The act of consuming large quantities of junkfood carbohydrates. Simular to the act of Carbo-loading which is performed by endurance athletes. Carbo-junking, however is usually performed by over-weight video game players while competing in on-line death-match types of competitions over a number of days.
"Man, I played Call of Duty all weekend long! I sat in on the sofa and was carbo-junking on twinkies, ho-hos and soda the entire time!