The soup (which has been specified already) is a frequently eaten meal.
If the author knows proper English, then we can assume that using "the" (the definite article) is intentional, and is referring to a specific soup, one which was probably named earlier. (It doesn't have to be a single batch of soup. "Definite" isn't the same as "singular".) However, if this is an imperfect translation or something from someone not good at English, it could be a misuse of "the".
I would guess that if the soup has been introduced already, the word "the" is intended because it's referring to that same soup, and that soup is eaten frequently.
Of course, if the author just doesn't know English that well, then it's hard to know precisely what they mean without greater context, and I got a 404 retrieval error when I tried to visit that URL so I can only guess.