The British Association of Dermatologists says there is ‘little evidence that any foods cause acne, such as chocolate and fast food’. Yet a new book by two dermatologists – Perfectly Clear: The Perfect Guide to Clear Skin – says that restricting refined processed carbohydrates (such as sugar, white flour and white pasta) can reduce acne. Research from the British Medical Journal also shows that a diet high in dairy, particularly skimmed milk, can increase severity of acne. Greasy foods in general? Not so much.

Acne is caused by oil-producing glands in the skin getting blocked, leading to blackheads, redness and spots with pus where bacteria infiltrate the area. Production of oil (sebum) is increased by sex hormones, hence the appearance of acne at adolescence. Acne is definitely not caused by dirty skin. However, diet may have a role, albeit a small one. So should you modify your diet if you get spots?

Milk may increase acne because cow feed includes sex hormones – these then stimulate sebum production and foster spot formation. Since foods with a high glycemic index (HGI) – those that make blood glucose rise quickly – increase the release of sex hormones, it’s not clear why skimmed milk is a villain. Some researchers think that drinking it makes people eat more HGI foods than if they drank a fattier variety.
The Guardian