"My Skin Aged 5 Years in 7 Days"... Dermatologist Conducts Self-Experiment

Consuming Only Sugar, Refined Carbs, and Dairy
Increased Sebum, Worsened Acne and Atopic Dermatitis

A dermatologist who conducted an experiment by consuming only foods known to be harmful to the skin-such as sugar, refined carbohydrates, and dairy products-for one week found that his skin age increased by as much as five years in a short period of time.

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

On January 15, a video titled "What Happens When a Dermatologist Intentionally Damages Their Skin for 7 Days" was released on the YouTube channel "Pichinnam Lee Seungju," run by dermatologist Lee Seungju.

In the video, Dr. Lee Seungju experimented to observe how his skin would change after consuming, for one week, foods he usually advises his patients to avoid: sugar, refined carbohydrates, dairy products, and greasy instant foods.

From the very first day, the diet was extreme. He consumed castella cake, sweet snacks, low-fat milk, and sweet coffee on an empty stomach. Throughout the week, he continued to eat snacks, sugary drinks, tteokbokki and other street foods, hamburgers, pizza, French fries, instant noodles, and carbonated beverages-a high-sugar, high-fat diet. There were also scenes of him eating pork belly and drinking alcohol.

After several days, immediate changes appeared in his body and skin. Dr. Lee reported facial swelling and severe fatigue, as well as a noticeable increase in facial oiliness and sebum production. New breakouts, including small pimples and inflammatory acne, emerged. His pre-existing atopic dermatitis symptoms also worsened, with itching and inflammation appearing on his legs. He explained that after drinking alcohol, the itching became even more severe due to a histamine reaction triggered by alcohol.

Continuing to consume sweet drinks and late-night snacks until the end of the experiment, he predicted, "Judging by the breakouts that appeared along the way, my skin age will probably come out even older."

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

Dr. Lee stated, "I really want to show these results to my patients," adding, "It makes my advice to pay attention to what you eat even more valid." He emphasized the importance of diet management, noting, "These changes appeared in just one week," and "Proper dietary habits alone can significantly improve your skin condition."