Researchers at the University of Michigan have reported that the sensation of hunger itself can trigger the rejuvenating effects of fasting, even when the total calorie intake isn’t reduced. The study appears in Science.
Earlier work in fruit flies and rodents showed that restricting calories could extend lifespan and improve health markers. Yet translating these findings to humans requires caution, as results can vary between studies and may carry potential risks that demand further investigation.
The new study suggests that simply experiencing hunger may be enough to slow the aging process, independent of the actual caloric content of the diet.
Branched-chain amino acids (BCAAs) are essential nutrients known to contribute to feelings of fullness in fruit flies. In the experiment, researchers fed hungry flies snacks low in BCAAs, then allowed access to normal food after a few hours. The hungry flies consumed more overall and showed a preference for high-protein foods over high-carbohydrate options, indicating that hunger was driving their eating choices rather than mere taste or appetite.
Remarkably, the same patterns emerged as when the diet’s calorie level was deliberately restricted. Even more striking, hungry flies that had their hunger-triggering neurons artificially activated tended to live longer, suggesting a direct link between hunger signals and longevity in this model organism.
From these observations, the team concluded that hunger itself can slow aging, not simply the energy content or availability of nutrients in a meal. This points to the brain’s hunger circuits as key intermediaries in the aging process, at least in the studied species.
The findings may illuminate why low-BCAA dietary approaches have shown health benefits. These diets can provide necessary nutrients while preserving hunger signals that help regulate intake, potentially avoiding complete suppression of appetite. Such an approach could support balanced nutrition while still engaging metabolic pathways associated with longevity.
However, the researchers emphasize caution. Much more work is needed before applying these results to people. While many genes involved in aging are shared between fruit flies and humans, demonstrations of safety and effectiveness in mammals and, ultimately, in humans are essential before any clinical recommendations can be made. Continued research will be required to determine whether similar hunger-driven longevity effects occur in higher organisms and under what conditions they might be safe and beneficial in humans. (Source: Science, contemporary aging research reports)