Weight Management in Obese Cancer Patients During Curative Active Treatment

Inclusion Criteria: * Adult (age 18+) with pathologically confirmed malignant solid tumors, stage II-IV, elected for oncological treatment (chemo, radio, or both) with curative intend. * Expected oncological treatment time ≥ 3 months. * BMI ≥ 30 kg/m² * Resident in the Barcelona area up to the completion of cancer treatment. * ECOG Perfomance Status (PS) 0-1 * Availability of internet access. Exclusion Criteria: * Patients with melanoma and brain tumours. * Surgery as the only treatment. * Tumour localizations with high risk of malnutrition (such as head and neck, upper gastrointestinal tract, or pancreatic cancer): * Pregnancy or breastfeeding * Another active malignancy * Current health or medical condition that affects weight status, e.g., untreated hyper- or hypothyroidism,etc * Pre-existing medical condition that precludes adherence to unsupervised exercise, e.g., severe orthopedic conditions, scheduled for a hip or knee replacement, bone metastases, paralysis, dementia, untreated stage 3 hypertension, or unstable angina, heart attack, congestive heart failure or conditions that dictated hospitalization or oxygen within 6-months. * Unable to read or understand Spanish or Catalan * Enrolled in a weight loss program * Active suicidal ideation, anorexia, bulimia, binge eating disorder, current substance abuse or dependence (besides nicotine dependence) * Use of pacemaker or another electrical implanted device * History of bariatric (or LapBand) surgery, or considering or currently on a wait-list for bariatric or LapBand surgery * Patients with any concurrent medical or psychological condition that, in the investigator's opinion, would jeopardize the safety of the patient or compliance with the protocol.