“We assessed whether timing of meals is associated with breast and prostate cancer risk taking into account lifestyle and chronotype, a characteristic correlating with preference for morning or evening activity,” Kogevinas and his team wrote in the study.
Each participant was interviewed about their eating patterns (including timing of meals), sleep patterns, chronotype and completed a “Food Frequency Questionnaire.” Researchers also measured participants’ adherence to global cancer prevention recommendations.
According to the study, participants sleeping two or more hours after dinner had a 20 percent lower risk of developing prostate or breast cancer combined compared to subjects sleeping immediately after dinner.
Researchers observed a similar difference when participants ate dinner before 9 p.m. and when they ate after 10 p.m.
Those who were more likely to adhere to cancer prevention recommendations, as well as “morning people” also had lower risk of developing breast or prostate cancer.
"The present study suggests that changes in timing of circadian controlled activities in sleep or diet that are less extreme than those observed in night shift work, are associated with long term health effects increasing the risk of the most prevalent cancers worldwide," study authors concluded.
“The World Cancer Research Fund estimates that about a quarter to a third of the commonest cancers are attributable to excess body weight, physical inactivity and poor diet, making these the most common causes of cancers after smoking,” they added. “If timing is proven to be a significant modifier of these effects then it would be important to also define eating and sleep time as one of the recommendations.”
The self-reported assessment of food consumption was retrospective, which authors noted may have limitations. Another limitation of the study: small variability in meal timing, which may affect precision.