You might think you’re healthier in the summer because of the sun and long days. But a study from the University of Copenhagen found that, for mice, eating habits in winter might be better for their health than in summer. They looked at how mice’s metabolism and weight were affected by different types of light – winter and summer light.
Lewin Small, who researched while a postdoc at Novo Nordisk Foundation Center for Basic Metabolic Research at the University of Copenhagen, said, “We found that even in non-seasonal animals, differences in light hours between summer and winter do cause differences in energy metabolism. In this case, body weight, fat mass, and liver fat content,”
“We found this mostly in mice exposed to winter light hours. These mice had less body weight gain and adiposity. They have more rhythmicity in the way they eat over 24 hours. And this then led to benefits in metabolic health.” He added.
This study is groundbreaking as it’s the first to explore how the amount of daylight affects metabolism in mice. Unlike humans and other seasonal animals that only breed at certain times of the year, mice are not limited to specific breeding seasons. Seasonal animals often gain weight before generating to store energy, but this doesn’t apply to mice.
Light hours impact metabolism and this study was inspired by the noticeable changes in daylight duration in different parts of the world.
The researchers typically look into how the time of day affects things like exercise, obesity, and diabetes. However, most studies assume equal daylight and darkness throughout the year.
That’s why they wanted to see how the variation in light between summer and winter affects our metabolism. In most places worldwide, there’s at least a two-hour difference in light between these seasons.
One of the researchers, Lewin Small, shared that coming from Australia to Denmark, he noticed a significant contrast in light between summer and winter, which made him curious about how this might impact our body’s internal clock and metabolism.
So, they decided to subject laboratory mice to varying light durations that mimic different seasons and then examined their metabolic health and daily rhythms.
It’s important to note that since this study involved mice as the test subjects, they can’t automatically apply the findings to humans.
Juleen Zierath, Professor at the Novo Nordisk Center for Basic Metabolism Research (CBMR) and senior author of the study, said, “This is a proof of principle. Do differences in light hours affect energy metabolism? Yes, it does. Further studies in humans may find that altering our exposure to artificial light at night or natural light exposure over the year could be used to improve our metabolic health.”
Lewin Small also mentions that this new information helps us grasp how our eating habits are influenced by daylight and the seasons. It might explain why some people gain more weight at certain times of the year.
He believes that the variations in light between summer and winter could impact when we feel hungry and our hunger patterns throughout the day.
The link between seasons and eating habits is complex and influenced by various factors, including food availability, environmental conditions, and psychological factors. Recognizing these connections can lead to improved dietary choices and more effective strategies for managing weight and overall health throughout the year. Further research in this field can provide valuable insights into the seasonal dynamics of eating behavior.
Journal reference:
- Lewin Small, Leonidas S. Lundell et al., Seasonal light hours modulate peripheral clocks and energy metabolism in mice. Cell Metabolism. DOI: 10.1016/j.cmet.2023.08.005.