The amount of each bile healed and size of Gluttony bonus depends on the foods purity.
Gluttony values for Special Food
This table contains all Gluttony foods which are not Variable. Many of the foods in this table are not well suited for Gluttony with the exception of the Restore foods which can be distinguished by the fact that they give 10 to all Humors, min and max.
Variable Food is mentioned for Gluttony.