My grammar could be wrong, but it feels like in Cantonese you would typically say something like 食多啲 to mean eat more.
But this Mandarin grammar page says you should usually put 多 before the verb, not after:
In English we like to say things like "eat more" and "drink more beer" and "I need to exercise more." Notice that in every one of these cases, the word "more" (equivalent to this use of 多) comes after the verb in English. In Chinese, it's more natural to put the 多 before the verb.
1) Is my Cantonese grammar wrong?
2) If not, does this mean Cantonese grammar and Mandarin grammar differ regarding 多?