Do I enter business meals at 100% and the program reduces the amount to the allowable 50%?

Adding to  TurboTax KrisD's answer, if you enter your meals expense as an Employee under Job Expenses, you will enter the entire amount, and TurboTax will calculate 50% as your deduction.

But if you are entering your Meals and Entertainment as  a Self-Employed Business Expense, you will enter your expenses in either Meals and entertainment (50% limit) or Meals and entertainment (100% limit).  See the screenshot below. In either case, you would enter the entire amount you spent.

Yes, the program does that for you.