Comparing The Effects Of A Low Fat Diet Versus A Ketogenic Diet On The Motor And Non-Motor Symptoms Of Parkinson's Disease: A Randomized Controlled Trial

This will be a randomized controlled study with 10-40 patients in each of two groups (20-80 patients total). The study will last for ten weeks, although the actual dietary intervention will only be for eight weeks. (1) Diets. Patients will be given a four-week meal plan containing information about their diet, grocery shopping lists for each week, standard meal plan recipes, optional calorie booster recipes, and a cheat diary. Two different diets will be compared. The first diet will be low fat (1758 calories, 42 g fat, 75 g protein, 246 g net carbohydrate per day); by weight, the percentages will be 11% fat versus 62% net carbohydrate. The second diet will be high fat ketogenic (1758 calories, 152 g fat, 75 g protein, 16 g net carbohydrate per day - in other words, a 1.5:1 modified ketogenic diet); by weight, the percentages will be 60% fat versus 6% net carbohydrate. Notably, calorie and protein intake per day will be the same in both diets. The 1758 calories per day and macronutrient ratios given above will be the baseline diet that all participants will be expected to be able to consume. However, some participants will clearly require a higher caloric intake than this. We will provide simple recipes that substantially increase caloric intake but minimally affect protein intake for each group. For the low fat diet several low fat, high net carbohydrate supplemental options (such as fruit shakes) will be provided to the participants. For the ketogenic diet several high fat, low net carbohydrate supplemental options (such as fat shakes) will be provided to the participants. These options will allow for more calories to be consumed while maintaining the relevant fat to net carbohydrate ratio, without significantly increasing protein consumption. We will not ask the patient to maintain a detailed food diary as proof of their sticking to the diet, as previous studies have shown these to be burdensome from the patient perspective. However, we will prescribe a “cheat” diary to each patient such that if they do deviate from the meal plan, they write down the details of the food they ate that was not part of the meal plan. Dietary education and counselling will be provided throughout the study to assist patients with the practical aspects of their diet. We will endeavour to represent both diets as potentially providing health benefits. (2) Assessments. There will be one screening visit one month before the study starts for the following: (1) 0-60 minutes - Lead investigator presentation including explanation of Participant Information Sheet and signing of Consent Form. (2) 60-90 minutes - Parkinson’s nurse assessment on demographics, home situation, comorbidities, Parkinson’s diagnosis, Montreal Cognitive Assessment (MoCA) score, constipation including Bowel Function Index (BFI) score, and medications/medication allergies. (3) 90-150 minutes - Nutrition specialist assessment regarding meal preparation abilities, food preferences/food allergies, and physical status. Information required to calculate body mass index and recommended daily calorie intake will be gathered at the screening visit, but these variables will be calculated after the visit. There will be four clinical visits at Weeks 1, 2, 6, and 10 for the following: (1) 0-15 minutes - Document weight and body mass index, lying and standing blood pressure, and explain and record glucose/ketone monitor. (2) 15-30 minutes - Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) questionnaire. (3) 30-60 minutes - MDS-UPDRS blinded neurologist assessment (non-motor aspects of daily living, motor aspects of daily living, motor examination, motor complications). (4) 60-75 minutes - Bloods (CBC, EUC, lipids, uric acid, CRP). (3) Procedure. Months Before Ads in local and nation-wide Parkinson’s newsletters. Presentations to enhance awareness of study. Month Before Screening visit. Week 1 First clinical visit. Hand out and explain how to use glucose/ketone monitor. Week 2 Second clinical visit. Randomize and hand out meal plans, including cheat diaries. Week 3 Participants commence individual meal plans. Week 4 Continue. Week 5 Continue. Week 6 Third clinical visit. Immediately after the visits are completed, MDS-UPDRS scores will be analyzed to see if one meal plan is superior (participants on one meal plan have significantly improved scores compared to their aggregate baseline scores, or participants on the other meal plan have significantly worse scores compared to their aggregate baseline scores). - If one meal plan is superior, all participants go on the superior meal plan. - Otherwise, all participants stay on their current meal plan. Week 7 Participants commence superior meal plan, or stay on current meal plan. Week 8 Continue. Week 9 Continue. Week 10 Fourth clinical visit. Month After Results relayed to group. *Patients will have 24-hour access to a neurologist and a Parkinson’s nurse throughout the study. *Patients will also be contacted by phone or email every week to see how they are going.