As the environment changes, those countries will have more diet problems, as we do. As in most cultures, food has tremendous social meaning. People can feel like they aren't part of the group if they don't eat like everybody else does. Food also has personal meaning. It can be a person's best friend, and it allows some people to numb out from a difficult world.
Some people look forward during the day to being alone with their food in the evening.
It represents comfort, soothing, and nurturance that may not come from other people. And that leads to certain actions to change the American diet to be more healthy. But if you went back 20 years and said 'I propose we recover money from the tobacco companies to repay states for expenses caused by smoking' or 'we should ban smoking in public places' or 'take Joe Camel off the billboards,' people would have thought you were crazy. Government intrusion, they would have charged. But all that changed as we recognized the overwhelming toll produced by smoking.