Singer Sung Si-kyung, who recently made headlines after losing 10 kilograms in just over two months, has shared how he is maintaining the result — and eggs sit at the center of his diet.

In a YouTube video posted on Aug. 12 documenting his food tour in Japan, Sung said he now eats “nothing but eggs” for his first meal of the day. The singer, a ballad vocalist who debuted in the early 2000s, has built a large following in recent years through his food-focused YouTube content.

“Even when I don't feel like eating my first meal, I try to make sure I have it. And it even tastes good. That's the fate of someone trying to maintain their weight,” he said.

He added that he had seen advice from a well-known American doctor recommending that adults eat three eggs as their first meal of the day.

During the Tokyo trip, Sung also ate a yogurt containing 10 grams of protein. “Just as there are so many protein drinks available in Korea these days, high-protein foods like this are becoming popular. It's a little dry because it's protein, but it's delicious,” he said.

His observation tracks a broader shift in Korea's food market, where protein-fortified products — from drinks and shakes to snacks and desserts — have spread across convenience store shelves and cafe menus in recent years as consumer interest in high-protein eating has grown.

Sung had previously drawn attention for losing about 10 kilograms in just over two months, reportedly relying heavily on flounder sashimi as part of his diet. Keeping lost weight off over the long term is a well-documented challenge in weight management, so the eating habits maintained after a diet ends can matter as much as the diet itself.

High-protein breakfasts may help control appetite

As in Sung's diet, eating protein-rich foods for breakfast can be beneficial for weight management and overall health. A high-protein breakfast can help people feel full for longer, potentially reducing unnecessary snacking, while also supporting muscle growth and maintenance.

It may also help prevent sharp fluctuations in blood sugar throughout the day, contributing to more stable energy levels.

The benefits have also been examined in scientific research. A study presented at Nutrition 2026, the annual meeting of the American Society for Nutrition, found that participants who ate a protein-rich breakfast consumed significantly less added sugar and fewer sweet foods throughout the day than those who did not. The findings suggest that simply changing breakfast may positively influence eating habits for the rest of the day.

Eggs, in particular, are widely regarded as a nutrient-dense source of protein. One egg contains about 6 grams of high-quality protein, along with B vitamins and a moderate amount of fat. Adequate protein intake can help preserve muscle mass during weight loss and, in turn, help maintain metabolic health.

A study published in the International Journal of Obesity also examined the potential weight-loss benefits of eggs. Researchers divided adults with obesity into two groups and had them eat either eggs or bagels for breakfast for eight weeks. Although both groups consumed the same number of calories per day, the egg group experienced a 65 percent greater reduction in body weight and a 61 percent greater reduction in BMI than the bagel group.

The findings suggest that the greater satiety provided by the protein-rich egg breakfast may have helped participants reduce their overall food intake compared with a carbohydrate-heavy breakfast.

Protein yogurt can be a good choice, but watch the sugar

The protein yogurt Sung ate alongside his eggs can also be a useful addition to a weight-management diet. One potential benefit of yogurt is its probiotics — live microorganisms produced or maintained through fermentation. Regular consumption of yogurt containing probiotics may support the balance of beneficial bacteria in the gut and help maintain the intestinal barrier.

However, consumers should check the sugar content of commercially available yogurt. Despite being marketed as a health food, some flavored yogurt products contain 10 grams or more of added sugars from ingredients such as sugar or syrup.

Products advertised as containing natural honey also deserve careful consideration, as the sugars they contain still contribute to total sugar intake.

Sugary foods and beverages can produce a rapid rise in blood glucose, particularly when the sugars are readily digestible. This can stimulate insulin secretion and, when excessive calorie intake is sustained, contribute to weight gain. For this reason, people choosing yogurt for breakfast should check the nutrition label and opt for products with little or no added sugar.

The same caution applies to Greek yogurt, another popular high-protein option. Some full-fat varieties can contain 10 grams or more of fat per serving, including a significant amount of saturated fat. For people trying to improve their overall diet, choosing lower-fat varieties or moderating portion sizes may be advisable.

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.