The epidemic-like high prevalence of acne of more than 85% of adolescents exposed to westernized life style points to the role of nutritional factors. Insulinotropic foods, especially milk, dairy products and carbohydrates with high glycemic index and smoking lead to pathological exaggeration of already physiologically increased growth factor signaling of puberty. Food-derived growth factors activate the oncogenic phosphoinositide-3-kinase/Akt signaling pathway, which increases androgen receptor transcriptional activity and de-represses FoxO1-suppressed target genes of follicular keratinocyte proliferation and sebaceous lipogenesis. Thus, acne is the visible metabolic syndrome of skin exaggerated by growth factor signaling of westernized malnutrition. These insights allow a new classification of western life style acne as acne alimentaris and provide the rationale for dietary intervention. All efforts should be undertaken to eliminate the insulinotropic effector mechanism of milk in order to reduce the prevalence of acne and even more serious civilization diseases associated with malnutrition-dependent oncogenic signal transduction.