remove body_class filter

add_filter('body_class', 'alc_remove_body_class', 20, 2);
function alc_remove_body_class($wp_classes, $extra_classes) {
if( is_page_template('template-file-name.php') ) :
// List of the classes to remove from the WP generated classes
$remove = array('singular'); //allows for multiple classes to be removed
// Filter the body classes
  foreach( $remove as $val ) {
    if (!in_array($val, $wp_classes)) : continue;
    else:
      foreach($wp_classes as $key => $value) {
      if ($value == $val) unset($wp_classes[$key]);
      }
    endif;
  }
endif;   // Add the extra classes back untouched
return array_merge($wp_classes, (array) $extra_classes);
}