Diet and Cognitive Training in Hematologic Cancer Survivors

The goal of this clinical trial is to examine feasibility of a cognitive intervention program in blood cancer survivors. The main questions it aims to answer are: * is it feasible to combine a ketogenic diet supplementation and online cognitive training in an intervention program * will patients using the combined intervention program have improved cognitive functioning compared to those who don't use it * how long will the intervention programs effects last Participants randomized to the intervention arm will consume an exogenous ketogenic supplementation and use an online cognitive training program for 12 weeks, while waitlist arm functions as a control group and will receive the online cognitive training only after a wait period of 12 weeks. Researchers will compare the intervention and waitlist control groups to see if the intervention improves cognitive functioning.