Most companies are happy to promote sustainability so long as it doesn't touch the core business. Not so at Max Burger, a fast-food chain in Sweden that's encouraging customers not to eat its signature product. The decision came after CEO Richard Bergfors commissioned an environmental analysis of his business and found that beef accounted for more than 80% of the company's carbon emissions. To lower this number, the chain cut back on its burger selection and added 30% more non-beef items. It also brought customers into the process by listing the carbon footprint of everything on the menu. The campaign has beefed up sales, with profit margins this year in the double digits.