Is there evidence that fasting slows aging? Yes, studies in animals and early human trials show promising signs that fasting and related methods like intermittent fasting or fasting-mimicking diets trigger body processes linked to longer, healthier lives. These include better cell cleanup, lower inflammation, and changes in hormones tied to aging.
Fasting means going without food for periods, from a day to several days. It forces the body to switch fuels, burning fat for energy and producing ketones. This shift activates autophagy, where cells recycle old parts, much like cleaning house to stay efficient. A recent human trial found that a fasting-mimicking diet, which uses low-calorie plant foods to mimic water fasting, boosted autophagy markers in people. https://www.morningstar.com/news/pr-newswire/20251216la48282/first-ever-human-trial-finds-fasting-mimicking-diet-enhances-autophagy-while-improving-metabolic-health Scientists call this a key anti-aging tool because poor autophagy speeds up cell damage and diseases like diabetes or heart issues.
In animals, the proof is stronger. Rodents and flies on calorie cuts or fasting live longer with fewer cancers and better brain function. One study switched older fruit flies from high to low calories, slowing their aging rate and extending life even late in life. https://www.pnas.org/doi/10.1073/pnas.2311019120 Mice on repeated fasting-mimicking cycles had more stem cells, less cancer, and sharper cognition. These effects come from lower IGF-1 and growth hormone levels, plus boosted mitochondrial health, which fights oxidative stress, a main aging driver. https://pmc.ncbi.nlm.nih.gov/articles/PMC12736288/
Humans show benefits too, though not direct lifespan proof yet. A six-month trial with middle-aged adults doing vegetable-only fasting two to three days a week cut body fat by 16 percent, dropped bad cholesterol, and improved lipid profiles. https://pmc.ncbi.nlm.nih.gov/articles/PMC12727815/ Fasting-mimicking diets lowered IGF-1, blood pressure, and body weight in healthy people, plus helped type 2 diabetes patients control blood sugar with less medicine. https://www.elle-md.com/why-the-fasting-mimicking-diet-is-worth-considering-in-the-new-year Older adults on intermittent fasting scored better on thinking tests, with blood markers of repair processes up.
Prolonged fasting also tweaks thyroid and blood pressure systems to cut inflammation and stress, mimicking calorie restriction that extends life in labs. But human studies are short-term, so experts want more long-term data to confirm if these changes truly slow human aging.
Sources
https://pmc.ncbi.nlm.nih.gov/articles/PMC12736288/
https://www.morningstar.com/news/pr-newswire/20251216la48282/first-ever-human-trial-finds-fasting-mimicking-diet-enhances-autophagy-while-improving-metabolic-health
https://www.pnas.org/doi/10.1073/pnas.2311019120
https://www.elle-md.com/why-the-fasting-mimicking-diet-is-worth-considering-in-the-new-year
https://pmc.ncbi.nlm.nih.gov/articles/PMC12727815/
