The IRS allows people who travel for business to deduct their meal expenses from their income. The Per Diem rate is set by the Department of Transportation. The current rate (as of October 1, 2015) is $63 per day in the Continental US and $68 per day while in Canada.You may have heard the amount of the deduction quoted as $50.40.That is because the IRS only allows you to deduct 80% of that rate.he Per Diem rate is set by the Department of Transportation. The current rate (as of October 1, 2015) is $63 per day in the Continental US and $68 per day while in Canada. You may have heard the amount of the deduction quoted as $50.40. That is because the IRS only allows you to deduct 80% of that rate.