I admit to hedonic, glutonous eating . Peggy, on the other hand, is a homeostatic eater and that’s why she weighs within 8 pounds of her teen-age years and I don’t. Put a plate, a bag, a carton of anything that I find tasty and it’s polished off.
- Homeostatic feeding occurs when an “animal” eats until it has satiated its hunger and restored its energy levels.
- Hedonic feeding describes an “animal’s” drive to eat more than it needs if the food source is particularly nutrient-dense and delicious.
Humans are not the only mammal with a drive to overeat high-calorie foods.
In evolutionary terms, when an animal finds a food source high in nutrients, it makes sense to eat as much as possible; in the wild, starvation is an ever-present danger. ( I’m alert to the ever-present danger of starvation )
My doctors told me to stop eating sugar and gluten (that’s another story) It’s REALLY challenging to find foods that are not packed with sugar and/or fat . . . that I “crave”. Energy-dense foods are every where I look and I (along with other mammals) have evolved to find these types of food delicious — and food companies know it.
Researchers find a brain circuit in mice that plays a role in overindulging in high-calorie foods.
As new study co-author Prof. Thomas Kash, Ph.D., points out, “There’s just so much calorically dense food available all the time now, and we haven’t yet lost this wiring that influences us to eat as much food as possible.”
Recently, researchers from the University of North Carolina Health Care in Chapel Hill looked at this phenomenon in rodents’ brains. Researchers investigated the mechanisms involved in homeostatic feeding, but did not find successful interventions. More recently scientists have looked to hedonic feeding for answers.
Nociceptin and overeating
Research has demonstrated that nociceptin receptors (nociceptin is a peptide with 17 amino acids) make little difference to homeostatic feeding, but that they may influence hedonic feeding.
Prof. Kash and team engineered mice to produce fluorescent nociceptin. This made it easier to see the cells involved in nociceptin circuits.
Many circuits in the brain utilize nociceptin, but the researchers identified one particular circuit in the amygdala that lit up when the mice binged on energy-dense foods. This circuit has projections to other parts of the brain that help regulate feeding. It originates in the central nucleus of the amygdala, a part of the brain that plays a vital role in an animal’s response to emotional stimuli.
“Scientists have studied the amygdala for a long time, and they’ve linked it to pain and anxiety and fear, but our findings here highlight that it does other things too, like regulate pathological eating.“
The authors believe that “this is the first study to ascribe specific hedonic feeding actions to a subpopulation of [central amygdala] neurons.”
Removing the overeating circuit
In follow-up experiments, the scientists deleted around half of the neurons that produce nociceptin in the circuit. They found that this reduced levels of binge eating.
They gave the mice access to standard chow and high-calorie food, alternatively. With these neurons silenced, the mice significantly reduced their intake of high-calorie food and resisted diet-induced obesity. Their consumption of standard chow remained consistent.
“Our study is one of the first to describe how the brain’s emotional center contributes to eating for pleasure,” explains first study author J. Andrew Hardaway, Ph.D.
“It adds support to the idea that everything mammals eat is being dynamically categorized along a spectrum of good/tasty to bad/disgusting, and this may be physically represented in subsets of neurons in the amygdala.”
The next step for me is to instruct my amygdala to love vegetables. (jw)