For the second day of Pie Week, we present the mandatory spending pie. Mandatory spending is part of total federal spending, which we explored in yesterday's total federal spending pie.

Spending for mandatory programs is not determined by lawmakers during their yearly process for passing the federal budget. Instead, mandatory programs like food stamps and Medicare have certain eligibility criteria; anyone who meets them receives benefits from the program. Want to know more about mandatory spending? Check out Federal Budget 101. And visit the Budget Matters blog again tomorrow, when we'll have another pie for your enjoyment.