An individual that consumes cardboard on a daily basis solely for the purpose of filling their dietry and nutritional needs. Normally someone who can not afford to buy anything of real sustinence.
Josh John went to Greggs and bought some chicken goujons (well, well, well), instead he deciced to eat the box, what a cardboard muncher.
Someone who is addicted to obtaining money and building wealth. A money addict and fanatic. Breadheads often work more than one full-time job, and some even participate in illicit activities to "obtain the bread".