Scientists Identify the Biological Memory That Makes Obesity Relapse So Hard to Prevent
Key Takeaways:
- Researchers have identified a lasting biological change in fat cells – an “obesity memory” – that keeps the appetite-stimulating hormone asprosin elevated even after a person or animal has lost the excess weight.
- The same inflammatory signal can cross the placenta, programming a baby’s fat cells before birth and offering a molecular explanation for why obesity risk can pass from mother to child across generations.
- Blocking the asprosin pathway in mice prevented both weight regain after dieting and inherited obesity risk, suggesting a potential complementary target to use alongside or after GLP-1 receptor agonist treatment.
Two long-standing puzzles in obesity research
Two biological mysteries have resisted explanation for decades. The first is why almost everyone who loses weight eventually regains it, regardless of the method used to lose it. The second is why obesity is transmitted from mother to child at rates that diet and environment alone cannot account for. Scientists from the Harrington Discovery Institute at University Hospitals and Case Western Reserve University now believe they have identified the reason behind both.
In a study published in Cell Reports, the research team found that obesity produces a durable biological change within fat cells that keeps the hunger hormone asprosin elevated – a phenomenon the researchers describe as “obesity memory” – even once weight has been lost. The findings may help to explain why many people regain weight after dieting or after discontinuing GLP-1 medications, and why obesity risk can persist from one generation to the next.
An appetite signal stuck in the on position
“Imagine having an appetite-stimulating signal stuck in the ‘on’ position day after day, despite losing weight,” explained Atul Chopra, M.D., Ph.D., senior author of the study, investigator and associate director of the Harrington Rare Disease Program at Harrington Discovery Institute at UH, and associate professor of medicine, genetics and genomics at Case Western Reserve University School of Medicine.
“Our findings suggest one reason weight regain can be so difficult to prevent after treatment ends. This same signal can also cross the placenta from mother to baby. The result is a child born with a programmed susceptibility to obesity. This may also explain why obesity became an epidemic and why the cycle has continued for generations.”
The observation that weight regain and intergenerational risk are near-universal features of obesity is not new. What has been missing is the underlying molecular explanation.
“These patterns have been observed for decades, but nobody knew the exact molecular mechanism that makes obesity so persistent or how it transmits across generations,” Chopra added. “We wanted to find the biological basis for that persistence.”
A switch that stayed on
The team began the study by looking for what turns up production of the hunger hormone asprosin in obesity. They identified an inflammatory signal, TGF-β1, as the trigger. The most striking result was that only a brief exposure to that signal was required to create a lasting change, one that persisted for weeks after the signal itself had disappeared.
“It was like flipping a light switch that stays on even after you remove your finger,” Chopra said. “Even after mice lost all the excess weight and TGF-β1 returned to normal, this switch in their fat cells remained flipped, keeping asprosin and appetite elevated.
“This gives us a molecular explanation for why GLP-1 drugs, which suppress appetite while you take them, cannot fix the underlying biological memory that drives hunger back up once treatment ends. This same signal crosses the placenta and programs a baby’s fat cells before birth.”
In other words, the change in fat tissue is epigenetic rather than temporary. The cells retain a record of the obesity they were exposed to, and that record continues to drive hunger long after body weight has normalised.
What this means for GLP-1 therapy
The mechanism offers an explanation for a pattern already familiar to clinicians: people taking GLP-1 medications frequently regain weight once they discontinue treatment. The medication suppresses appetite for as long as it is taken, but it does not erase the epigenetic memory held in fat cells. When the pharmacological brake is released, the underlying appetite signal is still switched on.
This has practical implications for how GLP-1 therapy is planned, discussed and supported in practice, particularly around the point of discontinuation. Structured professional development in this area – such as the College of Contemporary Health’s GLP-1RA Therapy: The Complete Programme short course – can help clinicians set realistic expectations with patients from the outset and plan for the period after treatment ends, rather than treating regain as an unexpected failure.
Pharmaceutical companies are actively searching for ways to help people maintain weight loss once treatment stops. The new findings identify a potential complementary target: a pathway that may sustain the biological drive towards regain after weight reduction.
Blocking asprosin changed the outcome
The researchers also tested what happened when the asprosin pathway was interrupted in mice, from the gene that produces the hormone through to the receptor in the brain that responds to it. Blocking this pathway prevented both weight regain after dieting and the inherited obesity risk passed to offspring.
That result points towards new therapeutic strategies aimed directly at the relapse problem that drug developers are currently trying to solve.
Evidence beyond a single laboratory
The study was deliberately designed to test its central observation outside the laboratory that made it. A separate laboratory led by Seth J. Field, M.D., Ph.D., independently reproduced the key persistence finding. Field is director of physician-scientist programs and chief scientific officer at the Harrington Discovery Institute at UH and a professor at Case Western Reserve School of Medicine.
Analyses of publicly available mouse and human datasets produced further supporting evidence. Additional human research is still needed, but the convergence across separate laboratories and independent datasets strengthens the case that this mechanism warrants serious investigation.
A message for clinicians
Chopra said the central message for clinicians is that obesity relapse is not a failure of willpower or discipline. It is driven by a durable biological memory written into fat tissue, which sustains hunger long after the weight has come off.
“We need to treat obesity as a condition that leaves lasting biological scars, not just a temporary state of excess weight,” he said.
Framing obesity in these terms has consequences for how conversations with patients are conducted. If regain reflects a persistent biological signal rather than a lapse in personal effort, then the clinical focus shifts towards long-term management and realistic planning for the period after active treatment.
Turning to human trials
The critical next step is translating these findings into people. The researchers plan to confirm that the same epigenetic memory operates in human fat tissue after weight loss, and to test whether therapies that block asprosin, or that reset these epigenetic marks, can prevent weight regain in people.
“Given the need for durable obesity treatments, we are interested in whether asprosin-blocking therapies could be used alongside or after GLP-1 treatment to prevent rebound,” Chopra concluded.
CCH insight
Research of this kind is changing how weight regain is understood and discussed in the consultation room. The College of Contemporary Health’s GLP-1RA Therapy: The Complete Programme CPD short course is designed for healthcare professionals who prescribe or support people using GLP-1 receptor agonists, including the practical questions that arise around initiation, ongoing support and discontinuation.
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