Is it recommended to fast before chemotherapy? 

Fasting before chemotherapy is recommended as it may help reduce side effects and improve quality of life during treatment. Research indicates that short-term fasting for 48 to 72 hours before and 24 hours after each chemotherapy cycle can decrease side effects such as nausea, fatigue, diarrhea, and immunosuppression, as shown in animal studies.

In a randomized controlled trial involving breast cancer patients, fasting for 60 to 72 hours around chemotherapy cycles significantly improved health-related quality of life and prevented fatigue compared to a plant-based and low-sugar diet group.

The benefits of fasting appear to be more pronounced with longer durations of at least 48 hours, while fasting for 24 hours may not provide significant advantages. Generally, fasting is well-tolerated in patients not at risk of malnutrition, with no adverse effects reported in studies.