The western diet is usually composed of high-glycemic foods, which have shown in various studies conducted, to produce acne breakouts. These foods with an elevated glycemic index (GI) include industrial sugar and starchy foods such as grains, breads, milk, cereals, and processed foods.

According to some studies, the increase in the level of insulin-like growth factor (IGF-1) and insulin hormone in the human body system, results to the rise of testosterone level in men. Consequently, as testosterone directly affects the secretion of sebaceous glands, increased testosterone brings about an excessive sebum production. The oil or sebum secreted inside the body can block the skin's pores, forming a bacteria-friendly environment and thus promoting acne vulgaris. Also, the previously mentioned hormones cause the overproduction of skin cells, further aggravating the clogging of the pores and nourishing the acne-causing bacteria.

A specific research conducted had discovered that people who only ate natural foods rather than the highly refined foods common in a western diet, showed minor or no acne problems at all.

After that, they conducted the same research on immigrants living in westernized areas. Strangely, these persons, who used to consume only natural foods and did not ever suffered acne before, have developed the disease when they moved to their actual western home and have adapted the western diet including highly refined foods. Also, consumption of western diet in young adolescents causes a sudden rise in the sex hormones, causing an even higher incidence of acne.

Researches have also demonstrated that too much caffeine can also increase the stress hormone levels inside the body. The high amounts of these stress hormones can further trigger the development of acne, or worsen existing acne conditions. The western diet commonly includes high-caffeine beverages, such as soda, tea, and coffee.

Other studies have also shown the relevance of the high amounts of dairy products and red meats in the western diet to the incidence of acne skin problems. This protein diet rises the IGF-1 levels, which, as stated earlier, can also rise testosterone levels, indirectly over stimulating the secretion of sebum, as well.

Studies further demonstrate that dietary modifications oriented to low glycemic carbohydrates, such as vegetables and fruits, have beneficial endocrine effects that are medically efficient in treating acne. Such beneficial endocrine changes keep a healthy skin and a healthy growth of its cells, as well as promote healthy secretion of sebum.

Although there is actually no firm evidence on the relationship of certain foods in the western diet and acne formation, it is still best to regulate the amounts (neither too little nor too much) of whatever kinds of food that we take.