The report by the Trust for America's Health shows that nearly a quarter of Californian adults are obese.
That's more than double what it was twenty years ago.
The study defined obesity as an excessively high amount of fat or a body mass index of more than 30.
Despite that figure, California is among the least obese states in the nation.
Southern states have the highest rates.
Colorado and a handful of Northeastern states were in the ten least obese.
The study showed the lower the income and education level, the more likely you are to be overweight.
Weight related health problems are also prevalent in California.
Almost one in ten people here are diabetic.
But there is some good news.
Californians reported more physical activity than in previous years.
And they eat more fruits and veggies than people in other states.