The goal of this pilot study is to examine the feasibility and effects of an 18-month intervention diet compared to an active control diet (standard diet) in those living with Parkinson's Disease (PD), without dementia. Research has shown that eating components of Mediterranean diets are associated with a 30% lower risk to develop PD and a 40% lower mortality rate in those living with PD. Diet may influence the gut and microbiomes, thus may affect PD risk and progression. This study will examine how easy it will be to adhere to a certain type of diet for 18 months and what changes may occur in the gut microbiome and in PD symptoms on a specific diet during that time. The study will involve in-person study visits at UBC as well as online diet coaching sessions and online group cooking classes over Zoom. This is a randomized study, meaning that participants will be assigned by chance to either the Mediterranean-style diet group or the standard diet group for the duration of the 18 months. This pilot study will also examine recruitment rates and retention, in order to prepare for a larger future study.