Figure 1. Preclinical evidence indicating the effect of a KD on tumor growth and progression. The bar chart shows the number of preclinical studies, which investigated the effect of a KD on different types of cancer. Colors of the bars represent the result of each study as indicated in the color key. Studies on KD and cancer were collected by a literature search covering through the end of 2017. R indicates studies with a calorie-restricted KD; T indicates use of a KD as an adjuvant therapy to classic therapy.