rss feed for single post, post content is not showing

The site’s rss is working for the root but not for the individual posts, I mean it shows up some info but not the content.

http://www.puremotionfitness.com/nutrition-programs/feed/

what could be the reason for that.? Isn’t that provided by default? Or do I have to use any plugin for that? I can’t find anything online that helped. 🙁