See section 62 with respect to deductions that are allowable in computing adjusted gross income (i.e., so-called "above-the-line" deductions).
Example. For 1987 A, a Member of Congress, has adjusted gross income of $100,000, and miscellaneous itemized deductions of $10,750 of which $3,750 is for meals, $3,000 is for other living expenses, and $4,000 is for other miscellaneous itemized deductions (none of which is subject to any percentage limitations other than the 2-percent floor of section 67). The amount of A's business meal expenses that are disallowed under section 274(n) is $750 ($3,750 * 20%). The amount of A's miscellaneous itemized deductions that are disallowed under section 67 is $2,000 ($100,000 * 2%). The portion of the amount disallowed under section 67 that is allocated to A's living expenses is $1,200. This portion is equal to the amount of A's deductions for living expenses allowable after the application of section 274(n) and before the application of section 67 ($6,000) multiplied by the ratio of A's total miscellaneous itemized deductions disallowed under section 67 to A's total miscellaneous itemized deductions, determined without regard to the $3,000 limitation of section 162(a) ($2,000/$10,000). Thus, after application of section 274(n) and section 67, A's deduction for living expenses is $4,800 ($6,750-$750-$1,200). However, pursuant to section 162(a), A may deduct only $3,000 of such expenses. The amount of A's other miscellaneous itemized deductions that are disallowed under section 67 is $800 ($4,000 * $2,000/$10,000). Thus, $3,200 ($4,000-$800) of A's miscellaneous itemized deductions (other than deductions for living expenses) are allowable after application of section 67. A's total allowable miscellaneous itemized deductions are $6,200 ($3,000 + $3,200).
26 C.F.R. §1.67-1T