The annual report, released by the Ministry of Health and Welfare, showed that the proportion of Korean men in their 30s who have developed obesity increased to 46.7 percent last year, from 45.4 percent the year before.
However, the proportion of all obese Korean men dropped by 0.7 percentage points to 34.1 percent from 34.8 percent.
The report also showed that men in their 30s were developing chronic health conditions, including high blood pressure, compared to Koreans in other age groups.
The proportion of Korean men in their 30s who have high cholesterol increased from 10.8 percent to 14.7 percent, while the proportion of Korean men in their 40s and 50s who have the same condition in fact dropped from 2016-2017.
The report also showed that 11.3 percent of Korean men in their 30s had high blood pressure last year, up from 10.3 percent the year before.
The report said Koreans in their 30s were the only age group among all Koreans whose proportion of high blood pressure patients increased from 2016-2017.
When it comes to lifestyle choices, the report showed that 57.9 percent of all Korean men in the age group drink heavily -- defined by drinking five cans of beer or more on the same day -- at least once every month.
It also showed that an increasing number of them are becoming physically inactive; only 18.4 percent said they exercised regularly last year, down from 19.2 percent the year before.
Meanwhile, the number of Korean men who regularly smoke cigarettes marked the record low of 38.1 percent.
Among all Koreans, those who felt that they were in good health accounted for 29.2 percent, and 30.6 percent said they were experiencing severe stress.
By Claire Lee (email@example.com)