Or any other meal from McDonald's. Reselling as in I buy it and resell it without telling the buyer it's from McDonald's.
First, you would probably be breaching a whole hoard of food safety laws; unless resold immediately bacteria and other nasties will be growing.
Other than that, you can resell it - this is called "retailing". However, you would be required to disclose that what you were selling was a McDonald's Big Mac just like you would need to disclose you were selling a Sony PlayStation. Not disclosing would be the tort of passing off, deceptive and misleading conduct and trade mark violation.