Custom Menus, Widgets & Conditional Statements

if you want to show the menus only on child pages then you need to change your conditional statement:

global $post;
//only on children of 269
if ('269' == $post->post_parent){
//menu for Sport & Fitness pages
?>
<div id="seventh" class="widget-area" role="complementary">
        <?php dynamic_sidebar( 'sidebar-7' ); ?>
    </div><!-- #second .widget-area -->
<?php
//only on children of 118
}elseif( '118' == $post->post_parent){
//menu for Eat Smart pages
?>
<div id="eighth" class="widget-area" role="complementary">
    <?php dynamic_sidebar( 'sidebar-8' ); ?>
</div><!-- #second .widget-area -->
<?php
//everything else including parent pages
}else{
//default menu

}