Meal Times and Weight Gain

Evidence of the association between eating later in the day and weight gain, gained another boost from researchers at the University of Colorado in the United States who used in-depth personal monitoring to gain fresh insight on the theory.

As obesity rates around the world continue to grow, finding ways to curb this is becoming critical. Sticking to a restrictive, calorie-controlled diet is challenging, but eating at a different time of the day might be more easy to achieve. If changing eating timings has even a small effect on obesity, it is worth exploring in more detail.

Earlier studies have identified a pattern between eating later and increased weight gain. However, it is not clear whether individuals who eat later in the day might, consequently, have less sleep overall. This factor is important because experts also believe that sleeping less may play a part in obesity.

Researchers behind the new study point out that 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.

The scientists recruited 31 adults with an average age of 36 years who were overweight or had obesity. To capture as much relevant information as possible, the scientists assessed the participants’ sleep, levels of activity, and diet.

Each participant wore an Actiwatch that monitored their sleep-wake cycles. They also wore an activPAL electronic device on their thigh, which measured how much time they spent both doing physical activity and being sedentary

The participants kept track of what they ate using a phone app called MealLogger. Using the app, they photographed each meal and snack that they consumed, which provided the time of day that they ate it. The researchers used a continuous glucose monitor to verify dietary intake.

The analysis showed that, on average, the participants ate their food during an 11-hour window and had 7 hours of sleep each night.

As expected, those who ate later in the day had a higher BMI and greater levels of body fat. Importantly, the researchers also showed that those who ate later in the day still had an average of 7 hours of sleep, implying that a lack of sleep is not the primary driver of these effects.

With wearable activity monitors and smartphones becoming ubiquitous in modern society, it may soon be possible to consider the timing of behaviors across 24 hours and use this to prevent and treat obesity, said the researchers.

As the latest findings align with those of earlier investigations, the timing of meals may become an increasingly important focus in the study and treatment of obesity.