Follicular lymphoma (FL) is a prevalent form of non-Hodgkin lymphoma characterized by the gradual expansion of abnormal B cells, known as lymphoma cells, within follicles, or nodules, that can accumulate in the lymphatic system and various tissues throughout the body. FL development is heterogenous and evaluated based on histological grade (1, 2, 3a, 3b) and stage (I, II, III, IV, bulky), determined through imaging and clinical presentation. Treatment strategies range from observation or localized radiation for non-aggressive, slow-growing, low-grade FL to more intensive approaches such as chemotherapy, immunotherapy, radiation, or combination therapy for aggressive, high-grade, and/or advanced stage FL. Improvements in immunotherapy have increased five-year survival rates, but patients may still need to undergo multiple treatments to achieve FL remission. Additionally, relapses commonly occur within 1 to 2 years after the initial remission [1]. Fasting is emerging as a promising tool in cancer therapy as evidenced by research suggesting that various periods of controlled nutrient deprivation may enhance the effectiveness of established cancer treatments, mitigate treatment-related side effects, and impede tumor growth [2–4]. Indeed, a growing number of cancer patients are opting to manage the disease with fasting and other complementary and alternative therapies while maintaining diagnostic care with an oncologist that she had maintained yearly follow-up oncology appointments that included serological and computed tomography (CT)/positron-emission tomography
(PET) examinations, which confirmed her continued remission.

On arrival, the patient had no significant health complaints, was not taking any medications, and had unremarkable clinical and serological exams. She weighed 72.4  kg with a body mass index (BMI) of 27.3  kg/m2 and systolic/diastolic blood pressure of 106/72  mmHg (Table  1). She completed 18  days of fasting, during which she experienced mild nausea and dry mouth, and 10 days of refeeding that was well tolerated. On the 12th day of fasting, standard serology indicated that she
had developed mild hypokalemia with a serum potassium level of 2.9  mmol/L. Other electrolytes tested, including sodium, remained within normal limits, and her neurologic and cardiologic clinical evaluations were unremarkable. She consumed 350 mL of low-calorie vegetable broth four times per day for the next six days until refeeding began. By the end of refeeding, she weighed 67.3 kg with a BMI of 25.4 kg/m2 and systolic/ diastolic blood pressure of 102/69 mmHg (Table 1). On discharge, the patient was in good health. Her yearly oncological evaluation was completed ten months later and revealed serology within normal limits and a MIP PET scan with no evidence of malignancy in the chest, abdomen, and pelvis (Fig. 1).