From Big Eater to Lean Star — How This Top Korean Actor Lost 25kg (With Real Health Tips)

Korean actor Joo Won (37) recently opened up about his dramatic 25kg (55 lbs) weight loss journey — and how cutting carbs played a key role.

Appearing on ENA’s talk show “We Missed You with Choi Hwa-jung and Kim Ho-young” on April 27, Joo Won revealed that before his debut, he weighed around 90kg (198 lbs). But in preparation for his breakout role in the drama 'Bread, Love and Dreams', he managed to slim down to 65kg (143 lbs).

Recalling his past as a big eater, Joo Won shared, “The most effective method for me at the time was cutting out carbohydrates.” When asked if he avoids rice even during dates, he smiled and said, “I usually don’t eat it. And if I do, I make sure to work it off through exercise,” highlighting his commitment to long-term self-discipline.

Many people choose to reduce carbohydrate intake when dieting. Carbs, especially those with a high glycemic index, can rapidly spike blood sugar levels. This triggers insulin production, which not only stores excess glucose as fat but can also lead to sudden crashes in blood sugar — increasing hunger and the risk of overeating.

Insulin also promotes fat storage, making it harder to lose weight when carbohydrate intake is too high.

However, completely eliminating carbohydrates can have negative effects on health. While Joo Won didn’t mention specific side effects, common symptoms of low-carb diets include dizziness, fatigue, and brain fog. Carbohydrates are the body’s primary energy source — when intake is too low, the body turns to protein and fat for fuel, which may weaken muscle function and lead to lethargy.

Additionally, relying on fat as an energy source can produce excessive ketones in the body, which can trigger headaches and other symptoms.

So, what’s the healthy way to manage carbs?

Experts recommend that carbohydrates make up about 55–65% of your total daily energy intake. For those aiming for significant weight loss — like Joo Won — a realistic and safe target is to reduce about 10% of body weight over a six-month period. Along with a balanced diet, combining aerobic exercise and strength training is key to effective and sustainable results.

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