“Packed five lunchboxes and stuck it out for a year” ... Actor Shin Seung-hwan’s “grueling diet” that helped him lose 20 kg [Health Talk]

[Financial News] Actor Shin Seung-hwan, 48, revealed how he managed to lose 20 kg in the past through rigorous diet management.
Shin Seung-hwan appeared on TV Chosun’s “Perfect Life,” which aired on the 4th, and opened up about losing at least 20 kg while filming the movie The Battleship Island. “For almost a year, I packed five lunchboxes containing 100 g of carbohydrates and 150 g of protein and ate them at different times,” he said. “For snacks, I ate only cherry tomatoes and lettuce.” His account showed just how strict he was with himself.

As in the approach Shin Seung-hwan followed, making ample use of foods that are low in calorie density and highly filling is a tried-and-true strategy for preventing overeating and binge eating while dieting.
The tomatoes and lettuce he chose for snacks are especially well-known vegetables suited to dieting. Tomatoes contain only about 20 kcal per 100 g and are at least 90% water, so even a small amount can provide substantial satiety. Lycopene, the key compound that gives tomatoes their red color, acts as a powerful antioxidant, suppressing free radicals in the body and protecting vascular health. Cherry tomatoes in particular contain at least twice as much vitamin A, which supports eye and skin health, as regular fully ripe tomatoes.
Lettuce is also an extremely low-calorie food, with a whole 450 g head containing only around 60–70 kcal. Its abundant insoluble dietary fiber stays in the gastrointestinal tract for a long time, helps prevent sharp rises in blood sugar, and stimulates bowel movements, making it highly effective at preventing constipation, a common problem during dieting.

Trying to split meals into several smaller ones to prevent blood sugar spikes and minimize muscle loss can be positive, but taking this to an extreme for a long time can have the side effect of putting the body into “emergency mode.”
Experts point out that if overly strict dietary restrictions continue, the body’s energy reserves become depleted and the basal metabolic rate drops sharply. When the basal metabolic rate is low, even a slight return to one’s previous food intake makes it inevitable that excess calories will be stored as fat—a phenomenon known as “yo-yo dieting.”
Excessively cutting out carbohydrates and essential fatty acids can lead not only to chronic fatigue and reduced concentration but also to weakened immunity and hormonal imbalances. The medical specialists on the program also voiced concern that overly restrictive diets could disrupt the balance of beneficial gut bacteria and weaken the intestinal barrier, increasing gut-derived toxins (endotoxins) in the bloodstream and promoting systemic inflammation.
The key to healthy weight loss lies not in a “short-term quick fix” but in “habits that can be sustained for life.” Rather than eliminating foods to an extreme, it is essential to follow a gradual weight-loss strategy that maintains a low-carb, high-protein diet with a balanced intake of carbohydrates, protein, and fat, while ensuring that one’s total daily calorie intake does not fall below one’s basal metabolic rate.
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