Nutritionally, nuts contain a good amount of protein, vitamins and minerals. They are typically quite calorie-dense, containing a high amount of vegetable oils and saturated fats.
Although nuts have more calories, one cup of nuts has around 3x as many as one cup of legumes. Nuts also win out in the fat department, as they contain more fat than legumes.
Much of the calorie-denseness of nuts comes from the oils, which are fats. This is why nuts are a good source of plant-based fats.
It is worth knowing that nuts are high in omega-6 and low in omega-3. Both nuts and legumes are high in protein, legume protein wins out.
The protein in legumes is around 25% of the net calories however with nuts, the protein content is around 10% of the overall calories.
There is some variation within these categories however, for example lentils have a lot more protein than chickpeas.
Although legumes also contain a high amount of proteins, they are a good source of carbohydrates, providing a ton of energy.
Dehiscence is the splitting of a plant formation, releasing its contents. Legumes have this property, which means they are able to open without any external pressure.
Nuts do not have this property, meaning they need to be cracked open.
Legumes and nuts examples
Legumes include any form of beans and peas from the Fabaceae family. Under this umbrella, there are thousands of different legumes.
Pulses fall into this category and are the dried seed of legumes. Some of the most popular pulses are lentils and chickpeas.
Black beans are oval-shaped and are found in many Brazilian and Mexican dishes.
Cannellini beans are white and have the same shape as kidney beans. They have a slightly nutty taste, with a creamy-like quality.
Cannellini beans, if the name didn’t give it away, are often found in Italian dishes, and taste great in soups.
Legumes can be eaten in many ways and can be canned, cooked, frozen, or ground down into flours.
Legumes are incredibly versatile. Lentils are small legume seeds, they are flat, round, and have a different appearance to beans and peas.
With hundreds of varieties of lentils, over 50 of these have been cultivated for consumption.
Lentils can be sold whole, split, with the seed coat, or without. Beluga lentils are said to be the most nutritious, and highest in protein.
Black lentils are often used in Ayurveda to treat illnesses. Although they are called black ‘lentils’, they are in fact a relation to the mung bean.
Bigger than the beluga lentil, black lentils are not such a dark color as beluga lentils, despite their name.
Hazelnuts are round, and well-known for their part to play in the ever-popular chocolate spread, Nutella.
Hazelnuts are rich in monounsaturated fats and vitamins and minerals. Rich in protein and fiber, a small handful provides around 1.3 grams of protein and 1.1 grams of fiber.
Chestnuts are usually found growing on trees or shrubs. Although they can be eaten once harvested, the flavor is fairly bland.
Once stored for a few days, the starches begin to become sugars making them taste a lot better.
Chestnuts can be consumed raw when peeled, they can also be roasted, boiled, steamed, deep-fried, or grilled.
They are an incredibly versatile nut and prepared in numerous ways. Chestnuts are high in carbohydrates instead of oils, which is found in most nuts.
Which nuts are actually legumes?
Nuts grow on trees, whereas peanuts grow in pods underground similar to legumes. The peanut plant is unique as it grows flowers above ground and fruits below.
This is a rare process called geocarpy. When the plant reaches around a foot tall, tentacle-like vines develop from the plant and sink into the ground to form peanuts.
Peanuts are dehiscent, they split open once they have reached maturity. Nuts do not have this quality, which means peanuts are not classified as a true nut.
Peanuts are also not classified as tree nuts like cashews, almonds, and pecans which as you can probably guess are all grown on trees.
Nuts are defined as being a dry fruit with one seed, held inside a hardened shell. Real nuts are fused to these shells and do not naturally crack open.
The nuts that fit this criterion include hazelnuts and chestnuts.
Despite the ‘nut’ part of the word peanut, they are in fact legumes. Peanuts are not far removed from tree nuts, nutritionally speaking.
Tree nuts include walnuts, hazelnuts, and almonds. Comparing the two nutritional profiles, you find that both are high in unsaturated fats and fiber, as well as vitamins and minerals.
Studies have shown a link between the consumption of peanuts or tree nuts and a reduced risk of heart disease compared to people who rarely consume them.
Peanuts are also less expensive than other tree nuts, making them more affordable.
Botanically speaking, peanuts are legumes and not a nut, which is why many people with a peanut allergy are completely fine with tree nuts.
It is because peanuts are not nuts at all, similarly, a person could be allergic to tree nuts and not have a reaction to peanuts.
The botanical and colloquial definitions of nuts appear to be different which is why there may be some confusion around ‘nut’ allergies.
What makes a nut a nut?
According to botanists, a nut is a hard-shelled pod that holds both the fruit and the seed of the plant.
For a nut to be a nut, the fruit does not open to release the seed. Instead, they need to be opened using external force, they cannot open by themselves.
A nut is similar to an achene, which is a dry, one-seeded fruit but nuts are larger, have a hard exterior wall, and have more than one carpel.
Almonds are seeds that are located inside the fleshy fruit of the Prunus dulcis tree. Nuts don’t tend to be wrapped up like this, and so they are classified as a drupe. More on that later.
Cashews are another drupe seed, as are pistachios. If we’re getting super technical, nuts are a sort of fruit.
Fruits grow from a plant’s ovary, which when matured begins to develop a wall around the fruit.
For fruits like apples, this external wall is fleshy, whereas this ‘ovary wall’ for nuts is hard.
Is Walnut a nut or a drupe?
Walnuts are sometimes called “drupaceous nuts”, somewhere in the middle of either classification.
Both mangoes and peaches fall under the definition of a drupe, however, with these fruits, we consume the flesh and not the seed.
This is why it can be a little confusing as to what fruit is classified as what. Many ‘nuts’ are in fact not nuts according to botanists’ definition of what a nut truly is.
This includes almonds, cashews, and pistachios. These are in fact drupes.
In botany, a drupe is an indehiscent fruit where the exterior flesh surrounds a single hardened shell with a seed inside.
Examples of a drupe would be peaches, plums, and cherries. Cashews are a popular drupe.
Unlike other culinary nuts, culinary nuts being ones that in cooking or in general are classified as nuts, cashews do not have a shell.
This is why they cannot be classified as a nut. Instead of an exterior wall, cashews have a lining around the seed that is filled with fluid that has to be removed.
Coconuts also fall under this classification of a drupe as they are the fruit of the coconut palm, making them the drupe of the plant.
Dissimilar to other drupe fruits in the fact that they contain a ton of water.
The difference between nuts and legumes is the number of seeds present, whether or not the shell splits open at maturity, and their nutritional profiles.
The most important distinction is the fact that legumes are indehiscent whereas nuts are dehiscent, meaning they need external pressure to open.
This is why peanuts are classified as legumes, as they are dehiscent.
Walnuts do not fall under either classification, instead, they are considered by many as drupaceous nuts.
This is because they have characteristics of both nuts and drupes so fall somewhere in between.