Although a plant-based diet can provide some benefits in Parkinson's disease (PD), no study to date has evaluated the effectiveness of a plant-food diet in the management of the disease. In this pilot study, we compared the effect of a plant-food menu (PFD) and of a omnivorous menu on motor performance of 25 PD patients, 12 in the intervention group (PDi) and 13 in the control group (PDc). After 4 weeks, the PDi group showed a significant reduction (Mann-Whitney test) in the Unified Parkinson's Disease Rating Scale, total score (47.67 vs. 74.46, P = 0.008) and sub-score III motor performances (25.42 vs. 46.46, P = 0.001), and the modified Hoehn and Yahr Staging Scale (1.96 vs. 3.15, P = 0.005). These data suggest that PFD may be useful in the management of PD patients by improving their motor performances. Additional studies are needed in order to confirm these preliminary results.