One possibility:
“In Belgium, ‘eating like a caveman’ meant chowing down on woolly rhinos and sheep, but in Spain, it meant munching on mushrooms, pine nuts, and moss.”
The main problem with the sentence from the article is that it needs to have two independent clauses joined by a conjunction (”and” or “but”). Instead, it has a compound direct object comprising two complex gerund phrases. One realizes there is something wrong because of the comma which incorrectly separates the two phrases, and one cries out, “Gaaaaaah!” just as one did upon reading Tom the Son’s essay in which he repeatedly plopped prepositions at the ends of his clauses.
“It doesn’t have to be good,” snickered Tom the Son. “It only has to be better than anyone else in the class, including the teacher, could do.” Turkey.
You have the actual skills, when it comes to grammar. I have more of a intuitive feel for it. I couldn’t explain why it seemed wrong, but I knew it made my eyes pinwheel in their sockets. :)