The importance of diet in maintaining optimum body health is well recognized. An unhealthy diet has been implicated as a risk factor for several chronic diseases such as cardiovascular disease, hypertension, diabetes and certain cancers. The relationship between diet and periodontitis is not clear. The purpose of this article is to critically review the available literature and to shed new light on the impact of the overall diet on the prevalence and severity of chronic periodontitis in a given population.