Related Posts in WordPress (Doing many queries)

<?
    function get_related_posts($max_results = 4) {

        # Back up old $posts and $post variables, as get_posts will change those
        global $post, $posts;
        $post_backup = $post;
        $posts_backup = $posts;

        # Get terms from our custom taxonomy
        $terms = get_the_terms($post->ID , 'my-cusotm-taxonomy');

        # Create arrays to hold our already-added posts and the result of this function
        $do_not_duplicate[] = $post->ID;
        $total_matches = array();

        # Make sure there are any taxonomy terms we can loop through.
        if(!empty($terms) AND !is_wp_error($terms)) {

            # Loop over each term and do a new get_posts query for posts matching that term
            foreach ($terms as $term) {
                $posts = get_posts(array(
                    'post_type' => 'news',
                    'custom-tag' => $term->slug,
                    'posts_per_page' => 4,
                    'post__not_in' => $do_not_duplicate,
                ));

                # If any posts are found by that query,
                # add them to $do_not_duplicate, so they won't be added again later,
                # then push them into our $total_matches array
                if($posts) {
                    foreach ($posts as $post) {
                        $do_not_duplicate[] = $post->ID;
                        array_push($total_matches, $post);
                    }
                }
            }

            # If we found any related posts above, show them.
            if (count($total_matches) > 0)
                $total_matches = array_slice($total_matches, 0, $max_results);
        }

        # Restore backups
        $post = $post_backup;
        $posts = $posts_backup;

        # Return result
        return $total_matches;
    }