Weight Gain in Pediatric Leukemia Survivors

Patient Eligibility Criteria: * Must have a diagnosis of ALL (T or B cell). * Must be receiving standard of care maintenance chemotherapy or be within 6 months of having concluded maintenance chemotherapy at the time of enrollment. * Must be at least 6 years of age and no older than 18 years of age at time of enrollment. * Must be able to speak and understand English. * Must have a caregiver who is participating in this study. * Must be able to perform some level of exercise (e.g., a brisk walk for at least five minutes) as determined by self-report. * Must not have severe developmental delay/intellectual disabilities (such as Trisomy32, severe presentations of autism spectrum disorder) or significant mental illness (such as active suicidal ideation, psychotic symptoms, manic or hypomanic episodes, or severe substance use disorder) that may interfere with ability to participate in modified Family Based Therapy (FBT). * Patients 10 and older must have a negative SCOFF screen for disordered eating (Score of 2 or more would disqualify the patient and require discussion with primary team) * Must be able to understand and willing to sign an IRB-approved written informed consent document or be able to provide verbal assent along with written consent provided by a legally authorized representative. Caregiver Eligibility Criteria: * Self-reported as the primary caregiver of a pediatric patient diagnosed with ALL who is also participating in this study. * Must be at least 18 years of age. * Must be able to speak and understand English. * Must be able to perform some level of exercise (e.g., a brisk walk for at least five minutes) as determined by self-report * Must be able to understand willing to sign an Institutional Review Board (IRB)-approved written informed consent document.