Hi, I hope someone who knows English better than me can explain this situation in a way better than me but i will try to explain it to you.
"Yemek" is a pronoun in Turkish as well as a verb. and eat = yemek yemek, meal=yemek.
For example, you can say " I want to eat an apple" ( Bir elma yemek istiyorum)
or
lunch = öğle yemeği , have lunch= öğle yemeği yemek
dinner= akşam yemeği, have dinner= akşam yemeği yemek
In daily We generally don't say that " Öğle yemeği/akşam yemeği yemeye gidiyorum" , We just say instead of both of them " yemek yemeye gidiyorum"
So, Briefly, if you use yemek as a pronoun it is "meal". Otherwise it is eat as a "verb".
you can use it as a verb with a pronoun like that " elma yemek, ekmek yemek, et yemek..."
or you can use it with lunch and dinner like that "öğle yemeği yemek, akşam yemeği yemek..."
Sorry for my English
Have a nice day