Research suggests that eating breakfast after 9 a.m. can significantly increase the risk of developing type 2 diabetes compared to an earlier breakfast. The study examined the eating patterns of over 100,000 participants, finding that meal timing affects the risk of diabetes, with a late breakfast adversely impacting glucose control and insulin levels.
A study that followed more than 100,000 participants for seven years suggests eating breakfast after 9 a.m. increases type 2 diabetes risk by 59%, highlighting the importance of meal timing in disease prevention.
Eating breakfast after 9 a.m. increases the risk of developing type 2 diabetes by 59% compared to people who eat breakfast before 8 a.m. This is the main conclusion of a study in which ISGlobal, an institution supported by “la Caixa” Foundation, took part and which followed more than 100,000 participants in a French cohort. The results show that we can reduce the risk of diabetes not only by changing what we eat, but also when we eat it.
The Impact of Meal Timing
Type 2 diabetes is associated with modifiable risk factors, such as an unhealthy diet, physical inactivity, and smoking. However, the time at which we eat may also be an important factor. “We understand that meal timing plays a crucial role in regulating circadian rhythms and glucose and lipid control, but the relationship between meal timing, fasting, and type 2 diabetes has been underexplored,” says Anna Palomar-Cros, a researcher at ISGlobal and the study’s first author.
The study involved a collaboration between ISGlobal and INSERM in France. The researchers investigated the association between meal frequency, timing, and the incidence of type 2 diabetes among 103,312 adults (79% women) in the French NutriNet-Santé cohort. Participants provided online dietary records for three non-consecutive days, including the timing of their meals. The researchers analyzed the data from the first two years of follow-up and monitored the participants’ health for an average of seven years.
Breakfast, Dinner, and Diabetes Incidence
During the study, there were 963 new cases of type 2 diabetes. The group of people who regularly ate breakfast after 9 a.m. had a significantly higher risk of developing the disease compared to those who ate breakfast before 8 a.m. Palomar-Cros explains, “Skipping breakfast negatively affects glucose and lipid control, as well as insulin levels, which biologically contributes to the increased risk of type 2 diabetes. Two meta-analyses have also supported the association between skipping breakfast and diabetes risk.”
The research team also found that eating a late dinner (after 10 p.m.) appeared to increase the risk of type 2 diabetes, while eating more frequently (about five times a day) was associated with a lower incidence of the disease. Interestingly, prolonged fasting was only beneficial when paired with an early breakfast (before 8 a.m.) and an early dinner.
Conclusions and Implications for Chrononutrition
“Our results suggest that having breakfast before 8 a.m. and avoiding late dinners (after 7 p.m.) may help reduce the incidence of type 2 diabetes,” concludes Manolis Kogevinas, a researcher at ISGlobal and co-author of the study. The ISGlobal team had previously provided evidence of the link between early dinners and a lower risk of breast or prostate cancer. These findings further support the use of chrononutrition, which focuses on the association between diet, circadian rhythms, and health, for preventing type 2 diabetes and other chronic diseases.
Reference: “Associations of meal timing, number of eating occasions, and nighttime fasting duration with the incidence of type 2 diabetes in the NutriNet-Santé cohort” by Anna Palomar-Cros, Bernard Srour, Valentina A Andreeva, Léopold K Fezeu, Alice Bellicha, Emmanuelle Kesse-Guyot, Serge Hercberg, Dora Romaguera, Manolis Kogevinas, and Mathilde Touvier, 16 June 2023, International Journal of Epidemiology.
DOI: 10.1093/ije/dyad081
Funding: PRE2019-089038/Ministry of Economy in Spain
