Hawaii has second-lowest adult obesity rate in the nation but that could change dramatically for the worse in 20 years.

That's according to a report released Tuesday by Trust for America's Health and Robert Wood Johnson Foundation.

Hawaii ranks 50th with a 2011 obesity rate of 21.8 percent.  The state with the lowest rate is Colorado at 20.7 percent.

But, the report says the number of obese adults has grown dramatically in Hawaii over the past 15 years and is expected to grow even more in the next 20 years.

The two public health groups warn Hawaii's obesity rate is projected to climb to 51.8 percent in 2030, if the state continues on its current trajectory.

This is the first time the annual report forecasts 2030 adult obesity rates.