Hi good2gohealth,
It looks like it's being injected right after the closing </html> tag on your site.
Below is the full code:
<link href="http://www.gooddietplanreview.com/plugin-facebox/defunkt-facebox-cbe32e1/src/facebox.css" media="screen" rel="stylesheet" type="text/css"/>
<script src="http://www.gooddietplanreview.com/plugin-facebox/defunkt-facebox-cbe32e1/src/facebox.js" type="text/javascript"></script>
<script type="text/javascript">
jQuery(document).ready(function($) {
$('a[rel=facebox] , div[id=intro_inner] .button_link').facebox({
loadingImage : 'http://www.gooddietplanreview.com/plugin-facebox/defunkt-facebox-cbe32e1/src/loading.gif',
closeImage : 'http://www.gooddietplanreview.com/plugin-facebox/defunkt-facebox-cbe32e1/src/closelabel.png'
});
});
</script>
It also looks like it's pulling images, javascript & CSS files from the folder "plugin-facebox" on your server.
Hope that helps narrows it down.