There is suggestive evidence that some forms of religious fasting are associated with health benefits that could contribute to longer, healthier lives, but the link to true longevity is not yet proven and likely depends on the type of fasting, the person, and other lifestyle factors. [2][4]
Religious fasting comes in many forms and is common across traditions. Examples include Ramadan daytime fasting in Islam (daily abstention from food and drink for a month), Orthodox Christian fasts that restrict animal products for extended periods, periodic Daniel-style fasts in some Protestant communities, and voluntary periodic fasts inspired by Buddhist or Hindu practices. These practices vary by length, timing, calorie restriction, and permitted foods, so their physiological effects are not identical.[5][2]
How fasting could affect health and aging
– Metabolic changes: Fasting reduces the time the body spends in a fed, insulin-stimulated state, lowering insulin and sometimes blood glucose and IGF-1 signaling, which are pathways linked to aging in animal studies.[2][4]
– Cellular repair pathways: Periods without food can trigger autophagy, a cellular “cleanup” process that removes damaged components and is implicated in aging biology; recent clinical work shows fasting-mimicking diets can activate autophagy-related processes in humans and improve metabolic markers.[1][3]
– Weight and cardiometabolic risk: Many intermittent fasting patterns produce calorie reduction and weight loss, reducing abdominal fat, blood pressure, and some risk scores tied to cardiovascular disease, which is a major determinant of lifespan.[2][3]
– Immune and inflammatory effects: Fasting can lower some inflammatory markers and influence immune function in ways that may protect against chronic disease, although effects differ by fasting protocol and study population.[2]
What the evidence from religion-linked fasting shows
– Ramadan studies provide a real-world model of daily time-restricted feeding (roughly 12 to 18 hours daily for a month). Clinical work finds short-term benefits such as small weight loss and improvements in some metabolic markers, and adaptive changes in appetite over the month, but long-term effects on mortality or maximum lifespan are not established.[5]
– Observational studies of religious groups who practice regular fasting sometimes report better health and longer life, but those findings are hard to interpret because religious fasting is tied to other healthy behaviors (community support, lower smoking, different diets) that confound results.[4]
– Interventions that mimic periodic prolonged fasting (for example, 5-day fasting-mimicking diets tested in clinical trials) show promising changes in biomarkers of aging, metabolic health, and autophagy activation, suggesting a possible mechanism linking periodic fasting to healthy aging; these trials are early and focused on biomarkers rather than hard longevity outcomes.[1][3]
Limitations, uncertainties, and risks
– Most direct evidence for lifespan extension comes from animal models exposed to strict calorie restriction or fasting regimens; translating animal longevity gains to humans is uncertain because of differences in physiology, timescale, and exposure levels.[2][4]
– Human trials so far focus on intermediate outcomes (weight, blood pressure, glucose control, inflammatory markers, biological age scores) rather than decades-long survival data, so claims about increased lifespan remain inferential.[1][2]
– Forms of religious fasting differ in duration, nutrient composition during feeding windows, and cultural practices; benefits seen in one fasting model may not apply to another.[5]
– Fasting is not risk free: people with certain conditions (pregnancy, type 1 diabetes, eating disorders, some chronic diseases) can be harmed by fasting and should consult healthcare providers before undertaking it.[6]
– Observational links between religious fasting and longevity can be biased by other healthy behaviors common in religious communities, making causal attribution difficult.[4]
Practical takeaways grounded in current evidence
– Time-restricted and periodic fasting can improve metabolic health markers for many people and activate cellular repair pathways implicated in aging, which supports the biological plausibility of a link to healthier aging if practiced safely and appropriately.[1][2][3]
– Religious fasting practices that are moderate, supported by adequate nutrition during nonfasting periods, and integrated with overall healthy habits may offer health advantages beyond spiritual benefits; however, they should not be assumed to guarantee longer life by themselves.[5][4]
– Anyone considering more extreme fasting protocols or fasting-mimicking diets should discuss this with a clinician, especially if they have underlying health conditions or take medications that affect blood sugar, blood pressure, or hydration.[6]
Sources
https://www.prnewswire.com/news-releases/first-ever-human-trial-finds-fasting-mimicking-diet-enhances-autophagy-while-improving-metabolic-health-302643077.html
https://pmc.ncbi.nlm.nih.gov/articles/PMC12675562/
https://doc.health/doc-2025-video-how-to-fuel-longevity/
https://time.com/collections/future-of-living/7341846/aging-research-nir-barzilai-longevity/
https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2025.1718105/full
https://economictimes.com/magazines/panache/fasting-is-not-a-miracle-cure-apollo-neurologist-busts-popular-myths-revealing-what-it-really-does-for-your-health/articleshow/126058271.cms
