gwajareul neomu manhi meogeumyeon jeonyeoge baega an gopa.

In this sentence, 과자를 actually does have an object particle: 과자 + 를 = 과자를.

So:

• 과자 = snacks / cookies / sweets
• 를 = object particle
• 과자를 = snacks (as the thing being eaten)

The full chunk 과자를 너무 많이 먹으면 means if you eat too many snacks.

과자 usually means snacks, especially packaged snack foods, cookies, crackers, chips, sweets, and similar things.

It is broader than just cookies, so depending on context it can be translated as:

• snacks
• junk food
• cookies / sweets

In this sentence, snacks is the safest general translation.

너무 많이 means too much or too many.

Breakdown:

• 너무 = too, excessively
• 많이 = a lot, much, many

Together, they intensify the amount:

• 많이 먹다 = eat a lot
• 너무 많이 먹다 = eat too much

So 과자를 너무 많이 먹으면 is literally if (you) eat snacks too much.

-으면 / -면 is a conditional ending meaning if or sometimes when.

• 먹다 = to eat
• 먹으면 = if/when (someone) eats

In this sentence, it gives a cause-and-result relationship:

• 과자를 너무 많이 먹으면 = if you eat too many snacks

This structure is very common in Korean for general truths, habits, advice, and consequences.

Korean often leaves out the subject when it is obvious from context.

So this sentence could mean:

• If you eat too many snacks, you won’t be hungry at dinner.
• If I eat too many snacks, I’m not hungry at dinner.
• If people eat too many snacks, they aren’t hungry at dinner.

Without context, it sounds like a general statement: if you eat too many snacks, you won’t be hungry later at dinner.

This omission is very natural in Korean.

Here, 저녁에 uses 에, which marks a time: in the evening / at dinner time.

• 저녁 = evening / dinner
• 저녁에 = in the evening / at dinner time

So 저녁에 배가 안 고파 means (you’re) not hungry in the evening / at dinner time.

If you said 저녁을, that would mean dinner as an object, like in:

• 저녁을 먹다 = eat dinner

But here, 저녁 is not the thing being eaten. It is the time when the result happens.

It can suggest either, and the exact nuance depends on context.

In this sentence, the most natural interpretation is:

• at dinner time
• for dinner
• in the evening

Because the sentence is about eating too many snacks, 저녁에 naturally connects to dinner.

So a very natural English translation is:

• If you eat too many snacks, you won’t be hungry for dinner.

Because 고프다 works like an adjective meaning to be hungry, and in Korean the thing that is hungry is marked with 가/이, not 를/을.

So:

• 배가 고프다 = literally the stomach/belly is hungry
• natural meaning: to be hungry

Breakdown:

• 배 = stomach / belly
• 가 = subject particle
• 고파 = hungry (casual form of 고프다)

So 배가 안 고파 means (I’m/you’re) not hungry.

English says I am hungry, but Korean often says my stomach is hungry.

Both are possible, but 배가 고프다 is very common and natural.

• 고프다 by itself can mean to be hungry
• 배가 고프다 is more explicit and vivid, like my stomach is hungry

Adding 배가 makes the expression feel very standard and everyday.

So:

• 배고파 = I’m hungry / hungry
• 배가 고파 = literally the stomach is hungry, but same overall meaning

Both are common in speech.

고파 is the casual conjugated form of 고프다.

Here’s the pattern:

• dictionary form: 고프다
• casual speech: 고파
• polite speech: 고파요

So:

• 배가 안 고파 = casual
• 배가 안 고파요 = polite
• 배가 안 고프다 = plain dictionary-like or written/plain statement style

The sentence you were given uses a casual, conversational form.

This is because 고프다 is a ㅡ-irregular-looking but actually regular contraction pattern common with -프다 adjectives.

• 고프다
• remove 다 → 고프
• when adding the casual ending, it becomes 고파

So:

• 고프다 → 고파
• 슬프다 → 슬퍼
• 아프다 → 아파

This is a very common pattern to learn.

안 is a simple way to negate verbs and adjectives in everyday Korean.

• 배가 고파 = I’m hungry
• 배가 안 고파 = I’m not hungry

This is very natural in speech.

You could also use -지 않다:

• 배가 고프지 않아
• 배가 고프지 않아요

Those are also correct, but 안 고파 is shorter and more conversational.

It is in casual speech without -요.

That means it would sound natural:

• when talking to friends
• in casual conversation
• in examples or informal explanations

The same sentence in polite speech would be:

• 과자를 너무 많이 먹으면 저녁에 배가 안 고파요.

And in a more formal/plain written style:

• 과자를 너무 많이 먹으면 저녁에 배가 안 고프다.

Korean often uses the present form to express general truths, habits, and predictable results.

So:

• 과자를 너무 많이 먹으면 저녁에 배가 안 고파.

naturally means:

• If you eat too many snacks, you won’t be hungry at dinner.

Even though English often uses will/won’t in this kind of sentence, Korean usually does not need a future marker here.

If you wanted to make the future idea more explicit, you could say:

• 과자를 너무 많이 먹으면 저녁에 배가 안 고플 거야.

But the original sentence is already completely natural.

By default, it sounds like a general rule or common consequence.

It has the feeling of:

• If you eat too many snacks, you’re not hungry at dinner.

That is, this is what happens.

If you wanted to talk about a specific past situation, Korean would usually mark that more clearly with context or different verb forms.

So the original sentence is best understood as a general statement or piece of advice.