New research suggests that obesity can leave lasting epigenetic changes in immune cells, meaning the body may take years to fully recover even after excess weight is lost.
A new study published in the journal EMBO Reports has revealed that losing excess weight does not mean that the immune system immediately returns to normal. It may take many years of consistently maintaining the weight that has been lost.
The precise issue lies in a chemical mark left by obesity on a specific type of white blood cell known as “CD4 T” lymphocytes, which are the main regulators and drivers of the adaptive immune response in the human body.
This newly identified chemical mark is a biological process known as “DNA methylation.” It is a genetic mark that affects the genome, changing how genes are read and used without altering the genetic code itself.
According to the scientific analysis, obesity imposes a precise genetic pattern that remains embedded in these immune cells even after the excess weight has been completely lost.
The diet extends until chronic inflammation is calmed (Pexels)
Immune regulation does not return to its normal level, leaving the body more vulnerable to chronic inflammation and making it easier to regain weight due to cellular biological mechanisms that have nothing to do with an individual’s behavior or daily personal choices.
Researchers attribute this unusual mechanism to two main processes: autophagy and cellular immune senescence, in which cells stop dividing and begin releasing harmful inflammatory mediators.
The researchers expect that it could take between five and 10 years for the immune system to fully recover. However, this estimate remains a theoretical assumption based on a mechanism established in mice and has not yet been confirmed by long-term studies in humans.
Genetic battle against inflammatory memory (Pexels)
These findings are particularly significant today, amid the widespread use of modern weight-loss medications, as they show that rapid weight loss does not mean that health risks disappear immediately. Rather, the immune response requires much more time.
Dietitian Gaëlle El Helou explains that epigenetic changes may be affected by changes in weight without altering the sequence of the genes themselves, but rather the way they function and their level of activity.
After losing weight, the body may undergo hormonal and metabolic changes, such as increased feelings of hunger and reduced satiety signals, which may make it more difficult to maintain the lost weight.
This response can be understood, in simple terms, through the concept of “body memory.” However, considering it a form of “genetic memory” directly linked to weight regain still requires further research and has not been conclusively established in humans.
Regaining weight is not a failure of willpower (Agencies)
El Helou points out that losing weight gradually and in a balanced manner, while meeting the body’s nutritional needs and avoiding severe restriction, helps maintain the lost weight over the long term.
These medical facts should not be a reason for frustration or for giving up on weight loss. Rather, they are compelling evidence that weight regain is not a failure of willpower, but may be linked to complex biological mechanisms in the body. It should be noted, however, that the concept of “genetic memory” and its role in weight regain still requires further scientific evidence in humans.
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