Korean children have become only a little taller over the past 10 years, but serious obesity has more than doubled.

The Education Ministry on Wednesday announced the results of a study of 84,815 schoolchildren in 764 school nationwide last year to gauge their physical growth and exercise habits.

The average height of a sixth-grade boy is 151.4 cm, 1.2 cm taller than five years ago and 2.3 cm taller than a decade ago, and that of ninth-grade boys is 169.7 cm, 0.8 cm taller than 2010 and 1.2 cm taller than 2005.

But 12th-grade boys have grown slightly shorter on average at 173.5 cm, compared to 173.7 cm in 2010 and 173.6 cm in 2005. The average height of 12th grade girls is 160.9 cm, 0.1 cm shorter than in 2005.

But sixth graders, ninth graders and seniors have all gained weight compared to 10 years ago, and 15.6 percent of the students surveyed weigh more than the average of their age group, up 0.6 percentage points compared to 2014.

The proportion of schoolkids with serious weight problems stands at 1.6 percent, more than twice as high as 10 years ago. There is a higher proportion of obesity in rural areas than in cities.

Meanwhile, the number of youngsters who eat fast food like hamburgers and pizza, increased among all age groups compared to 2014 and gets worse as they grow older. The number who skip breakfast also increases as they get older, while the amount of vegetable and milk consumption falls.

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