A dermatologist conducted an experiment in which he consumed only foods known to be harmful to the skin-such as sugar, refined carbohydrates, and dairy products-for one week. As a result, his skin age increased by as much as five years in a short period.

On January 15, a video titled "What Happens When a Dermatologist Deliberately Ruins His Skin for 7 Days" was released on the YouTube channel "Pichinnam Lee Seungjoo," which is run by dermatologist Lee Seungjoo.

In the video, dermatologist Lee Seungjoo experimented to see how his skin would change after consuming, for one week, foods he usually advises his patients to avoid-such as sugar, refined carbohydrates, dairy products, and greasy instant foods.

One week of high sugar and high fat diet
Consuming only sugar, refined carbohydrates, and dairy products

Increased sebum, worsened acne and atopic dermatitis
Skin age increased from 31 to 36

Emphasizing the importance of diet management

Skin condition after one week of high sugar and high fat diet experiment. Photo by Lee Seungjoo

The diet was extreme from the very first day of the experiment. He ate castella cake, sweet snacks, drank low-fat milk, and had sweet coffee on an empty stomach. He continued to consume snacks, sugary drinks, Korean street food such as tteokbokki, hamburgers, pizza, French fries, instant noodles, and carbonated beverages, all forming a high sugar and high fat diet. Scenes of eating pork belly and drinking alcohol were also included.

After a few days, immediate changes appeared in both his body and skin. Dr. Lee reported facial swelling and severe fatigue, and a noticeable increase in facial oil and sebum secretion. New cases of whitehead acne and inflammatory skin troubles emerged. His pre-existing atopic dermatitis also worsened, causing itching and inflammatory reactions on his legs. After drinking alcohol, the itching intensified due to a histamine reaction triggered by the alcohol.

Continuing with sweet drinks and late-night snacks until the end of the experiment, he predicted, "Seeing new skin troubles appear here and there, I thought my skin age would come out even older."

Indeed, measurements using a skin diagnostic device showed that his skin age, which was at the level of 31 before the experiment, increased to 36 years-an increase of five years. His skin type changed from combination to oily, and ultraviolet photography clearly showed an increase in sebum and worsening pore condition, especially around the nose.

Dr. Lee said, "I really want to show these results to my patients," adding, "It makes even more sense that I've been telling them to be mindful of what they eat." He continued, "These changes appeared in just one week," and emphasized the importance of diet management, saying, "Proper dietary habits alone can significantly improve skin condition."