The 40-year-old Kim, known for heavy drinking and smoking, comes from a family with a history of heart problems. Both his father and grandfather, who ruled North Korea before his 2011 inheritance of power, died of heart issues.
Some observers said Kim, who is about 170cm tall and previously weighed 140kg, appeared to have lost a large amount of weight in 2021 but recent state media footage shows he has regained weight.
Kim is a heavy drinker and smoker and comes from a family with a history of heart problems. (AP PHOTO)
The National Intelligence Service (NIS), South Korea's main spy agency, told MPs on Monday in a closed-door briefing that Kim is estimated to weigh about 140kg again and is in a high-risk group for heart disease, according to Lee Seong Kweun, one of the MPs.
Lee said MPs were told that Kim has had symptoms of high blood pressure and diabetes since his early 30s.Â
Another MP, Park Sunwon, said the intelligence service believes Kim's obesity is linked to his drinking, smoking and stress.
Lee and Park quoted the NIS as saying North Korean officials have been trying to get new medications abroad for Kim's suspected high blood pressure and diabetes.
North Korea is one of the most secretive countries in the world and there is virtually no way for outsiders to know Kim's exact health conditions. The NIS also has a varied record in confirming developments in North Korea.
Kim's health is the focus of keen attention outside North Korea since he hasn't formally anointed a successor who would take charge of the country's advancing nuclear arsenal targeting the US and its allies if he was incapacitated.
The NIS maintains its assessment that Kim's preteen daughter, reportedly named Kim Ju Ae, is bolstering her likely status as her father's heir apparent but the NIS said it cannot rule out the possibility that she could be replaced by one of her siblings because she hasn't been officially designated as her father's successor.