Study finds key to why obese people lose pleasure in eating rich foods
ST. PAUL, Minn., March 26 (UPI) -- While it seems like a contradiction, many obese people do not enjoy eating rich, calorie-laden foods.
A study published Wednesday indicates that low levels of a key brain chemical among overweight patients with high-fat diets is responsible for a loss of pleasure from food.
Researchers from the University of California-Berkeley say they may have found why people with obesity have been shown to take less pleasure in eating fatty foods than those of normal weight. The culprit, they say, is a deficit of the neuropeptide neurotensin which is linked to the pleasure activator dopamine.
Neuropeptides act as a signaling molecule in the nervous system, and can affect appetite. These molecules are made up of short chains of amino acids, like other peptides, and they play a crucial role in communication between neurons and other cells.
The findings are significant because diminishing pleasure response from eating high-fat foods can lead obese patients to continue or even increase their unhealthy eating patterns "out of habit or boredom, rather than genuine enjoyment," according to the study, which was published in the journal Nature.
As counterintuitive as it may initially sound, the authors say that restoring the pleasure in eating high-fat foods via the replenishment of neurotensin actually could help reduce the progression of obesity and provide a valuable new tool in fight against the global obesity epidemic.
The need for new strategies is a stark one. More than half of adults and one-third of children and teens worldwide will be overweight or obese by 2050, according to a comprehensive study released earlier this year.
Overweight and obesity rates in adults, children and teens more than doubled over the past three decades, afflicting 2.1 billion adults and 493 million young people with excess weight.
A link between neurotensin, or NT, and eating disorders has been established in previous studies, which found that changes in NT levels are associated with obesity or eating disorders, leading doctors to believe that disrupted NT signaling may contribute to body weight disturbance.
Specifically, research has centered around the NT receptors located in a specific brain region that connect to the dopamine "reward" and "pleasure" network.
However, a key question remained: Does a high-fat diet somehow influence the release of NT in the brain? The new study, led by Stephan Lammel, an associate professor of neurobiology at UC Berkeley's Department of Neuroscience, presents evidence that the answer to this question is yes, leading to hopes that by "upregulating" NT -- perhaps through dietary changes or genetic manipulation -- the pleasure of eating can be restored.
Lammel said the study, which was supported the National Institutes of Health, the McKnight Foundation, the One Mind Foundation and others, has "uncovered a concrete mechanism that may link chronic high-fat diet exposure to a loss of pleasure in eating -- a phenomenon that's been observed for years but lacked a clear explanation."
Specifically, the researchers found that NT becomes significantly reduced in a key brain circuit in obese mice. This reduction essentially blunts the motivational value of enjoyable foods like sugar and fat.
"What's especially compelling is that restoring neurotensin levels -- either by switching back to a regular diet or through targeted genetic approaches -- can bring back that sense of reward," Lammel told UPI in a statement. "This not only increased feeding motivation in specific contexts, but also normalized weight gain, improved mobility and reduced anxiety."
Clinically, "that's really important," he added, saying it suggests that part of the challenge in obesity may not just be overeating due to pleasure, but also continuing to eat without pleasure -- out of habit or diminished reward.
"If we can find ways to restore or rebalance neurotensin signaling in the brain selectively, we may be able to help people regain healthier eating behaviors without broadly suppressing appetite or affecting other systems," he said.
The idea that making eating more pleasurable for obese patients as a way to help them manage their weight may seem paradoxical at first, Lammel admitted.
"After all, we often assume that the more we enjoy food, the more likely we are to overeat," he said. "But our study shows that the reality is more nuanced. What we found is that in mice exposed to a chronic high-fat diet, the brain's reward response -- particularly in circuits involving dopamine and neurotensin -- becomes blunted," but even so, they kept on eating the unhealthy food.
This uncoupling of reward from consumption is important "because it suggests that overeating in obesity isn't always driven by pleasure -- it can become automatic or habitual, which makes it harder to regulate."
So, the paradox is that bringing back the "right" kind of pleasure -- this is, pleasure that's appropriately tied to the reward value of food -- may actually help break the cycle of mindless or habitual overeating, the study team found.
"It's not about encouraging indulgence, but about restoring balance," Lammel said. "If food becomes pleasurable again in a meaningful and regulated way, the body may naturally recalibrate toward healthier patterns of intake."
Another prominent researcher of the connection between NT, dopamine and obesity said the UC Berkeley study represents a significant advancement in the understanding of the role brain chemistry plays in determining our eating habits.
