Patient description: A 57-year old farmer was diagnosed with Parkinson's disease a year ago. He experiences slowness of movement and tremors. His past medical history is significant for hypertension and hypercholesterolemia. He lives with his wife. They have three children. He used to be active with planting and taking care of their farm animals before his diagnosis. The patient complains of shaking and slow movement. He had difficulty entering through a door, as he was frozen and needed guidance to step in. His handwriting is getting smaller. He is on Levodopa and Trihexyphenidyl. He stated his medications help with shaking and slow movement. But he still has difficulty initiating movements, stiffness and slowness in general. He is an alert and cooperative man who doesn't have any signs of dementia. He doesn't smoke or use any illicit drugs.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Alcoholism Patients with AUD 1. Age 18 years and older. 2. Ability to provide written informed consent as determined by clinical examination and verbal communication. Capacity to consent will be determined by those giving the informed consent. 3. DSM-IV diagnosis of alcohol dependence or alcohol abuse or DSM 5 diagnosis of moderate or severe AUD (established through history and clinical exam). 4. Participants seeking treatment for their AUD (self-report) 5. Minimum 5-year history of heavy drinking (SAMSHA s for heavy drinking: for men 5 or more drinks/day on at least 5 different days per month; and for women 4 or more drinks/day on at least 5 different days per month [self-report]). 6. Alcohol specified as the preferred drug (self-report). 7. NIH employees with an AUD may participate in this study  Unwilling or unable to refrain from use, within 24 hours of MRI and NPT procedures, psychoactive medications or medication that may affect study results (e.g., analgesics containing narcotics, antibiotics [must finish course at least 24 hours prior to a scheduled procedure], antidiarrheal preparations, anti-inflammatory drugs [systemic corticosteroids are exclusionary], antinauseants, cough/cold preparations) (self-report, medical history). The following medications are allowable for entry on this study: analgesics (non-narcotic); antacids; antiasthma agents that are not systemic corticosteroids; antifungal agents for topical use; antihistamines (non-sedating); H2-Blockers/PPI (proton pump inhibitors); laxatives. The use of antihyperlipidemics and/or diuretics are permitted as long as they have been taken for at least 1 month before procedure visits and dose has been stabilized. 2. Current DSM-IV or DSM 5 diagnosis of a major psychiatric disorder (other than alcohol and nicotine use disorders, or substance use disorders that are mild/moderate) that required hospitalization, or that required daily medications for over 4 weeks in the past year (i.e., antidepressants; anticholinergics; antipsychotics; anxiolytics; lithium; psychotropic drugs not otherwise specified (nos) including herbal products (no drugs with psychomotor effects or with anxiolytics, stimulant, antipsychotic, or sedative properties); sedatives/hypnotics). Chronic benzodiazepine use prior to alcohol detox will also be excluded. Note that nicotine and/or caffeine use will not participation. 3. Chronic use of the following medications: analgesics containing narcotics; anorexics (sibuteramine); antianginal agents; antiarrhythmics; antiasthma agents that are systemic corticosteroids; antibiotics; anticoagulants; anticonvulsants; antidiarrheal preparations; antifungal agents (systemic); antihistamines (sedating); antihypertensives (except angiotensin converting enzyme (ACE) inhibitors such as Lisinopril, or Angiotensin receptor blockers (ARB) such as Losartan); anti-inflammatory drugs (systemic); antineoplastics; antiobesity; antivirals (except for treatment of HSV with agents without CNS activity, e.g. acyclovir, ganciclovir, famciclovir, valacyclovir); cough/cold preparations (dextromethorphan preparations, pseudoephedrine); hormones (exceptions: thyroid hormone replacement, oral contraceptives, and estrogen replacement therapy); insulin; and muscle relaxants. 4. Major medical problems that can impact brain function or the use of a ketogenic diet (e.g., epilepsy, diabetes, liver disease, kidney disease, kidney stones (current and/or in the past), chronic metabolic acidosis or a cardiomyopathy) as determined by EKG, history and clinical exam. 5. Clinically significant laboratory findings that could affect brain function (e.g. HIV+). 6. Head trauma with loss of consciousness for more than 30 minutes (self-report, medical history). 7. Pregnant or breast-feeding: Females of childbearing potential, or with tubal ligation, or are post-menopausal and are age 60 or less will undergo a urine pregnancy test and it must be negative to continue participation. Urine pregnancy tests will be repeated on subsequent days of study. (i.e., within 24 hours before study procedures). Females must not be currently breastfeeding. 8. Presence of ferromagnetic objects in the body that are contraindicated for MRI of the head, fear of enclosed spaces, or other standard contraindication to MRI (self-report checklist). 9. Cannot lie comfortably flat on his/her back for up to 2 hours in the MRI scanner (self-report). 10. Body weight > 550 lbs. The MR scanner bed is tested to a weight limit of 0 lbs. 11. Milk or soy allergy (self-report). Note that subjects will not be excluded on initial screening from enrollment onto this study if their breath alcohol test is positive; or if their urine test is positive for drugs. The following guideline will be followed for positive alcohol/drug screens on study procedure days: -If an AUD subject s breath alcohol and/or urine drug screen test is/are positive on study days (i.e., within 24 hours before study procedures except for benzodiazepines during detox, including oxazepam [Serax], the procedures will be postponed and rescheduled to another day. If the urine drug screen is positive for a saliva drug screen will be performed and subject may proceed with MRI/NPT procedures if saliva results for THC are negative. We will not place a limit on rescheduling study days