prevent_the_heavy_dance.php

<?php

function feeds_do($name) {
  if (environment_allowed($name, 'feeds', TRUE)) {
    // Do the dance
  }
}

feeds_do('Heavy Import');

settings.php

<?php

$conf = array(
  'environment_override'    => 'my_dev',
  'environment_definitions' => array(
    'my_dev' => array(
      'default' => TRUE,
      'feeds' => array(
        'Heavy Import' => FALSE,
      ),
    ),
  ),
);