Does Eating Late at Night Affect Cancer Risk?

People who are looking to actively decrease their cancer risk often make healthy changes to their diet—for example, by limiting the consumption of red meat, alcohol, and refined carbohydrates, and increasing the consumption of plant-based foods like fresh fruits and vegetables. However, new evidence points to the fact that the time of day that people choose to eat can play a role in cancer risk as well.

A study by researchers at the Barcelona Institute for Global Health suggests that people who stop eating at least two hours before they go to sleep may lower their risk of certain cancers. Catherine Marinac, PhD, of the Division of Population Sciences at Dana-Farber Cancer Institute, answered some questions about these findings, and what they mean for people looking to reduce their cancer risk.

Is there a time that people should try to stop eating by to reduce their cancer risk?

Evidence suggests that the body responds differently to calories consumed at different times of the day. In particular, we don’t seem to be as good at processing food at night as we are during the daytime hours. We think this has to do with our circadian rhythm, which is roughly the 24-hour internal clock that controls a wide range of things in the body, including metabolism. The exact time that people should try to stop eating for cancer prevention and overall health is something that researchers are still working to better understand.

A clock

Does what you eat at night make a difference?

Much of the research in this area seem to suggest that the health benefits of limiting or reducing nighttime eating is independent of how much people eat throughout the day. However, it may be too soon to tell if the types of foods people eat at night make a difference.

Is the reduction in cancer risk related to whether the people who avoided eating late were a healthier weight?

Many of the studies that suggest a benefit to limiting nighttime eating have attempted to control for the weight or body mass index (an index of weight in relation to height) of participants. Therefore, the beneficial effects do not seem to be dependent on whether someone is at a healthy weight.

Are the findings from these studies reason enough for people to alter their nightly routines?

Altering the time of meals is a relatively simple change that many people can understand and adopt if they so choose. Altering meal timing doesn’t require people to change what they eat or how they cook, which can make it a relatively simple dietary change for some people. If future trials confirm that altering meal timing meaningfully improves health and reduces disease risk, then altering the timing of meals could be a simple disease prevention strategy that does not require a dramatic change in lifestyle.

However, while the evidence to date points to a benefit from reducing or eliminating nighttime eating, it is too soon to recommend altering meal times for cancer prevention. Further studies are needed before this change becomes a widespread recommendation for people looking to reduce their cancer risk.

Learn more about nutrition from Dana-Farber Cancer Institute.