Chocolate

Since the 1920s, chocolate has been thought to be an acne trigger, but no consensus has been reached. Several informal studies have connected eating chocolate with a higher chance of getting acne.

In a more recent study, it was shown that eating 25 grams of 99% dark chocolate every day increased the number of acne lesions in acne-prone males after just two weeks. In another study, it was shown that men who took daily capsules of 100% cocoa powder had considerably more acne lesions after a week than those who received a placebo. It is unknown why chocolate could worsen acne, however one study revealed that consuming chocolate increased the immune system's response to bacteria that cause acne, which may help to explain these findings.