It really oughtn't be. "Meal" isn't a verb in English (yet); "Let's eat" or "let's eat a meal" are the closest practical translations. I think LiKenun was breaking down the semantic meaning of the words into an English context; the phrase they give is not standard English.
The former is formal, and means to eat a meal, not just anything. Use the latter with your friends.
"Let's eat a meal" is considered incorrect. I realise the direct translation is 'have'. However the meaning is the same
The meaning is not the same. Formality and idiomatics of social class are just as much part of a language as words and conjugations.
I wouldn't consider 'let's have a meal' any different in formality to 'let's eat a meal'. Maybe that's just me or where I am from.
Have a meal is less formal. Most of us don't ever need to speak formally these days though so we're not that familiar with such things.
A better translation for this phrasewould be "let's break bread" or "let's grab a bite" or "let's have some food." "Let's eat" is better translated from English to Korean as 밥목읍시다 or simply 밥목읍시다, with the idea that the food is already prepared and in front of you and everybody's ready to eat - let's eat!
Interesting. I'd like to hear a native Korean speaker's views on this.