For some time now we have been telling you about the global trend toward obesity, even in low and middle-income countries.  The World Health Organization says billions of people are getting fat. By 2015, the WHO says approximately 2.5 billion people will be overweight and 700 million of them will be considered obese. Gaining, losing and then regaining weight is a common problem.  But a U.S. study shows one of the best ways to keep that weight off permanently is to work with someone who motivates you.  VOA's Melinda Smith explains.