ISLAMABAD, MAY 23 (ONLINE): Researchers say eating even when you\u2019re full may be associated with sense of smell and behavior motivation.They report that food smells become less attractive when someone is full.
\nIf brain connection doesn\u2019t function properly, researchers say a person\u2019s body mass may be higher.
\nA group of scientists may have discovered one reason why it\u2019s easier for some people to stop eating when they\u2019re full and more difficult for others.<\/p>\n
They say this may be caused by our sense of smell and neural reward systems versus negative feelings such as pain as well as the brain connection between the areas controlling those feelings.<\/p>\n
The study from researchers at Northwestern Medicine in Illinois states their theory is based on a newly discovered structural connection between two brain regions that appear involved in regulating feeding behavior.<\/p>\n
The researchers used neurological imaging from a large multi-center National Institutes of Health (NIH) projectTrusted Source designed to map the human brain called the Human Connectome Project.<\/p>\n
The regions of the brain the study examined have been associated with sense of smell and behavior motivation.<\/p>\n
The researchers found that weaker connections between these two sensory regions, the higher a person\u2019s body mass index (BMI), the researchers said.<\/p>\n
Connection between brain regions affects how much we eat
\nThe areas under study connects the olfactory tubercle \u2013 part of the brain\u2019s reward system associated with smell \u2013 and a midbrain region called the periaqueductal gray (PAG), which is involved in motivated behavior responding to negative feelings such as threat, pain and, potentially, eating suppression.<\/p>\n
Research has shown the smell of food is appealing when a person is hungry, but the odor becomes less attractive when that person eats the food until they\u2019re full.<\/p>\n
The most recent study, published in the Journal of Neuroscience, reported that odors are important to guiding motivated behaviors such as eating and\u2014 in turn \u2014 olfactory perception is modulated by how hungry we are.<\/p>\n
However, researchers haven\u2019t fully evaluated the neural underpinnings of how the sense of smell contributes to how much we eat.<\/p>\n
\u201cThe desire to eat is related to how appealing the smell of food is \u2014 food smells better when you are hungry than when you are full,\u201d said Guangyu Zhou, a corresponding study author and a research assistant professor of neurology at Northwestern University Feinberg School of Medicine, in a statement. \u201cBut if the brain circuits that help guide this behavior are disrupted, these signals may get confused, leading to food being rewarding even when you are full.\u201d<\/p>\n
The sensation of reward that comes with food could possibly, in turn, increase a person\u2019s body mass index (BMI).<\/p>\n
\u201cAnd that is what we found,\u201d Zhou said. \u201cWhen the structural connection between these two brain regions is weaker, a person\u2019s BMI is higher, on average.\u201d<\/p>\n
The authors hypothesized that healthy brain networks connecting reward areas with behavior areas can regulate eating behavior by sending messages indicating eating doesn\u2019t feel good anymore once that person is full.<\/p>\n
A weak brain connection could mean excess eating
\nThe researchers said that people with disrupted or weak connection circuits may not receive the stop signals and keep eating, even when they\u2019re not hungry.<\/p>\n
\u201cUnderstanding how these basic processes work in the brain is an important prerequisite to future work that can lead to treatments for overeating,\u201d said Christina Zelano, a senior study author and an associate professor of neurology at Feinberg, in a statement.<\/p>\n
Zhou said they found correlations to BMI in the circuit between the olfactory tubercle and the midbrain region called the periaqueductal gray.<\/p>\n
For the first time in humans, Zhou mapped the circuit\u2019s strength across the olfactory tubercle, then replicated the findings in a smaller MRI brain dataset the team collected in their Northwestern lab.<\/p>\n
\u201cFuture studies will be needed to uncover the exact mechanisms in the brain that regulate eating behavior,\u201d Zelano said.<\/p>\n
Emily Spurlock, a registered dietitian with the Institute for Digestive Wellbeing in New York, specializes in gut health and weight management. She also works with people who have binge eating disorder.<\/p>\n
Spurlock, who was not involved in the research, told Medical News Today that the study offers scientific evidence that some people eat for reasons other than hunger.<\/p>\n
\u201cI\u2019ve seen this in my practice for many years. In fact, I think we all do it to some extent,\u201d Spurlock said. \u201cThink about Thanksgiving or any time you\u2019ve \u2018found room\u2019 in your stomach for ice cream. Some people are better at listening to their body\u2019s fullness signals than others. For some people, the smell and sight of a favorite dessert is more powerful than being stuffed.\u201d<\/p>\n
Reacting to overeating
\nSpurlock said when a person overeats to the point of being uncomfortable the first time, they likely acknowledge it. However, the more it happens, they likely get \u201cdesensitized and overeating is no longer as uncomfortable as it was that initial time.\u201d<\/p>\n
\u201cOver time, that brain connection gets \u2018broken\u2019 because it\u2019s being ignored or overwritten by frequent overeating,\u201d Spurlock said. \u201cMaybe some people start off with a stronger brain connection and overeating never becomes a problem. My question from the study is if people can rebuild that connection or build a stronger connection so they are more in tune with the uncomfortable feeling of overeating?\u201d<\/p>\n
Kate Ringwood is the owner of Serendipity Counseling Services and a therapist specializing in eating disorders.<\/p>\n
Ringwood, who wasn\u2019t involved in the study, told Medical News Today that the idea of a physical connection between two brain regions that appear involved in regulating feeding behavior isn\u2019t new. But she said she has a different perspective.<\/p>\n
\u201cThrough my experience, those who are dieting \u2013 which often includes folks going on weight loss medications \u2013 are restricting foods,\u201d Ringwold said. \u201cWhen food is restricted, it puts the brain into \u2018survival mode,\u2019 leading your brain to think it needs to eat all the food, in fear that it will not get this food again.\u201d<\/p>\n
\u201cThis happens whether it is mental restricting \u2013 for example, not allowing yourself to eat cookies and then later binging when cookies are put in front of you \u2013 or physical restriction (by) simply not eating enough calories for your body to properly function,\u201d Ringwold said. \u201cI have seen this over and over again in the work I do with clients, leading folks to feel extremely uncomfortable and sometimes ill feeling.\u201d<\/p>\n
Ringwold said restricting food leads to a disconnect from one\/s body.<\/p>\n
\u201cIf you are not eating when your body is trying to signal you that it needs food, you teach your body that the signal cannot be trusted,\u201d she explained. \u201cThis leads to distrust and confusion when it comes to hunger and fullness cues.\u201d<\/p>\n
Ringwold added that when someone restricts eating, their body starts shutting down hunger and fullness cues.<\/p>\n
\u201cThe way I often phrase this to clients is, when you had to hunt for food, if your body showed signs of major hunger such as shaking, brain fog, stomach pain, you would not be able to get food,\u201d Ringwold said. \u201cThe body is amazing in that it shuts down signals that feel \u2018less important.\u2019 When we ignore our hunger and fullness cues, it shuts them down.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"
ISLAMABAD, MAY 23 (ONLINE): Researchers say eating even when you\u2019re full may be associated with sense of smell and behavior motivation.They report that food smells become less attractive when someone is full. If brain connection doesn\u2019t function properly, researchers say a person\u2019s body mass may […]<\/p>\n
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