That's when .htaccess expire headers come into their own. Something like a diary needs a very short shelf life. So if the diary was a pdf file:
ExpiresByType application/pdf "access plus 1 day"
Or place the following on the page head placeholder as suggested by Acorn:

<meta http-equiv="Cache-Control" content="no-cache, no-store, must-revalidate" />
<meta http-equiv="Pragma" content="no-cache" />
<meta http-equiv="Expires" content="0" />