The small study found that night owls who preferred to eat breakfast later tended to have a higher BMI compared with people who went to sleep earlier and ate breakfast earlier.
If you have type 2 diabetes, being a night owl and getting a late start on breakfast may make it harder to manage your blood sugar. Study results released this month suggest these habits are linked to a higher body mass index (BMI).
For the small study, published in the April edition of Diabetic Medicine, researchers recruited 210 non-shift workers with type 2 diabetes in Thailand, and had them self-report whether they are at their best in the morning or evening (a state described as chronotype). Participants also answered questions about meal timing and recalled what they ate over a single day, so researchers could observe their eating habits and calorie intake. Researchers also measured participants’ weight, as well as their BMI, which is a common measure of body fat and a predictor of disease risk. Being overweight or obese can increase insulin resistance, the hallmark of type 2 diabetes, and increase diabetes risk or make stabilizing blood sugar more difficult if you already have the disease.
Why Breakfast Timing May Hold a Key to BMI in People With Type 2 Diabetes
“We were looking at this group in particular to see if the evening preference would be associated with body mass index,” says Sirimon Reutrakul, MD, one of the study’s coauthors and an endocrinologist at University of Illinois College of Medicine in Chicago. “There are some behaviors that are associated with evening types, who generally prefer later bedtime [and] later waking times,” she says, explaining that these individuals’ mealtimes tend to be later, too.
She and her team knew these habits were linked to adverse metabolic effects, she says, citing prior research, published in September 2013 in Diabetes Care, which she participated in, and that, independent of sleep quality, found later chronotypes with type 2 diabetes (who ate dinner later) had poorer glycemic control than early chronotypes with the disease.
Reutrakul says another study she coauthored, which was published in December 2015 in Sleep Medicine Clinics, found similar results, and linked disruption of the body’s circadian rhythm to a higher risk of type 2 diabetes, heart disease, or stroke. Circadian rhythm is the body’s internal 24-hour clock that governs when you’re alert and when you’re sleepy.
Results of the current breakfast study suggest that having a late breakfast in particular — a habit of late chronotypes — is linked to having a higher BMI. Modifying meal timing and fighting your circadian rhythm’s natural inclination might help to stave off obesity in people with type 2 diabetes, the authors concluded.