SEOUL— Kim Jong Un has shed some weight. Much of North Korea is now in tears.

Photographed recently at Workers’ Party meetings, Mr. Kim looks slimmer, prompting the regime’s carefully choreographed state media to run interviews with ordinary North Korean citizens. They voiced concerns about the country’s leader held across the impoverished nation.

“We were most heartbroken when we saw our dear General Secretary had become emaciated,” said a middle-aged North Korea man, wearing a straw hat and referring to one of Mr. Kim’s official titles. “Tears came out naturally.”

No topic inside highly censored North Korea is more verboten than the health of the ruling Kim leader. South Korean officials have recently said they noticed no significant change to Mr. Kim’s health. Those remarks followed a November spy-agency assessment that the dictator, despite chronic smoking and obesity, appeared to be fine.

But Pyongyang watchers sense Mr. Kim’s skimpier figure has potential political undertones, providing stark imagery that the Supreme Leader is suffering alongside his citizens who face food shortages and an economic crisis. Mr. Kim recently acknowledged North Korea’s food situation, and he urged the country’s leaders to resolve shortages resulting from lower agricultural output, which he attributed largely to crop failures caused by last summer’s typhoons.

“We can’t rule out that Mr. Kim listened to his doctor and lost weight,” said Nam Sung-wook, a professor of North Korean studies at South Korea’s Korea University. “His regime, though, is trying to create public sympathy for him through such interviews as the economic situation worsens,” he said.

Mr. Kim, believed to be around 5-foot-6, tips the scales at an estimated 310 to 330 pounds, Seoul’s spy agency has said. That’s nearly double the normal weight range for someone Mr. Kim’s height.

After his father, Kim Jong Il, died nearly a decade ago, Kim Jong Un, then 27 years old, was a relatively svelte 198 pounds in his first year leading North Korea. Since then, he has gained about 14 pounds annually, Seoul’s spy agency said.

“ ‘In North Korea, being overweight is a sign of authority and power.’ ”

— Kim Chun-sig, a former South Korea official who oversaw North Korea policy

Mr. Kim’s weight gain was to help him better resemble his grandfather, Kim regime observers say, as it arouses nostalgia of better times among the North Korean public. Kim Il Sung, the country’s father and Mr. Kim’s grandfather, never shed the pounds he gained after the 1950-53 Korean War before his death in 1994.

Whatever is behind Mr. Kim’s recent weight loss, some South Korean experts say he is unlikely to have shed the pounds by design. “In North Korea, being overweight is a sign of authority and power,” said Kim Chun-sig, a former senior Seoul official who oversaw North Korea policy. “That’s why Kim Jong Un gained weight in the first place and why he is unlikely to have lost weight on purpose.”

The health of Mr. Kim—and his predecessors—has long attracted global speculation, made even more complicated by the insularity of the information-repressed regime. Last year, a nearly three-week absence from public view ignited a global guessing game over whether Mr. Kim was alive or dead. He later emerged, smiling and smoking, at a factory opening.

The attention isn’t unfounded. A sudden demise of a Kim ruler, if it were to trigger internal revolt or political chaos, could mean the U.S., its allies and China would have to prepare for a sudden flow of refugees. It could also require a potential deployment of troops to prevent Pyongyang’s nuclear weapons from falling under control of a rogue replacement.

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Intelligence officials should still try to gain more information on why Mr. Kim has lost weight—and how much he has dropped, said Cho Tae-yong, South Korea’s former vice foreign minister and now a conservative lawmaker who sits on the Seoul legislature’s intelligence committee.

“Kim Jong Un’s health in itself is a sign of North Korea’s internal situation,” Mr. Cho said.

North Korea’s state media rarely comments on the health of the ruling Kim. In 2014, Kim Jong Un had been absent for weeks and reappeared walking with a cane. State media remarked that Mr. Kim hadn’t been feeling well.

In 2008, North Korean state media had remained silent about a mysterious ailment of his father, Kim Jong Il. Details emerged after a French neurosurgeon, who said he secretly treated the North Korean leader, gave media interviews mentioning Mr. Kim had suffered a stroke.

State media didn’t provide much detail about Kim Jong Il’s medical condition until his 2011 death. Mr. Kim died of a heart attack while on a train, state media reported.

Write to Andrew Jeong at andrew.jeong@wsj.com