<qa>  How many older HIV participants will be recruited from the 1917 Clinic?Research Design and Methods DesignSetting: Using an experimental design, a total of 20 older 50 years, stable HIV participants CD4 lymphocyte count 350 cellsmm3 for at least two years and prescribed their current cART regimen for at least six months with self-identified forgetfulness and demonstrate cognitive impairment score on Telephone Interview for Cognitive Status -Modified TICS-M will be recruited from the 1917 clinic data extractedverified using 1917 Clinic database and will be randomly assigned to either the ketogenic diet KD CHO 50 gramsday n 10 or the patient choice diet PCD no dietary restrictionschanges n 10 group for 12 weeks. In addition, the first five n 5 eligible i.e., no metal implants, claustrophobia participants randomized to the experimental group will also be enrolled in an additional magnetic resonance imaging MRI longitudinal study to generate preliminary data regarding the neurological changes associated with cognitive improvement. Previous studies in Alzheimers and Parkinsons disease patients have reported significant cognitive improvement at 28, 45, and 90 days of ketosis. 