Eating later in the day may contribute to weight gain, according to a study presented at ENDO 2019, the Endocrine Society‘s annual meeting in New Orleans. Previous studies have suggested that later timing of eating and sleeping are related to obesity, said lead author Dr Adnin Zaman, of the University of Colorado in Denver. “However, few studies have assessed both meal and sleep timing in adults with obesity, and it is not clear whether eating later in the day is associated with shorter sleep duration or higher body fat,” she said.
The study used three types of technology to record participants’ sleep, physical activity and eating patterns. “It has been challenging to apply sleep and circadian science to medicine due to a lack of methods for measuring daily patterns of human behaviour,” Zaman said. “We used a novel set of methods for simultaneous measurement of daily sleep, physical activity, and meal timing patterns that could be used to identify persons at risk for increased weight gain.”
The week-long study included 31 overweight and obese adults, average age 36 – 90% were were women. They were enrolled in an ongoing weight-loss trial comparing daily caloric restrictions to time-restricted feeding, meaning they could only eat during certain hours of the day.
Participants wore an activPAL electronic device on their thigh. This device measured how much time they spent in physical and sedentary activities. They also wore an Actiwatch, which assesses sleep/wake patterns. Participants were asked to use a phone app called MealLogger to photograph and time stamp all meals and snacks throughout the day.
The researchers found that on average, participants consumed food throughout an 11-hour time-frame during the day and slept for about 7 hours a night. People who ate later in the day slept at a later time, but they slept for about the same amount of time as those who finished eating earlier. Later meal timing was associated with a higher body mass index as well as greater body fat.
“We used a novel set of methods to show that individuals with overweight or obesity may be eating later into the day,” Zaman said. “These findings support our overall study, which will look at whether restricting the eating window to earlier on in the day will lower obesity risk.”
“Given that wearable activity monitors and smartphones are now ubiquitous in our modern society, it may soon be possible to consider the timing of behaviours across 24 hours in how we approach the prevention and treatment of obesity,” Zaman said.
Background: Emerging literature suggests that later timing of energy intake and sleep are related to obesity (1-3). However, few studies have assessed both meal and sleep timing in adults with obesity, and it is not clear whether eating later in the day is associated with shorter sleep duration or higher adiposity. Understanding whether temporal feeding and sleep patterns are associated with body composition will help in the design of novel weight loss and maintenance interventions aimed at altering the timing of lifestyle behaviors.
Methods: Thirty-two overweight and obese adults (90% female sex, age 36.4±6.4 years, and BMI=33.4±5.5 kg/m2) were recruited to participate in an ongoing weight loss trial comparing daily caloric restriction to time-restricted feeding. Participants simultaneously wore an activPAL accelerometer on the thigh and an Actiwatch on the non-dominant wrist for 7 days in a free-living environment to assess waking sedentary behavior and nighttime sleep, respectively. A cell phone application (MealLogger) was used to photograph and timestamp all caloric events during the 7-day period to determine daily feeding duration, which was verified using a continuous glucose monitor. Assessments were performed at baseline and will be repeated at 12 weeks following completion of the weight loss intervention. Correlation analyses were performed on baseline data to determine associations among the duration and timing of daily energy intake and sleep. Results are reported as mean±SD.
Results: On average, participants consumed energy over 11.0±1.9 hours during the day and slept for 7.2±0.7 hours at night. The clock time of the last caloric event averaged 7:54pm ± 93 min. Later meal timing (midpoint of the feeding window) was positively correlated with later sleep timing (midpoint of the sleep window, r = 0.67, P = <0.0001) but did not impact sleep duration. A later feeding midpoint correlated with higher BMI (r = 0.49, P = 0.005) and fat mass (r = 0.55, P = 0.001).
Conclusions: We used a novel set of methods to show that individuals with overweight and obesity may be eating later into the day. In addition, later meal timing was associated with higher BMI and fat mass. Future studies are needed to compare the timing of energy intake and sleep in normal weight versus obese individuals. These findings support ongoing studies by our group investigating whether restricting energy intake to the early part of the day lowers obesity risk.
Adnin Zaman, Corey A Rynders, Sheila Steinke, Emma Tussey, Elizabeth H Kealey, Elizabeth A Thomas