Eating qat is haraam, because it makes people listless and distracts them from remembering Allaah and from praying. It is not permissible to delay the prayer from its proper time or to fail to pray in congregation. These are evil actions which result from eating qat, and they are all haraam actions. Hence eating qat is emphatically forbidden.
And Allaah is the Source of strength. May Allaah send blessings and peace upon our Prophet Muhammad and upon his family and companions.