When you think about picking a career that’ll help make the world a better place, do you think of working at the largest fast food company in the world?

You may not, but that’s indeed what Bob Langert spent his career doing. The former McDonald’s executive was at the forefront of many of the decisions the restaurant behemoth made relating to social responsibility, from retiring styrofoam containers to paying tomato pickers more to improving farm animal welfare.

Now retired, Bob has a new book out about his career spent trying to help the fast food chain do better. It’s a candid look at where he thinks his former employer got it right and where he believes they came up short.

If you’ve ever wondered how a major corporation makes decisions about improving its sustainability footprint, this interview is for you.