SUO 2018: Impact of Food Intake Timing on Metabolic Health and Cancer Risk in Humans

Phoenix, Arizona ( In the session, "Fasting Interval, Metabolism, and Cancer Risk", Dr. Marinac focused on the clinical impact of food intake timing on metabolic health and cancer risk in humans. The premise is that timed restricted fasting (TRF), which she labels nightly fasting, may be associated with and relevant to multiple obesity-related cancers (seen below), as well as loosely associated with others, such as prostate cancer.

Can mealtimes influence metabolic health and cancer related endpoints in humans?  Below is the distribution of night-time fasting (by hours) of women in the NHANES study: 
Therefore, some patients are already nightly fasting. A longer nightly fasting is associated with better glycemic control and lower CRP levels. 

She then discussed the Women’s Healthy Living and Eating Study, which was a randomized controlled dietary intervention study among 3088 breast cancer survivors. Patients were followed longitudinally, and measurements were repeated at baseline, 1 and 4 years. Clinical endpoints assessed were breast cancer events (7.3 years follow-up) and mortality (cancer-specific and overall). 

  • Nighttime fasting durations were estimated from time-stamped dietary recalls
  • Breast cancer recurrence was significantly lower in patients who had nightly fasting >= 13 hours vs. < 13 hours
  • HR for Breast cancer specific survival (nightly fasting >= 13 hours vs. < 13 hours): HR 1.21, p = 0.19
  • There was no difference In overall mortality either
Lastly, they recently completed a study looking at the feasibility of 12 hour nightly fasting. They prospectively assessed 20 postmenopausal obese women (50% Latina). They then completed the following intervention:

After 1 month, they noticed the following results: 

While not expected (and not explained to the patients as a potential benefit), they noted a 1 kg weight loss in 1 month regardless of race. Mean nightly fast was 13-13.2 hours – from a baseline of 10.6-10.8 hours. There was no difference based on race.

Most importantly:

  • 90% said the fast was easy
  • 90% said that they could fast > 12 hours
  • 70% said they preferred text messaging over telephone counseling
  • 90% found fasting somewhat pleasant
Based on these studies, she concludes that prolonged nightly fasting is feasible without any evidence of harm to the patient. It may also improve cancer prognosis. 

Take-Home Statement: Prolonged nightly fasting may be a strategy to reduce cancer risk and excess morbidity and mortality among cancer survivors. 

Presented by: Catherine Marinac, PhD, Dana-Farber Cancer Institute, Boston 

Written by: Thenappan Chandrasekar, MD Clinical Instructor, Thomas Jefferson University, twitter: @tchandra_uromd at the 19th Annual Meeting of the Society of Urologic Oncology (SUO), November 28-30, 2018 –Phoenix, Arizona