🍽️ It's not intermittent fasting that prolongs life, but what happens right after...

Intermittent fasting is associated with extending lifespan. However, a recent study from UT Southwestern challenges this idea: the benefits actually come from the refeeding phase, not from the deprivation.

C. elegans worms are valuable models in laboratories: they age quickly and share many genes with humans. Subjecting them to a 24-hour fast led to a 41% increase in their lifespan. But the most surprising result involved a protein called NHR-49, which manages fat burning during fasting. Contrary to expectations, the absence of this protein did not reduce the longevity benefit. This shifted research focus toward what happens after the fast.


Normally, when food becomes scarce, NHR-49 activates and instructs cells to draw on their fat reserves. Once food returns, this activity must cease. The researchers created genetically modified worms in which NHR-49 remained active even after eating. The result was clear: the beneficial effect of fasting on longevity disappeared entirely. Therefore, stopping lipid degradation is a critical step to reap the benefits.

The findings indicate that the ability to halt lipid degradation after fasting is more important than the fast itself. This discovery could lead to interventions targeting this metabolic pathway, for instance by modulating the activity of the enzyme KIN-19. Thus, it would be possible to obtain the benefits of fasting without following strict diets, representing a major advance for human health.

According to Dr. Peter Douglas, co-lead author of the study, this work links lipid metabolism to aging research. By tackling aging itself—the main risk factor for many diseases—one could develop preventive medicine that improves quality of life. The next steps will involve verifying whether these mechanisms apply to humans and exploring ways to target them therapeutically.