Gina Leinninger, a professor of physiology and leader of the Leinninger Laboratory at Michigan State University's Neuroscience Program, is an expert on how neurons in the brain's hypothalamus regulate energy balance, and how disruption of these neurons contributes to the development of obesity and metabolic disease.
Leinninger, who was not connected to the study, told UPI the work sheds a new light on what had been known previously.
"Neurotensin has long been connected to modulating feeding, but how and where has remained a mystery," she said. "This work makes important strides in connecting neurotensin to the dopamine system that shape show much we want to eat, and therefore how much we do it."

Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles


UPI
2 hours ago
- UPI
Childhood trauma linked to higher risk of endometriosis in adult women
1 of 2 | Endometriosis affects one in 10 women in the United States and can cause chronic and frequently severe pelvic pain. A new study has found that women who experienced childhood traumas are at heightened risk to develop the condition as adults. Photo by cottonbro studio/ Pexels ST. PAUL, Minn., June 11 (UPI) -- A suspected link between childhood trauma and the risk of developing endometriosis in later life was strengthened Wednesday with the publication of study that showed a greater chance of the condition among women with histories of difficult childhoods. The study of hundreds of thousands of women in Sweden found those who as children experienced substance abuse, had a teenage or mentally ill parent, financial problems or a death in the family were linked to a 20% increased risk of an endometriosis diagnosis compared to women who had not been exposed. However, the risk was much greater for girls exposed more than one of those factors, rising to 60%, while those who witnessed or were subjected to violence saw more than twice the risk of developing endometriosis later in life compared to women who had not been exposed, the Swedish authors reported. The study published in the British medical journal Human Reproduction builds on earlier findings that women who experienced physical and sexual abuse as children had a 79% higher risk of developing the painful condition, which affects one in 10 reproductive-age women in the United States. Lead author Dr. Marika Rostvall, a physician and doctoral student in the Department of Global Public Health at the Karolinska Institute in Stockholm, told UPI the findings provide more evidence of the strong connection between mental and physical health. The findings "support previous studies in other areas of medicine suggesting that the mind and body are intimately connected and that psychologically taxing events can have biological consequences," she said in emailed comments. Endometriosis usually affects women in their 20s and 30s, and while there are a handful known risk factors such as starting menstruation early and having a lean body type, the cause remains unknown. The problems stem from the behavior of tissues known as endometrium, which under normal circumstances are found only in the inner lining of a woman's uterus. Those tissues grow to a thick, blood vessel-rich layer during the menstrual cycle to prepare for possible implantation of an embryo, and then shed the blood at the end of the cycle if there is no embryo present. But in some cases, endometrium behave abnormally and start growing outside of the uterus. When they do so, they can attach themselves to the ovaries, fallopian tubes, bowel, bladder or other parts of the body, triggering frequently severe pelvic pain as they carry out their monthly thickening function. As a result, endometriosis can cause excessive bleeding and even infertility -- which is the case for up to half of women with the condition -- as well as cysts, scar tissue and adhesions. Those in turn can trigger chronic pain, including during with sexual intercourse as well as during urination or bowel movements. The Swedish researchers began by looking at the health records of more 1.3 million women born in in the country between 1974 and 2001, eventually narrowing it down to 24,000 who were diagnosed with endometriosis. They then tapped several national registers to track their childhood experiences, looking for evidence of trauma or difficulties, including crimes such as violence and sexual abuse. The results, they said, demonstrate the importance of considering "the whole person" not just the symptoms of endometriosis. The negative physical consequences of psychological trauma can perhaps be traced to a compromised ability of the immune system to protect against the condition, or even in how the body perceives pain, Rostvall said. "I think the immune system is an interesting part of the puzzle when it comes to trying to understand why some women develop endometriosis," she said. "Chronic inflammation is a big part of the disease, and it has also been shown that women with endometriosis have a higher incidence of autoimmune disorders compared to healthy women. "There is a lot of interesting research being done in the area, and a deeper understanding of exactly how the immune system functions in relation to endometriosis could potentially help bring forward new kinds of treatment." Like some other women's health issues, the pain of endometriosis is often dismissed and sufferers have reported negative experiences with healthcare professionals, often in the form of providers "trivializing" symptoms, which can cause feelings of loneliness and alienation. This, in turn, can make obtaining a diagnosis difficult and prompt some to choose to avoid engaging with doctors altogether. A British psychological-based study from last year showed some women who suffered symptoms felt they had experienced a form of "medical gaslighting" in which they were made to doubt their own perceptions of pain. Rostvall said these kinds of experiences are especially relevant when the patients are women who come from socially and psychologically traumatic backgrounds. "A lot of women presenting with pain, especially socioeconomically disadvantaged women and women with psychiatric comorbidities, who are more likely to have experienced childhood adversity, have their pain dismissed. They then have to wait for a long time to receive a diagnosis and treatment, potentially allowing the condition to worsen," she said. "I think physicians should be aware of the complex linkage between the mind and body in general and be more open to listening to their patients' stories, take their pain seriously, and offer a thorough physical examination."
