Let's start by keeping things simple.

You can deduct 1/2 of what you actually spend on meals when you are traveling out of town. (70% if you are in certain parts of the transportation industry.)

If you keep your receipts and track your expenses, you can use that.

But keeping all of those receipts when you're out of town is not easy. So as an alternative, you can use some standard meal allowances. That's the numbers you have been looking at from the IRS and GSA. You still need to prove you were out of town, so you'll need the hotel and/or airline receipts. (And if you've got those, how tough is it to stuff a meal receipt right next to them??)

The other angle is to get a slightly larger deduction. Some people don't spend a whole lot on meals when they travel. So they might want to use the standard allowances instead of the actual expense.

That's all on the deduction side of things. But as a person in business for yourself, you might also charge your clients for the meals when you travel. What you charge your client bears no relationship to your deduction. At least not directly.

For meals, you start with the deduction - what you spent - whether that is your actual expense or an allowance amount. From that number, subtract off any reimbursement from your clients. One half of the remainder is not deductible for tax purposes.

--Peter