Kang Jae-joon Says He Gained Weight Up to 101 kg... Why Weight Regain Happens After Losing Weight [Health Talk]

[Financial News] Comedian Kang Jae-joon has opened up about the process of regaining weight after losing it.

On the YouTube channel 'With Sean,' in a video released on the 13th, Kang Jae-joon said, "A few months ago, my weight went up to 101 kg, and now I have worked hard to bring it down to 93 kg." He had previously drawn attention for losing 32 kg, but explained that an injury and changes in his lifestyle led to the weight gain again.
Kang Jae-joon also said he would shut down his YouTube channel if he failed to lose 20 kg by Dec. 31 this year. Still, what matters most in weight loss is not short-term numbers but sustainable habits. Intense exercise or extreme dieting may reduce weight temporarily, but injuries or stress can make it hard to keep the weight off.


Kang Jae-joon pointed to an ankle injury after a marathon as the trigger for the rebound. He said that when he weighed in the 90 kg range, he attempted his first full marathon in Hawaii, but his ankle worsened afterward and he was unable to run for a while. Once he stopped exercising, frustration and depression grew. He said he drank alcohol and his routine slipped, causing his weight to rise above 100 kg again.
Pushing long-distance running while carrying a lot of extra weight can place greater strain on the ankles, knees, and hips. Running can improve cardiorespiratory endurance, but people with joint pain or a high degree of obesity are safer starting with low-impact exercise such as walking, indoor cycling, or swimming. If they increase exercise despite pain, the recovery period from injury can become longer, making weight control even more difficult in the meantime.
Weight regain cannot be explained by a lack of willpower alone. When weight is lost too quickly, the body tries to reduce energy expenditure, and appetite control can also become unstable. If someone suddenly cuts back on food and then returns to old eating habits, weight can come back quickly. Add in lack of sleep, drinking, stress, and reduced activity due to injury, and the pace of weight regain can accelerate even more.


Obesity is considered a chronic condition that requires management. The Korea Disease Control and Prevention Agency (KDCA) says obesity can raise the risk of chronic diseases such as diabetes, hypertension, and cardiovascular disease. Domestic obesity treatment guidelines also emphasize that maintaining weight loss is just as important as losing weight in the first place.
The Centers for Disease Control and Prevention (CDC) says gradual weight loss of about 1 to 2 pounds, or roughly 0.5 to 1 kg, per week is more helpful for long-term maintenance. Mayo Clinic also explains that keeping weight off for good requires changes in diet, exercise, sleep, and stress management, not just a temporary diet.
For someone like Kang Jae-joon, who lost weight mainly through exercise, the plan has to be adjusted after an injury. Rather than stopping all exercise because running is no longer possible, it is better to stay active with joint-friendly workouts. Diet should also avoid extremes and instead focus on filling foods such as protein, vegetables, and whole grains.
If the weight has gone back up, there is no need to treat it as a failure. The first step is to identify what caused the recent gain, whether it was injury, drinking, lack of sleep, or a change in eating patterns. When starting to lose weight again, the plan should fit the body’s current condition rather than repeat the same approach used before.


hsg@fnnews.com Han Seung-gon Reporter