Your weight affects how and when your body burns energy. People with a healthy body weight use more energy during the day, whereas people with obesity burn more energy at night.
A new study by experts at Oregon Health & Science University (OHSU) examined whether obesity affects circadian fluctuations in energy and glucose metabolism in humans. The results have been published in the English-language journal “Obesity”.
Obese and normal weight participants
The team examined a total of 30 participants in a special circadian research laboratory who either had a body mass index (BMI) in the healthy weight range or in the obesity range.
The study followed a strict circadian research protocol. This included a schedule that determined when participants were awake and when they were asleep. After each of the sleep phases, the participants were woken up to eat food and then complete various tests throughout the day.
Energy metabolism analyzed
For example, in one of the tests they were instructed to perform physical exercises while wearing a special mask. This mask was connected to a calorimeter, which measures exhaled carbon dioxide and helps estimate energy consumption, the researchers explain.
In this way, energy metabolism was measured at rest and during the standardized training session. In addition, blood was taken before and after each meal to determine glucose and insulin levels.
Different times of energy consumption
The researchers found that participants with a healthy body weight burned more energy throughout the day, whereas people with obesity expended more energy at night.
Additionally, it was found that obese participants had higher insulin levels during the day. This suggested that the body was working harder to use glucose, according to the team.
“It was surprising to see how dramatically the timing at which our bodies burn energy differs in people with obesity. However, we’re not sure why. Burning less energy during the day could contribute to being obese, or it could be the result of obesity,” says study author Dr. Andrew McHill in a recent press release.
High blood pressure and diabetes due to obesity
Obesity is defined as a body mass index (BMI) of 30 or more and has been shown to increase the risk of health problems and diseases, including high blood pressure and type 2 diabetes, the team explains.
The times at which people sleep, eat and exercise can also impact health by either complementing or counteracting the body’s natural circadian rhythm, the researchers continued.
According to the experts, previous studies have already suggested that incorrect alignment of the circadian rhythm affects energy metabolism and glucose regulation. However, these studies mostly examined people with a healthy weight.
The new study now shows that obesity is associated with altered circadian energy and glucose metabolism, and a better understanding of these relationships could lead to strategies that improve body weight and metabolic health in people with obesity. (as)