More food research -- if you are preparing or eating food, you will prepare and EAT more if it came in a larger container.  So, if you buy a big container of spaghetti because it will save you money, you will fix and eat more of it than if you had bought a smaller container...by about 20%.  Tests done on junk food are even worse -- a study on M&Ms found people given the larger container ate twice as much.  So,  it seems that as a general rule, buying the smaller package might be better in the end, even though it seems like the bigger one might save a trip to the grocery, save money, etc.