To fast or not to fast....breast cancer edition

As a follow up to “Bite on this: Fasting during chemotherapy”, a new study published in the Journal of the American Medical Association further explored the role of fasting during chemotherapy but with a more realistic spin. Unlike previous research that showed that fasting 3-5 days around chemotherapy lessened side effects and increased the efficacy, this study found that fasting for only 13 hours per night was associated with decreased breast cancer recurrence. In reality, fasting for 13 hours per night may translate to eating dinner by 7pm and breakfast at 8am the next morning; definitely not as bad as not eating at all!

This was independent of BMI. The researchers also controlled for other variables like estrogen and progesterone receptor status. Of course, the study has its weaknesses: the data was based on 24-hour diet recalls which may or may not be accurate; perhaps people who fast less than 13 hours per night have more stressful lifestyles, are eating less healthful foods at night or have disturbed sleep patterns. Also, since this was only done in people with breast cancer, the findings may not be able to be extended to other cancer sites.  Ultimately for people fighting a breast cancer diagnosis, fasting for 13 hours per night may be another tool to help flip the odds in their favor.