Our bodies are designed with a simple hunger mechanism: hunger pangs trigger the desire to eat, and when our stomach feels full, it's an indication that we've had enough to eat. Pretty simple, right?
Hunger Equals Eat. Full Equals Stop Eating.
Unfortunately, this isn't always the case. According to a new , these associations (hunger equals eat; full equals stop eating) might be learned in reverse. The result: feeling full can cause you to eat more rather than less.
The study took 32 rats and put them through a daily 30-minute conditioning session over the course of 12 days. After being fed, the rats were put in a box that had a lever that fed them tasty treats when pressed. For the following four days, the rats (who hadn't been fed and were hungry) were put in the same box with the same lever, but the lever produced no treats when pressed.
When the rats were placed in the box again, they were far more prone to pressing the treat-producing lever when they were full rather than hungry. The previous 16 days had conditioned them to believe that the feelings of fullness were a signal that they wanted something tasty. It didn't matter that they had eaten their fill—they wanted the treats.
But that's not all. According to the research, "This relapse pattern emerged even when food was removed from the cage before both the learning and unlearning sessions, indicating that the rats’ internal physical states, and not the presence or absence of food, cued their learned behavior."
You may think, "I'm not a rat; I'm not going to react that way." Well, the truth is that learned behaviors exist among all animals, including those of us that walk upright on two legs. Our body may drive our food-seeking behavior based on actual physiological needs (genuine hunger), but internal cues and conditioned behavior can also affect our food-related behavior.
The lead researchers explained, “A wide variety of stimuli can come to guide and promote specific behaviors through learning. For example, the sights, sounds, and the smell of your favorite restaurant might signal the availability of your favorite food, causing your mouth to water and ultimately guiding you to eat."
These stimuli don't trigger your hunger pangs—hunger is a physiological response. Instead, it will trigger your cravings for something delicious, and that's the type of response that leads to excessive calorie consumption, weight gain, and ultimately obesity.
1. Scott T. Schepers, Mark E. Bouton. "." Psychological Science, 2017; 095679761771908 DOI: 10.1177/0956797617719084.