The connection between seasons and our dietary habits may be more intricate than we realise. Recent research from the University of Copenhagen reveals that, for mice at least, winter eating habits could be more favourable for metabolic health than summer habits. The study examines how exposure to different seasonal lighting conditions affects metabolism, body weight, fat mass, and liver fat content.
Lewin Small, the researcher behind the study, noted that variations in light hours between summer and winter can significantly influence energy metabolism, even in non-seasonal animals. Mice exposed to "winter light" hours exhibited lower body weight gain and adiposity, along with more rhythmic eating patterns over 24 hours. These changes ultimately contributed to improved metabolic health.
This groundbreaking study is the first to investigate the impact of light hours on metabolism in non-seasonal animals like mice. While humans don't exhibit seasonal breeding habits, the research highlights the potential influence of light on metabolism.
The motivation for this study stemmed from the vast differences in daylight hours worldwide. Most previous research assumed equal day and night lengths throughout the year, overlooking the real-world variations. Inspired by the dramatic shifts in light between Australian and Danish climates, Lewin Small set out to explore how these seasonal differences affect circadian rhythms and metabolism.
The findings offer essential insights into how light and seasons shape eating patterns. While the study's subjects were mice, it serves as a proof of principle: differences in light hours do impact energy metabolism. Further research in humans may reveal how adjusting exposure to artificial or natural light throughout the year could enhance metabolic health.
Juleen Zierath, a Novo Nordisk Centre for Basic Metabolism Research professor, underlines the importance of this new knowledge. Understanding how light and seasonal variations affect eating patterns can explain why some individuals gain weight more easily or experience weight fluctuations at specific times of the year. This research emphasises the intricate relationship between seasons, light exposure, and eating habits. While conducted with mice, the study lays the groundwork for potential future studies in humans, providing a promising avenue to improve metabolic health by adjusting light exposure in line with seasonal variations.
Want to read more: Read the study ‘Seasonal light hours modulate peripheral clocks and energy metabolism in mice’ in Cell Metabolism.
