A new study from Tohoku University Graduate School of Medicine reveals a surprising connection between the month you were conceived and your body fat levels as an adult. Researchers now believe that the season of conception could have lasting effects on your metabolism.
Brown Fat: The Body’s Natural Fat Burner
At the heart of this discovery is brown adipose tissue (BAT)—a special type of fat that actively burns calories to generate heat. According to the study, people conceived between mid-October and mid-April are more likely to develop higher levels of active BAT. As a result, these individuals tend to maintain a lower body mass index (BMI) and have better blood sugar regulation.
Warm-Weather Conception May Increase Fat Risk
In contrast, those conceived during warmer months may have less active brown fat, which can lead to higher levels of visceral fat—a harmful type of fat that wraps around internal organs. This may increase the risk of weight gain and metabolic issues in adulthood.
Cold Temperatures May Trigger Genetic Adaptations
So, what causes these differences? Researchers suggest that cold environmental temperatures during conception may trigger epigenetic changes—modifications in gene activity that don’t alter the DNA itself. These changes can shape how the body stores and uses fat throughout life.
A New Piece in the Obesity Puzzle
While your month of conception isn’t the only factor influencing your weight, this study adds a compelling layer to our understanding of obesity and metabolic health. It highlights how early environmental cues—before birth—can program the body in subtle yet powerful ways.
