Obesity rates for American children ages 2 to 5 have been increasing in recent years, according to a study published in the journal Pediatrics. The findings dispute previous reports that obesity has either remained steady or has declined for youth in the United States.

The authors of the study concluded in Pediatrics that they “found no evidence of a decline in obesity prevalence at any age. In contrast, we report a significant increase in severe obesity among children aged 2 to 5 years since the 2013-2014 cycle, a trend that continued upward for many subgroups.”

Their results show that 13.7 percent of preschool-age children were obese in 2016, an increase from 10.7 percent in 2000.

“This is not surprising, necessarily, but it is disheartening,” lead author of the study Asheley Skinner told CNN.

“It tells us that our efforts to improve the health of children is not reaching across the country. We need to improve access to healthy food and physical activity, and do it in a way that recognizes that parents have stressful lives.”

According to the Centers for Disease Control and Prevention, 1 in 6 children and adolescents ages 2 to 19 are obese—three times the rate in the 1970s.