Yahoo
8 hours ago
- Yahoo
China testing orbital refueling procedures for satellite missions
June 10 (UPI) -- China is positioning a satellite to test its ability to refuel another in orbit over Earth and extend its mission for several more years. China's Shijian-25 satellite is designed to refuel and service other satellites while they stay in geostationary orbit over Earth, SpaceNews reported. A geostationary orbit is one in which a satellite or another spacecraft maintains its location over a particular point on Earth by orbiting at a speed that matches the planet's rotation. The satellites were positioned more than 900 miles from each other in low-Earth orbit on Monday. The Shijian-25 was launched in January to test its ability to refuel other satellites and spacecraft, such as the Shijian-21 satellite. Shijian-21 was launched in October 2021 and has already completed its mission to dock with the Beidou-2 G2 navigation satellite and tow the defunct satellite to a so-called "graveyard orbit." Such an orbit positions defunct satellites well above geostationary orbit, so it won't interfere with active satellites. Two U.S. satellites are monitoring the two Chinese satellites, which completed several maneuvers over the past weekend to close the gap between them. The Chinese satellites are expected to dock on Wednesday and start a refueling procedure the test the viability of refueling satellites and other spacecraft while they are in geostationary orbit. If the test is successful, it means satellites could extend their missions for much longer than they initially were designed. The Shanghai Academy of Spaceflight Technology designed the two satellites, and the Shijian-21 appeared to run out of fuel until its recent maneuvers to close the distance between it and the Shijian-25. If the two satellites successfully dock with one another, the Shijian-25 is expected to transfer 313 pounds of hydrazine to extend Shijian-21's service life by another eight years. The test is similar to one planned by U.S.-based Northrop Grumman, which intends to launch its Mission Robotic Vehicle next year to conduct similar servicing of U.S. satellites and spacecraft.


UPI
10 hours ago
- UPI
China testing orbital refueling procedures for satellite missions
China launched its Shijian-25 satellite in January and has scheduled a Wednesday rendezvous with another satellite to test an in-orbit refueling procedure. File Photo by Wang Jiangbo/EPA-EFE June 10 (UPI) -- China is positioning a satellite to test its ability to refuel another in orbit over Earth and extend its mission for several more years. China's Shijian-25 satellite is designed to refuel and service other satellites while they stay in geostationary orbit over Earth, SpaceNews reported. A geostationary orbit is one in which a satellite or another spacecraft maintains its location over a particular point on Earth by orbiting at a speed that matches the planet's rotation. The satellites were positioned more than 900 miles from each other in low-Earth orbit on Monday. The Shijian-25 was launched in January to test its ability to refuel other satellites and spacecraft, such as the Shijian-21 satellite. Shijian-21 was launched in October 2021 and has already completed its mission to dock with the Beidou-2 G2 navigation satellite and tow the defunct satellite to a so-called "graveyard orbit." Such an orbit positions defunct satellites well above geostationary orbit, so it won't interfere with active satellites. Two U.S. satellites are monitoring the two Chinese satellites, which completed several maneuvers over the past weekend to close the gap between them. The Chinese satellites are expected to dock on Wednesday and start a refueling procedure the test the viability of refueling satellites and other spacecraft while they are in geostationary orbit. If the test is successful, it means satellites could extend their missions for much longer than they initially were designed. The Shanghai Academy of Spaceflight Technology designed the two satellites, and the Shijian-21 appeared to run out of fuel until its recent maneuvers to close the distance between it and the Shijian-25. If the two satellites successfully dock with one another, the Shijian-25 is expected to transfer 313 pounds of hydrazine to extend Shijian-21's service life by another eight years. The test is similar to one planned by U.S.-based Northrop Grumman, which intends to launch its Mission Robotic Vehicle next year to conduct similar servicing of U.S. satellites and spacecraft.