energy (in the form of starch) in the seeds.
Green beans and peas, on the other hand, are harvested before they are fully mature, which means the starch has not had much time to build up.
Do beans contain resistant starch?
The more common type of starch contains more of a molecule known as amylopectin.
It is broken down quickly into glucose by your digestive system, which means that glucose is released more quickly into your bloodstream and a more hefty dose of insulin is required to bring your blood sugar back down to healthy levels.
Resistant starch, on the other hand, also contains a different type of molecule known as amylose.
It is broken down more slowly by your digestive system, which means that it is less likely to spike blood glucose and insulin up to unhealthy levels.
The molecular structure of resistant starch means that it “resists” digestion in the small intestine.
It is therefore passed into the large intestine, where your gut bacteria resides.
Once the resistant starch makes it to the large intestine, bacteria will ferment it and feed on it, releasing certain byproducts that may have beneficial effects on our health.
The most potentially valuable byproduct is known as short-chain fatty acids (SCFAs), which can either be passed into the colon and absorbed by the body, or remain in the large intestine as an energy source for your gut bacteria.
One of the biggest possible benefits of SCFAs is to improve gut health.
SCFAs feed bacteria commonly thought of as “good” for humans and thereby inhibit potentially “bad” bacteria.
Resistant starch has potential benefits for insulin and blood sugar control as well.
Since resistant starch is not digested within the small intestine, it reduces the overall amount of glucose that is released in the bloodstream and thus lowers the requirement for insulin.
This important fact means that getting 30 grams of starch from beans is much different from getting 30 grams of starch from white bread.
The starch from the beans is more likely to be effectively processed by your body with less insulin demand than the starch from the white bread.
Not all starch is created equal — context is important!
What health benefits might there be from consuming beans?
What drawbacks might there be from consuming beans?
Another caveat to consider, if you are relying on beans as a source of vitamins and minerals, is that beans contain high levels of phytic acid.
Phytic acid binds to minerals in the small intestine and reduces the number of minerals actually absorbed by your body.
For example, if you consume 8mg of iron from kidney beans, you likely will not be absorbing the full amount present in the beans due to the phytic acid content.
Incidentally, this is why vegans often have to consume more iron and other minerals than meat-eaters.
The iron found in meat is much more bioavailable and efficiently absorbed than what is found in plants, including beans.
Should you include beans in your diet?
Below are some questions to consider when deciding whether to include beans as part of your regular diet:
- Do you enjoy eating beans?
- How do you feel after eating them?
- If you have digestive distress or a high insulin spike, it may not be worth it to eat them.
- Are you able to enjoy them in responsible amounts, or do they cause you to overeat?
- Remember, managing your body weight always comes back to caloric intake, so managing your weight long-term is dependent on how well you can manage your food intake.
- Are you on a low carb or ketogenic diet?
- If so, beans are most likely not for you, due to their high levels of carbohydrate.
Deciding whether or not to consistently consume any type of food, including beans, means being able to step back and consider the broader context of the food and how it affects your body.
For some people, beans may be a great way to obtain carbohydrates, resistant starch, protein, and vitamins and minerals.
For other people, beans may be a ticket to the restroom.
It’s important to understand your body.