Actor says he can ‘lose 10 kgs in 3 weeks’ after eating 3 burgers — experts explain why

Koo Sung-hwan / Captured from MBC

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Actor Koo Sung-hwan, 45, has started a diet — but his method raised some eyebrows.

During a recent episode of MBC’s reality show “I Live Alone,” Koo was seen shopping for fall clothes in Itaewon. After struggling to find a size that fit, he confessed, “I’ve gained a lot of weight. I actually weigh 112 kilograms now,” adding that his goal was to “get down to 95 kilograms by the sports day.” His official height is 182 centimeters.

Later in the episode, Koo visited a hamburger shop and devoured three burgers. He laughed, saying, “I’m on a diet, so I only ate about 70 percent,” and confidently added, “Since I skipped the fries, I’ll lose 10 kilograms in three weeks. I’m sure of it.”

His claim sparked curiosity online — can skipping fries really make that big a difference?

Koo Sung-hwan / Captured from MBC

Are hamburgers really diet enemies?

Nutritionists say hamburgers themselves are not absolute “enemies” of dieting. The real problem lies in the combo meal, especially when fries and sugary sodas are added. French fries are high in calories and saturated fats, which can hinder weight loss.

A single burger, on the other hand, contains protein, vegetables and carbohydrates, providing better satiety and nutritional balance than snacks composed solely of carbohydrates such as tteokbokki (spicy simmered rice cakes). Many fitness trainers even suggest that a burger can serve as a relatively complete meal if chosen carefully.

Opting for a low-calorie, high-protein burger can support weight management. However, when patties are fried and topped with sauces or cheese, saturated fat and sodium levels rise sharply, so frequent consumption should be avoided.

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The real problem? Fries and soda

The true culprit in most fast-food meals is the French fries. While potatoes are naturally rich in carbohydrates, deep-frying adds large amounts of saturated and trans fats, turning them into a calorie bomb. A single serving often exceeds healthy fat limits and can negatively affect cardiovascular health.

When paired with soda, a typical burger combo can reach 1,000–1,200 calories, far above the recommended 300-600 kcal per meal for standard diet plans.

By skipping fries and sugary drinks, a single burger alone can be a manageable occasional meal, even during a diet. Replacing fries with low-calorie sides such as salads, coleslaw, or pickles — and choosing water, zero-calorie soda or iced coffee — can help maintain nutritional balance while reducing total calories. Still, experts advise limiting such meals to once a week or less when dieting.

Better side options for balance

Salads, coleslaw, and cucumber pickles are smart alternatives to fries. These sides provide fiber, vitamins and fullness with far fewer calories.

A simple salad with minimal dressing contains about 20-40 calories, while coleslaw averages 100-150 calories per 100 grams, offering less fat and sodium than fries and adding antioxidants from cabbage and carrots. Cucumber pickles are almost calorie-free and enhance freshness and satiety. Thinly sliced apples can also serve as a light, refreshing side.

This article from Kormedi.com, Korea’s top health care and medical portal, is translated by a generative AI system and edited by The Korea Times.