Looks like you’re using v2.4 of the Graph API. See
Declarative Fields
To try to improve performance on mobile networks, Nodes and Edges in v2.4 requires that you explicitly request the field(s) you need for your GET requests. For example,GET /v2.4/me/feed
no longer includes likes and comments by default, butGET /v2.4/me/feed?fields=comments,likes
will return the data. For more details see the docs on how to request specific fields.
To get an idea how to use the so-called field expansion, have a look at