Scientists are forecasting that by 2030, 42 percent of the U.S. population will be obese.

This would cost an additional $550 billion in healthcare expenditures, according to the study published by the American Journal of Preventative Medicine.

Despite reports that obesity levels were tapering off, the scientists found that Americans are gaining weight all the time. There's also been a surge in severe obesity, or being overweight enough to reduce your life expectancy by at least seven years.

Given the many caveats listed in the preceding paragraph, the current study forecasts a 33% increase in the prevalence of obesity over the next 2 decades based on extrapolating prior available data and assuming these trends continue into the future. If these forecasts prove accurate, this will further hinder efforts for healthcare cost containment.

Here's a chart showing their projections. The blue line is the previous forecast of 35 percent obesity by 2030. The orange line is what the scientists found by studying trends so far and predictions for the future: