There are three main things that I recommend you avoid eating if you are dealing with acne. 

First of all, dairy. Hormones (including growth hormones) in dairy, particularly A1 casein dairy, contribute largely to the cause of acne. Large controlled trials have found cow’s milk increased both the number of people who got acne and its severity.

Other acne-triggering dietary culprits include processed fats like trans fats, which increase arachidonic acid levels and compete with omega-3 fats in the body, leading to more inflammation and acne.

I also, highly recommend avoiding sugar if you have acne. Sugar raises insulin levels, which promotes inflammation in general, causing acne. Large randomized prospective controlled trials (the gold standard of medical research) found people who had higher sugar intake and a high glycemic load diet (more bread, rice, cereal, pasta, sugar, and flour products of all kinds) had significantly more acne.

Full episode on The Doctor’s Farmacy.