The amount of fat we eat can easily indicate what season it is. A new study from the UCSF team has shown that meals high in saturated fats can trick the human body. Specifically, they can confuse our internal clock, leading to increased fat storage and weight gain.
According to the researchers, the amount of fat in our diet is linked to how our bodies respond to seasonal changes.
What Did the Scientists Discover?
“The types of food you consume help your determine the season,” neurologist Dan Levin, the lead author of the study, told BBC Science Focus in an interview.
His team found that when we consume more saturated fats, which are found in red meat, butter, cakes, pies, and other buttery pastries, the protein PER2, which regulates circadian rhythms, signals the body that it’s summer, prompting it to store more energy in preparation for the cold winter months.
However, if we eat more —those found in nuts, seeds, fatty fish, and plant oils—PER2 makes the body believe that winter has already arrived, and that we need to burn the energy we consume.
At least, that was the outcome of a non-invasive experiment on mice. The team exposed them to cycles of light and darkness to simulate seasonal changes. When the scientists wanted to mimic spring and autumn, the rodents received 12 hours of light per day; for summer, it was 20 hours, and for winter, just 4 hours of light.
As the nights grew longer in the artificial winter, the mice that were fed a balanced diet exhibited typical winter behavior for nocturnal rodents. They began running on wheels as soon as it got dark.
Meanwhile, the mice that were fed high-fat foods took longer to wake up. They started running significantly later than the artificial sunset. This indicates that their internal clocks were somewhat out of sync with the light cycles.
The researchers then compared the effects of different types of dietary fats. They found that mice consuming a diet high in saturated fats woke up and began running on wheels only many hours after midnight. Thus, their internal clocks became increasingly desynchronized from the light schedule as they consumed more saturated fats during the artificial winter.
Dr. Levin noted that most of the findings from the rodent study are relevant to humans.
“In the wild, seasonal changes in water, light, and temperature completely alter the landscape and force organisms throughout the food chain to adapt. One such adaptation is for plants to produce more unsaturated fats to survive the cold. This compels herbivores and carnivores to consume and store more of these types of fats,” Dr. Levin remarked.
Therefore, our bodies are programmed to seek out more unsaturated fats as the days grow shorter. However, many people lose this natural process of dietary change because they have access to the same foods year-round.
We can indulge in our favorite high-saturated-fat foods regardless of the season, forgetting that excessive consumption in the fall and can desynchronize our biological clocks. The team emphasized that it is generally healthier to eat according to a schedule aligned with our daily circadian rhythms.
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