asa kara onaka ga suite ita noni, isogasikute hirugohan wo taberu zikan ga nakatta.

から means from/since, so 朝から means from the morning onward or since morning.

Here, the speaker is saying that the state of being hungry started in the morning and continued after that.
If you used 朝に, it would simply point to at/in the morning as a time, not emphasize that the condition began then and lasted.

So:

• 朝からお腹がすいていた = I had been hungry since morning
• 朝にお腹がすいた = I got hungry in the morning

The expression お腹がすく is a set phrase meaning to get hungry.

In this expression, お腹 takes が, not を. That is because お腹がすく treats the stomach/hunger state as the thing that becomes empty or is in a hungry state, rather than something you actively do.

So the natural pattern is:

• お腹がすく = to get hungry
• お腹がすいている = to be hungry

Using を here would be unnatural.

すいて is the te-form of すく.

The full form すいていた comes from:

• すく → dictionary form
• すいている → ongoing/resulting state
• すいていた → past form of that state

So お腹がすいていた means not just I became hungry, but I was hungry or I had been hungry.

This is very common in Japanese: a verb plus 〜ている often describes a continuing state.

Because すいた and すいていた focus on slightly different things.

• お腹がすいた = I got hungry / I’m hungry
• お腹がすいていた = I had been hungry / I was hungry

In this sentence, the speaker wants to show that the hunger had continued from the morning.
That makes すいていた a better fit than すいた.

So 朝からお腹がすいていた gives the feeling of an ongoing condition:
I’d been hungry since morning.

のに means although, even though, or despite the fact that.

It connects two ideas that feel contradictory or disappointing:

• 朝からお腹がすいていたのに
• 忙しくて昼ご飯を食べる時間がなかった

So the feeling is:

Even though I had been hungry since morning, I was so busy that I didn’t have time to eat lunch.

Compared with a simple but, のに often carries a stronger sense of frustration, contrast, or unexpectedness.

All three can connect contrasting ideas, but のに often sounds stronger and more emotionally loaded.

• が / けど = neutral contrast, like but
• のに = even though, often with disappointment, frustration, or a sense that the result is contrary to expectation

For example:

• お腹がすいていたけど、食べなかった。
  = I was hungry, but I didn’t eat.
• お腹がすいていたのに、食べられなかった。
  = Even though I was hungry, I couldn’t eat.

In your sentence, のに fits because the speaker is probably unhappy about the outcome.

忙しくて is the te-form of the i-adjective 忙しい.

For i-adjectives, the connector is made like this:

• 忙しい → 忙しくて

This can mean:

• and
• because
• a natural connection between two facts

Here it means something like because I was busy.

So:

• 忙しくて、昼ご飯を食べる時間がなかった
  = I was busy, so I didn’t have time to eat lunch

You cannot say 忙しいで here. That is not the correct way to connect an i-adjective.

昼ご飯を食べる時間 means time to eat lunch.

This is more specific than 昼ご飯の時間, which usually means:

• lunchtime
• the time period for lunch

The sentence is not just saying that lunchtime did not exist.
It is saying the speaker had no available time in which to eat lunch.

So:

• 昼ご飯の時間がなかった = there was no lunch break / no lunchtime
• 昼ご飯を食べる時間がなかった = there was no time to eat lunch

The second one is more precise and natural here.

Because 時間 is the thing that did not exist.

ない often works with が to mark what is absent or nonexistent.

So:

• 時間がない = there is no time
• お金がない = there is no money
• 元気がない = there is no energy

In this sentence:

• 昼ご飯を食べる時間がなかった
  = There was no time to eat lunch

The を belongs to 昼ご飯を食べる, while が marks 時間 as the thing that was lacking.

The subject is understood from context and would usually be I in translation.

Japanese very often omits subjects when they are clear. In a sentence about personal hunger and being too busy to eat lunch, the listener naturally understands that the speaker is talking about themself.

So even though there is no visible 私:

• 朝からお腹がすいていたのに、忙しくて昼ご飯を食べる時間がなかった。
• naturally means I had been hungry since morning, but I was too busy to have time to eat lunch.

This kind of subject omission is extremely common in Japanese.

Literally, お腹 means stomach/belly, but in this expression it corresponds to the English idea of being hungry.

Japanese often expresses hunger through the stomach:

• お腹がすく = to get hungry
• お腹がいっぱい = to be full

So while お腹 literally refers to the stomach area, in normal usage the whole expression simply means to be hungry.

Also, the お in お腹 is an honorific/polite prefix, but this word is extremely common and natural in everyday speech.

Yes, but the nuance would change slightly.

• 昼ご飯を食べる時間がなかった
  = I didn’t have time to eat lunch
• 昼ご飯が食べられなかった
  = I couldn’t eat lunch

The second version is broader. It tells you the result, but not specifically why.
The original sentence is more concrete because it explains that the problem was lack of time.

So the original wording is more detailed and fits well with 忙しくて.

Both mean lunch, but they differ in tone.

• 昼ご飯 = more everyday, conversational
• 昼食 = more formal, written, or stiff in casual conversation

Since the sentence sounds like natural spoken or informal written Japanese, 昼ご飯 is very appropriate.

You may also hear:

• ランチ = lunch
• お昼 = lunch / noon meal, depending on context

Yes, it sounds very natural.

It has several features typical of everyday Japanese:

• omitted subject
• 朝から for since morning
• お腹がすいていた for an ongoing state
• のに for frustrated contrast
• 忙しくて for a cause/reason
• 〜時間がなかった for lack of time

A native speaker could easily say this in conversation.

It breaks down like this:

• 朝から = since morning
• お腹がすいていた = I had been hungry
• のに = even though
• 忙しくて = because I was busy / and I was busy
• 昼ご飯を食べる時間がなかった = there was no time to eat lunch

So the structure is:

[Even though condition A was true], [reason/result B happened].

More literally:

Even though I had been hungry since morning, being busy, I had no time to eat lunch.

Natural English:

Even though I’d been hungry since morning, I was so busy that I didn’t have time to eat lunch.