The Nature and Nurture of Liking Food

At The Obesity Society’s annual scientific meeting, Jane Wardle, PhD gave a presentation about eating behavior: Food Responsiveness, Food Liking, and Satiety Responsiveness: Associations with Energy Intake and Weight Gain among Children. One on hand, our genes have not changed in the last several decades, but obesity rates have increased tremendously. This points to environment as a likely primary factor in obesity. On the other hand, Stunkard et al showed that adopted kids have a much stronger relationship to the weight of their biological parents (even if they never lived with them) vs their adoptive parents (who raised them). If anything is clear about obesity and weight, it’s that there is no easy answer or explanation. But researchers agree that the combination of environment and genes is very important in terms of understanding obesity.

Dr Wardle is studying the heritability of traits relating to appetite, such as feeling full. She is conducting studies with babies as young as 3 months old, where she’s found that feeling full, enjoyment of food, and slowness in feeding all seem to be heritable (meaning they’re capable of being inherited), and start early in life. Speaking about similar heritability seen in other species, she cited several animal observations including a study that showed even in spiders, the baby spiders’ meal-size preference is related to the mother spider’s meal-size preference.

Adding to the idea of appetite factors being inherited, another study of kids who had been adopted within a few days of birth showed that the kids have a much stronger food preference correlation with their biological parents, instead of with their adoptive parents. Given strong evidence that appetite is partially genetic, Dr. Wardle is working to answer the question of whether we can we modify appetite or food preferences.

In 2009, Ford et al showed significant ability to learn to eat more slowly, giving hope that appetite characteristics can be changed. Dr. Wardle also believes impulse control may be modifiable. She talked about an experiment where some kids were given lego blocks to make a flower design. Other kids were given gummy bear candies to make the same flower design. After the test, all the kids were offered a different type of candy to eat. The kids that had been resisting eating candy because they were making flower out of it, ate notably less candy when it was presented after, as compared to those that were not practicing impuse control because they were making a flower out of lego. While still very early in the phases of understanding how we can use this learning to help prevent or treat obesity, the findings are promising.