Burger King revamped its playbook. It's working.

Marcin Golba/NurPhoto via Getty Images This post originally appeared in the Business Insider Today newsletter. You can sign up for Business Insider's daily newsletter here. The burger wars are heating up. Burger King's second-quarter US same-store sales jumped 8.5%, while McDonald's growth lagged at 0.8% and Wendy's went backward, falling 7%. It's not just a win for Burger King's new strategy (more on that in a bit). It shows the burger wars are alive and well, writes BI's Alex Bitter. A bi...