Study finds that fruit flies, when induced to feel hungry, end up living longer even when ample calories are consumed.
According to the findings of a recent study conducted by researchers from the University of Michigan in the US, it is suggested that the anti-aging effects of intermittent fasting can be triggered solely by the perception of insatiable hunger. The need for the organism to actually starve is not necessary.
“The life-extending effects of diet restriction, which researchers had focused on for many years, can be separated from nutritional manipulations,” says physiologist Scott Pletcher. “The perception of insufficient food is adequate.”
Intermittent fasting has gained popularity as a dietary trend in recent years, although the evidence supporting its benefits is currently limited and primarily based on animal studies.
Studies on fruit flies (Drosophila melanogaster) and rodents indicate that calorie restriction can extend lifespan and promote good health. However, further extensive research is required before these results can be applied to humans, especially considering conflicting findings and potential risks identified in some studies.
To delve deeper into the molecular mechanisms of fasting, the researchers of this latest investigation once again chose the humble fruit fly.
In the past, studies on fruit flies have aided scientists in identifying numerous neural signals in the brain related to hunger and satiety. These creatures share 75 percent of the same disease-related genes as we do, and their metabolisms and brains exhibit useful similarities to those found in mammals.
Feelings of fullness in flies seem to be triggered by the consumption of branched-chain amino acids (BCAA), which are essential nutrients. Therefore, increasing BCAA intake reduces their hunger sensations.
To investigate how this might impact the aging process, fruit flies were kept in a state of hunger by providing them with snacks low in BCAA.
The researchers measured their hunger levels based on the amount of food the insects consumed from a buffet of options several hours after having the snack.
Flies that received a low-BCAA snack consumed more food during the subsequent buffet. They also displayed a preference for protein-rich foods over carbohydrate-rich foods, indicating that their hunger was driven by necessity rather than desire.
Consequently, the researchers decided to target the source directly. When the team activated the neurons in fruit flies responsible for triggering hunger responses, they discovered that these stimulated flies also had longer lifespans.
“Thus,” it is stated by Pletcher and colleagues, “the process of slowing down aging might be influenced by the state of hunger itself, rather than the availability or energetic characteristics of the diet.”
Additional experiments revealed that reducing BCAA levels in the diets of flies resulted in their hunger neurons producing modified support proteins known as histones. These histones bind to DNA and assist in regulating gene activity. The researchers propose that these modified histones could be the connection between diet, hunger responses, and aging. Interestingly, previous studies have linked an increased supply of histones to a longer lifespan.
Based on the findings, researchers speculate that chronic hunger could be an adaptive response that “slows aging through modifications to histone proteins in specific neural circuits.”
These findings may offer insights into why low-BCAA diets appear to be beneficial for our overall health. It is possible that such diets provide the body with adequate nutrients without completely suppressing hunger signals in the brain.
Naturally, this idea requires extensive testing. Relying solely on one study involving fruit flies is insufficient.
Currently, the researchers are interested in investigating whether the well-being of fruit flies is influenced by both pleasurable and necessary eating experiences.