Kim is believed to be about 5 foot 7 inches tall (1.7 metres), so at more than 300 pounds, the North Korean leader, assessed to be in his mid-thirties, would be considered severely obese and potentially at risk for various health problems.

Last April, during an unexplained absence, there was rampant speculation that Kim was in “grave danger” after an operation, that he was dead, or in a coma or brain-dead.

It turns out Kim was actually alive and well, but he definitely has not been the picture of perfect health. The following photo is one of Kim in late February or early March of this year.

The North Korean leader appeared on state-run KCTV on June 5, as NK News senior analytic correspondent Colin Zwirko noted on Twitter, and expert North Korea watchers pointed out that he looks to have shed some weight.

NK News conducted an analysis of multiple state media photos of Kim wearing his US$12,000 Portofino Automatic watch made by IWC Schaffhausen, noticing that the length of the strap past the buckle appears longer in recent photos than it did last November, indicating that he was able to wear it tighter on his wrist.

Though this type of analysis is not always an exact science, state media images and video have provided a wealth of information about developments within North Korea, especially the country’s nuclear warhead and missile programmes.

“You have to use all available resources,” Su Mi Terry, said North Korea expert at the Centre for Strategic and International Studies. “For a very difficult country like North Korea, where they tightly control information, you have to do what you can.”

In recent photos, Kim’s face looks a little smaller, and his clothes appear to fit a little more loosely than they do in some other pictures from past events.

“On the surface, noticeable weight loss may not mean much,” Michael Brodka, a US military intelligence officer in South Korea, told NK News, “but it can provide clues to other information that intelligence collectors look for.

“It may be a simple matter of a healthy lifestyle change or a more complex issue. Right now, we do not know, but it raises enough serious questions that we must pay attention to events over the next couple of months to find out.”

Kim Jong-un’s weight and related health concerns, as well as his reported affinity for chain smoking cigarettes and drinking heavily, have long been considered risk factors for the North Korean regime, and they have fuelled a lot of speculation about succession in the event of a sudden death.

“Succession is very unclear if something were to happen to Kim Jong-un,” said Terry. “We know he’s unhealthy. So we need to care.”

She said that leadership health is probably “one of the most important indicators” of regime stability. For North Korea, she said, “Kim Jong-un’s health is the biggest wild card.”

This article originally appeared on Business Insider.