For years the acne-diet link has been ignored. However, recent research has clearly shown that poor diet leads to acne and that this is mediated by the same mechanisms which cause diabetes.
A study in 2002 “Acne Vulgaris: a Disease of Western Civilization” was published in the Archives of Dermatology. The researchers studied indigenous tribes of hunter/gatherers, including near Papua New Guinea (Kitavan Islanders) and in the remote jungle of Paraguay (Ache people). Individuals in these groups, including teenagers, showed no signs of acne. It was hypothesized that the lack of acne was related to their low carbohydrate diet. (Since the people there hunt for their food they do not have easy access to carbohydrates and simple sugars as found in fruits, breads, sodas, and candy).
A 2007 study on high-protein, low carb diet and the development of acne studied glucose and insulin levels in the blood on varying diets with the resulting changes on the skin. One group of teenage boys was given foods such as whole grain breads and pasta, beans (legumes) as well as high protein foods. The second group was fed a "typical" teenage diet consisting of white bread, potatoes, and sodas and snacks. After 3 months on the improved diet, the teens showed a significant reduction of acne.
Another study presented at the 2009 American Academy of Dermatology meeting showed that more than 80% of people using the low carb South Beach Diet noticed improvement in their acne within three months of starting the diet.
Finally, chocolate is also a trigger for acne as shown in a study presented at the 2013 American Academy of Dermatology meeting.
The results of these studies indicate a link between high carb diet and acne development.
It is known that high carbohydrate diets lead to increased levels of insulin in the blood, which results in a complex of hormonal changes, including increased levels of IGF-1 (insulin-like growth factor) and androgens (male hormones). Increased IGF-1 levels can lead to the development of blackheads, the precursor of acne lesions. Increased androgen levels increase oil production that results in oily skin and acne lesions. These same increases in insulin levels lead to diabetes and other diseases.
Improving the diet and avoiding carbohydrates alone has improved acne in my patients and in several other studies; however, this takes at least three months or more to reverse the damage as the studies above indicate.