According to the American Academy of Dermatology (AAD), around 50 million Americans suffer from acne every year. It’s a type of skin condition that affects the hair follicles and sebaceous glands, causing different skin visible issues and pimples.
There can be two types of acne:
- Inflammatory (also called acne vulgaris). The visible signs are pustules (red pimples with puss), nodules (painful and solid pimples deep in the skin), papules (small pink pimples), and cysts. It’s usually painful, difficult to treat, and leads to scarring hyperpigmentation. 
- Non-inflammatory (also called comedonal acne). It includes the formation of whiteheads, blackheads, and small non-inflamed bumps. Usually, people with comedones don’t realize that they actually suffer from acne. 
Nonetheless, this skin condition is not dangerous to our health, it has a significant impact on our self-esteem, confidence, and opinion about ourselves. Often, people with acne feel less attractive, experience anxiety about their appearance, and fear making friends and socializing. And suffering from inflammatory acne has far more negative effects on our mental health than comedonal acne.
The causes for the development of acne vary from genetics, through hormonal disbalance, to the intake of certain medications.  However, there are some indirect factors, which impact the degree of acne development and the severeness of its symptoms, like usage of cosmetic products, and diet. 
And this article will focus exactly on the personal diet as a cause for acne formation.
Foods that may cause acne
A 2015 study that examined the links between Western diet, the formation of comedones and acne inflammation in adolescents, evidenced 3 different food groups that promote acne development. 
Those foods trigger spikes in the blood sugar levels and stimulate high insulin production. They not only increase the production of sebum but change the sebum fatty acids composition, causing inflammation and formation of comedones.
Such foods include processed products with added sugar (cake, sweets, candy, chocolate, packaged sweet foods, sweetened drinks), pastries, white rice, pasta, sweet corn, potatoes, fruit juices, dried fruit. 
Milk and dairy products
The high consumption of milk and dairy products (yogurt, cream, cheese, and butter) is related to increased risk of developing acne, as those foods stimulate the enlargement of the sebaceous glands. Besides, large consumption of cow milk (skimmed and whole) is linked to higher secretion of inflammasome (multi-protein activating inflammation processes) 
The study showed that the consumption of saturated and trans fats irritates and worsens acne symptoms. Such foods include processed and fast foods, butter, cream, palm, and hydrogenated oils, and red meat.
On the contrary, the intake of omega 3 fatty acids was evidenced to neutralize the effect of the saturated and trans fats, and even improve acne conditions. Foods rich in omega 3 are fish, olive oil, and fish oil.
Unfortunately, we cannot get rid of acne with diet change, but we can positively impact it by consuming certain foods in moderation (high glycemic and dairy foods high in saturated and trans fats) while focusing on more suitable ailments like fruits and vegetables with a low glycemic index, and omega 3 rich foods.