The United States will not be escaping the obesity epidemic crisis anytime soon: Nearly 40% of adults and 19% of youth are obese, the highest rate the country has ever seen in all adults, according to research released Friday by the National Center for Health Statistics.

Since 1999, there has been a staggering rise in the prevalence of obesity, particularly in adults, without any “signs of it slowing down,” according to the study’s lead researcher, Dr. Craig Hales, medical epidemiologist at the US Centers for Disease Control and Prevention.

Youth obesity rates seem to be more stable in recent years. However, it is “too early to tell” what direction youth obesity prevalence will take. At least four more years of data are required to truly understand the direction, Hales said.