This is most definitely a food-related issue:
Although the United States represents just 5 percent of the global population, it contributes to almost one-third of the world’s weight due to obesity, researchers from the London School of Hygiene and Tropical Medicine concluded in a study released today. The U.S.’s rising obesity rate may lead to a future food scarcity problem, the researchers warned.
Take a peek at this chart:

Click HERE for a larger version.
Our collective heft is akin to adding another half-billion people to the globe. We're weighing it down. Anyone up for a jog?