A study from Yale examines how mindset affects hunger by measuring levels of the “hunger hormone” ghrelin. The study finds that how we perceive food affects our feelings of hunger or satiation.
The Study
Researchers gave participants milkshakes to consume on two separate occasions. In one instance, researchers told participants that they have a high fat and high calorie “indulgent shake”. On another occasion, researchers informed the participants that they are consuming a low fat and low calorie “sensi-shake”. In reality, however, participants were consuming the identical shakes on both occasions.
The Results
In each session, researchers measured levels of ghrelin, or the hunger hormone, by drawing blood. When participants thought that they were consuming the indulgent shake, ghrelin levels declined. Meaning, the participants felt fuller. On the other hand, when participants consumed the sensi-shake, ghrelin levels did not experience a similar drop. Remember that participants consumed the same exact shake.
This shows that when we think we consume indulgent foods, we are more likely to feel full. Conversely, when we think we are consuming “diet” food, we tend to not feel as satiated. And in all likelihood, might tend to eat more of the “diet” food as a result.
Elevated ghrelin levels in the stomach also mean that metabolism slows down.
Does this mean nutrition information, calories, and facts about a particular food don’t really matter? In an NPR interview with one of the authors of the study, Assistant Professor of Psychology and Director of the Mind and Body Lab at Stanford University, Alia Crum says: “I don’t think I would go that far yet”, and more tests need to be done. Note that data from the study is based on 46 participants.
The Lessons
The study points to the importance of how our knowledge of food and labeling can have physiological effects. Generally, it’s a reminder of the power of mind over body.
Labels such a “low fat” can influence how we metabolize food. This comes at a time when consumers are more conscious about ingredients and looking for healthier options. A caution that in our attempt to choose the “diet” option, we might tend to eat more of it.
In the study, the authors point to previous studies on how the mind can affect our physiology. Although these studies are not about hunger, they deserve a mention. Examples include how “identifying housework as a good source of exercise can elicit corresponding physiological benefits without any changes in actual activity,” or how “people like the the taste of coke better when it’s in a brand-name cup”.
Did You Know?
The FDA finalized guidelines for the first nutrition labeling in 1973. The growth of processed food led to the consumer demand for nutritional information as more people ate processed food. The FDA continues to update guidelines, with the latest one in 2016.
