The FDA encouraged restaurants to start listing calories on their menus. Restaurants such as McDonalds list the calorie content for everyone to see. While Congress voted to require calories be listed at fast food chains in 2010 the Federal Government has yet to write the rules to carry out the law. This means that any calorie listing is currently voluntarily done by the restaurant 7.
Part of the reason for the weight gain is that people have become less active at work. To try and burn calories companies have come up with standing desks as well as treadmill desks which allow someone to walk in place while they work on their computer.