खाली पेट नहीं, लेकिन खाना खाने के बाद लेनी है।

खाली पेट literally means empty stomach.

In natural English, this usually means on an empty stomach or before eating anything.

So:

• खाली = empty
• पेट = stomach

As a fixed expression, खाली पेट is very common in medical or dietary instructions.

Yes, it is slightly elliptical, which is very common in spoken Hindi.

Literally, खाली पेट नहीं is just not on an empty stomach.
The full idea is something like:

• इसे खाली पेट नहीं लेना है = It should not be taken on an empty stomach
• or खाली पेट मत लेना = Don’t take it on an empty stomach

Hindi often leaves out words that are obvious from context. If the conversation is already about a medicine, tablet, or dose, खाली पेट नहीं sounds perfectly natural.

They come from the same root, but they are doing different jobs.

• खाना can mean food / a meal
• खाने here is the oblique infinitive form of to eat, used before के बाद

So:

• खाना खाने के बाद = after eating food / after having a meal

This looks repetitive to English speakers, but it is very normal in Hindi.

Both can work, but they are slightly different in feel.

• खाने के बाद = after eating
• खाना खाने के बाद = after eating food / after having a meal

Adding the first खाना makes it a bit more explicit: the speaker means after a meal, not just after putting anything at all in your mouth.

In medical instructions, खाना खाने के बाद is very common.

के बाद means after.

Before postpositions like के बाद, Hindi nouns and infinitives often change into an oblique form. That is why you get:

• खाना → खाने
• खाने के बाद = after eating

This is a normal grammar pattern in Hindi:

• सोने के बाद = after sleeping
• आने के बाद = after coming
• पढ़ने के बाद = after reading/studying

This is one of the most important things to notice in the sentence.

लेनी है is feminine singular, so it agrees with a feminine thing that is understood but not spoken.

Most likely, the omitted word is something like:

• दवा = medicine
• गोली = tablet/pill

Both are feminine, so Hindi uses:

• लेनी है = has to be taken

If the omitted object were masculine, you would get:

• लेना है

For example:

• दवा लेनी है = The medicine has to be taken
• कोर्स लेना है = The course has to be taken

The sentence does not say it explicitly, but from context it is probably something like:

• दवा = medicine
• गोली = pill/tablet

Hindi often leaves out an object if everyone already knows what is being discussed.

So the full sentence might really mean:

• दवा खाली पेट नहीं, लेकिन खाना खाने के बाद लेनी है।
• The medicine should not be taken on an empty stomach, but after eating.

Not exactly. Here लेनी है expresses requirement, instruction, or obligation.

So it means something like:

• has to be taken
• should be taken
• is to be taken

It is not just a plain future like will take.

Compare:

• मैं दवा लूँगा। = I will take the medicine.
• दवा लेनी है। = The medicine has to be taken / should be taken.

In this sentence, it sounds like an instruction, especially a medical one.

The subject is left out because it is understood from context.

Depending on the situation, it could mean:

• you should take it
• he/she should take it
• it is to be taken

Hindi often omits pronouns when they are obvious. In instructions, English often uses you, but Hindi often simply says the action and leaves the subject unstated.

लेकिन means but.

It contrasts two instructions:

• खाली पेट नहीं = not on an empty stomach
• खाना खाने के बाद लेनी है = it should be taken after eating

So the whole sentence sets up a contrast:

• not in one condition
• but yes in another condition

Yes. The sentence is very natural.

Hindi often puts time/condition phrases before the main verb. So the structure is roughly:

• खाली पेट नहीं
• लेकिन
• खाना खाने के बाद
• लेनी है

That is:

• not on an empty stomach
• but
• after eating food
• it has to be taken

This kind of ordering is especially common in instructions.

That is close to the structure, but it is not good English.

A more natural English translation would be:

• Not on an empty stomach, but after eating.
• Don’t take it on an empty stomach; take it after food.
• It should not be taken on an empty stomach, but after a meal.

The exact English wording depends on how explicit you want to be about the hidden object.

It is quite natural in everyday speech, especially in medical advice.

It is not highly formal, but it is also not slangy. The slightly shortened first part, खाली पेट नहीं, makes it sound spoken and practical.

A more fully spelled-out version might be:

• इसे खाली पेट नहीं लेना है, लेकिन खाना खाने के बाद लेनी है।

But in real conversation, Hindi speakers usually shorten things when the context is obvious.