Learn Hardcore Spanish (Latin America): Las lentejas tienen mucha proteína, por eso mi primo las come casi cada día. - Lentils have a lot of protein, that’s why my cousin eats them almost every day.

Lentejas (lentils) is a feminine plural noun, so it uses the article las (the feminine plural form of el/la).
- Singular: la lenteja
- Plural: las lentejas
In Spanish, we usually use a definite article when we talk about a food or thing in general, especially when we mean it as a category:
- Las lentejas son saludables. = Lentils are healthy.
- El café es caro. = Coffee is expensive.
So:
- las lentejas = lentils (as a general category)
- We don’t say los lentejas because the noun is feminine, not masculine.
- We can say just lentejas without an article in some contexts (especially in lists or menus), but for a full sentence making a general statement, las lentejas is the natural choice.

Why is it mucha proteína and not mucho proteína?

Proteína is a feminine singular noun, so any adjective that agrees with it must also be feminine:
- mucha proteína (a lot of protein)
- If it were masculine, it would be mucho.
Agreement rules:
- Masculine singular: mucho queso (a lot of cheese)
- Feminine singular: mucha agua (a lot of water – agua is grammatically feminine even though it uses el in singular)
- Masculine plural: muchos huevos (a lot of eggs)
- Feminine plural: muchas frutas (a lot of fruits)

So mucha proteína is correct because proteína is feminine.

Why is proteína singular? Could you say muchas proteínas?

Mucha proteína treats protein as a substance / mass noun, like water, sugar, or rice in English.
- mucha proteína = a lot of protein (in general, as a nutrient)
You can say muchas proteínas in some contexts, usually when talking about types or molecules of protein in a scientific or technical way:
- Este alimento contiene muchas proteínas diferentes.
  This food contains many different proteins.
In everyday nutritional talk, mucha proteína is the default and most natural way to say it.

What does por eso mean here, and how is it different from porque?

Por eso literally means for that reason or that’s why.
In the sentence:
- Las lentejas tienen mucha proteína, por eso mi primo las come casi cada día.
  = Lentils have a lot of protein, that’s why my cousin eats them almost every day.
Porque means because and introduces a reason clause:
- Mi primo come lentejas casi cada día porque tienen mucha proteína.
  My cousin eats lentils almost every day because they have a lot of protein.
So:
- por eso: connects two sentences, meaning therefore / for that reason / that’s why
- porque: introduces the cause directly, meaning because

The meaning is similar, but the structure and word choice change.

Why is it mi primo las come and not mi primo come las?

In Spanish, object pronouns like lo, la, los, las usually go before the conjugated verb, not after:
- mi primo las come = my cousin eats them
- las = them (referring back to las lentejas)
Mi primo come las is incorrect as a complete sentence, because las cannot stand alone at the end like them in English. If you want to repeat the noun, you normally say:
- Mi primo come las lentejas casi cada día.
So you have two good options:
1. Repeat the noun: Mi primo come las lentejas casi cada día.
2. Use the pronoun: Mi primo las come casi cada día.

The version with las is more natural after the lentils have already been mentioned.

Could you leave out las and just say mi primo come casi cada día?

Not in this context. If you say mi primo come casi cada día, it just means:

My cousin eats almost every day (eats something, not specified).

The direct object – what he eats – disappears.
Because the sentence is clearly talking about lentils, Spanish prefers to refer back to them:

either with the full noun: come las lentejas
or with the pronoun: las come

So here, las is necessary to keep the meaning he eats them (= lentils).

What is las doing grammatically in mi primo las come?

Las is a direct object pronoun for:
- feminine plural nouns that are the direct object of the verb
- It replaces las lentejas.
Pronoun chart for direct objects (people or things):
- lo – him / it (masc. sing.)
- la – her / it (fem. sing.)
- los – them (masc. pl. or mixed group)
- las – them (fem. pl.)

So las in mi primo las come stands for las lentejas and avoids repeating the noun.

Why is it come and not comes or coma?

The verb is comer (to eat). Here we have mi primo = he, third person singular.
Present tense conjugation:
- yo como (I eat)
- tú comes (you eat – informal)
- él / ella / usted come (he / she / you formal eat)
- nosotros comemos (we eat)
- ellos / ellas / ustedes comen (they / you all eat)
So with mi primo (he), the correct form is come:
- mi primo come = my cousin eats
Coma is a subjunctive or a formal command form, not used here.

Why is the present tense (come) used instead of something like está comiendo?

Spanish uses the simple present very naturally to talk about habits and routines:
- Mi primo las come casi cada día.
  My cousin eats them almost every day.
Está comiendo (is eating) focuses on right now, at this moment:
- Mi primo las está comiendo ahora.
  My cousin is eating them now.

Here the context is regular habit, so the simple present come is the correct and most natural choice.

What does casi cada día mean, and is it the same as casi todos los días?

casi cada día = almost every day
casi todos los días = almost every day as well

They are very close in meaning. Both are natural, and both are used in Latin America.

A few nuances:

cada día emphasizes each individual day
todos los días is more like all the days in general

Practically, you can treat them as equivalents in this kind of sentence:

Mi primo las come casi cada día.
Mi primo las come casi todos los días.
Both sound natural.

Could you say mi primo se come las lentejas casi cada día? What’s the difference?

You can say mi primo se come las lentejas casi cada día, but there is a nuance:

comer = to eat (neutral)
- Mi primo come lentejas. = My cousin eats lentils.
comerse (with se) can add a sense of:
- eating the whole portion, or
- a bit more emphasis or informality on the act of eating.

In this specific sentence about a regular habit, come is more neutral and more common.
Se come would sound more like:

He polishes off / really eats up his lentils almost every day.

For a standard textbook-like sentence, come is the best choice.

Why is there a comma before por eso?

The comma separates:

The cause:
- Las lentejas tienen mucha proteína
The consequence:
- por eso mi primo las come casi cada día.

In English we often do the same:

Lentils have a lot of protein, that’s why my cousin eats them almost every day.

Spanish writing conventions are comfortable using a comma before connectors like por eso, pero, sin embargo when they join two closely related clauses. The comma helps show the pause and the logical link.