The twist wasn’t obvious to me when I saw it. I quite liked the movie.

When I was a kid there was a Norwegian children movie called "The hunt for the kidney stone" where a kid travels into the body of his sick grandpa to find out what's wrong with him (kidney stone). After the movie I asked my mom what kidney stones are, and where they come from. "You can get them if you eat too much salt, for example" she says, and after that I was TERRIFIED every time my parents would put salt on anything.

Meanwhile my dog has access to clean fresh water, yet insists on drinking from the dirtiest puddles outside