Here are some idiomatic expressions about eating.

Eat out

To eat out is to go out to a restaurant.

If you eat out every day, you will develop some serious health problems.

Eat and run

To eat and run is to eat very quickly because you have to go somewhere else.

If you want to catch that train, you will have to eat and run.

Eat away at someone

When something eats away at you, it bothers you.

I am really worried about my son’s safety. It is eating away at me.

Eat high on the hog

To eat high on the hog is to spend a lot of money on a meal.

If you are wealthy, you can eat high on the hog.

Eat humble pie

When you eat humble pie, you are humiliated.

I was proved wrong and had to eat humble pie in the end.

Eat like a bird

To eat like a bird is to eat very little.

My daughter eats like a bird. I am worried about her health.

Eat like a horse

To eat like a horse is to eat too much.

When he was a kid, he used to eat like a bird.

Eat one’s cake and have it too

She wants to have a flourishing career but hates having to leave her child alone at home. She doesn’t understand that she can’t have her cake and eat it too.