Custom Yoast Variables

function retrieve_the_content( $var1 ) {
       global $post;
       return strip_tags($post->post_content);
}

function yoast_custom_meta_variables() {
       wpseo_register_var_replacement( '%%the_content%%', 'retrieve_the_content', 'basic', 'Replaced with The Content' );
}
add_action( 'wpseo_register_extra_replacements', 'yoast_custom_meta_variables' );