You are a collection of atoms and molecules which in their present configuration is called "you". Before you became "you" these atoms and molecules were part of different configurations and after you stop being "you" these atoms and molecules will be part of other configurations. Remember that all processes in your body are continuous and that atoms and molecules constantly join and leave the configuration of atoms and molecules known as "you".There never was a time when they were ever separate.
Which atoms and molecules is this "spirit" not separate from? When you eat you add new atoms and molecules to your body. Is this "spirit" already present in those atoms and molecules or does this "spirit" join these atoms and molecules as they become part of the assembly that is your body or does this "spirit" ignore them or what exactly happens?