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Intermittent Fasting For Longevity: What Does Science Say?
Updated on
- Written by Heather Freudenthal, Health Coach
Medically reviewed by
Dr. Maya Frankfurt, PhD
Intermittent fasting (IF) is the practice of alternating between periods of eating and periods of fasting. Periods of eating and fasting can be broken up in different increments. The benefits of IF on hormone balance and weight loss are known, but there is more to be obtained from IF. For example, intermittent fasting for diabetics and intermittent fasting for working out. While some evidence suggests IF can have positive impacts on longevity, more research is still needed.
The foods we choose during feeding windows matter, too. It can be useful to know the intermittent fasting food list to help maximize the effects of IF. To get the most out of IF, consider the best intermittent fasting app, which includes DoFasting. Read the DoFasting reviews to get more insight.
Does Intermittent Fasting Lead To A Longer Lifespan?
While intermittent fasting may extend lifespan[1], research is both limited and inconclusive. The benefits of IF on various aspects of health can have larger, positive influences over time, however, more research is needed to connect these factors. For example, some research demonstrates that IF can improve insulin sensitivity and decrease inflammation, both of which can reduce risk of age-related disease, but the direct impact of IF on longevity has yet to be determined.
What Does Science Say About Intermittent Fasting & Longevity?
Scientific studies vary in finding a potential link between intermittent fasting and longevity. Some animal studies show a possible correlation between intermittent fasting and longer life spans[2], as well as improved health, such as better insulin sensitivity[3], reduced inflammation, and reduced anxiety and stress[4]. However, human studies are lacking.
Intermittent fasting may play a role in some of the mechanisms involved in aging, such as cellular recycling, insulin sensitivity, and stress recovery. While these are correlated with better long-term health, it is difficult to conclusively state that intermittent fasting extends lifespan.
6 Impacts Of Intermittent Fasting For Longevity
Weight Loss
Intermittent fasting has gained popularity as an effective weight loss method[5]. It can influence weight loss not only via calorie restriction, but by its potential to increase fat burning. When glycogen stores (sugar stored in the liver) are low during fasting periods, the body uses fat for energy. Just be sure not to overdo it on food during eating periods.
Improved Insulin Sensitivity
Some studies indicate that blood glucose levels and insulin sensitivity can be improved with IF[6]. Ideally, we should be very sensitive to insulin, so that it can do its job: move sugar from our food into our cells for energy. However, high-sugar diets, among other factors, can decrease our sensitivity to insulin, making it less effective (insulin resistance), which can result in high blood sugar and type 2 diabetes.
Reduced Inflammation
Time restricted feeding may also reduce inflammation[7] in the body, which can have positive ripple effects on overall health. Inflammation is a driving force behind ailments, big and small, from acne to cancer to arthritis.
Cellular Repair
We all need rest and repair on a cellular level[8] and IF can help with that. During periods of fasting, the body goes through autophagy[9], or recycling and removing damaged cells. When we are able to give the body more periods of rest between eating, we allow this process to happen more frequently, which can have positive effects on aging.
Improved Brain Function
Intermittent fasting may also play a positive role in cognitive function, by increasing BDNF[10], or brain-derived neurotrophic factor, a protein responsible for the growth and upkeep of brain cells, as well as promoting neuroplasticity. This translates to better mood, memory, clarity, and concentration, and less risk for Alzheimer’s Disease.
Improved Heart Health
Engaging in time restricted feeding may also improve heart health through better blood pressure, cholesterol, and triglyceride levels. Together, improved heart health[11] markers could reduce risk of cardiovascular disease and stroke.
How Long Should You Fast For Longevity?
Intermittent fasting for longevity, specifically, has mixed results. This makes it difficult to quantify its direct longevity benefits and to pinpoint a specific amount of time to fast. Different variations of intermittent fasting suggest varying periods of fasting. A few variations of IF[12] include:
- Time-restricted fasting, or TRF, such as the 16:8 method. This means you have an 8-hour feeding window each day followed by a 16-hour period of fasting. Another version of time restricted feeding is 14:10.
- Alternate day fasting. This method involves alternating eating and fasting every other day, or going one full day without eating, followed by one day of eating, then going back to fasting the following day (and so on).
- The 5:2 method. This approach to fasting suggests that you eat normally for five consecutive days (say, Monday through Friday), then fast for two consecutive days (say, Saturday and Sunday). Caloric intake of up to 600 calories is permitted on the fasting days.
Can You Do Intermittent Fasting for Longevity Every Day?
Yes, some methods of IF can be done everyday. The easiest and safest way to practice IF daily is to do a time-restricting one, such as 14:10 or 16:8. This allows a feeding window and a fasting period each day. This is considered a safe practice for most individuals, whereas other methods of fasting which require longer fasting periods may not be suitable to do daily.
Tips To Do Successfully Intermittent Fasting for Longevity
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Any time you change your eating approach, especially when it involves restricting calories in ongoing intervals, it should be done responsibly in order to be successful in your goals.
Start Small
When you undertake a new eating approach, it is not advisable to jump into the deep end. You don’t know how your body will react, so start slow. Choose a time period and amount of time to fast, but aim lower than the recommended amount. For example, if you want to fast for 16 hours overnight, aim for 12 hours for a week and see how you do. If that works for you, build up to 13 hours, and so on until you reach 16 hours.
Choose Wisely
There are many variations of IF, such as alternate day fasting, 5:2 and time-restricting fasting. You may need to experiment with a few variations before you find one that is suited to your body. Do not jump into a method that works for others or seems trendy. Really take the time to tune into what your body needs.
Work With A Practitioner
Any change in eating approach, especially one that involves fasting, should be overseen by a qualified practitioner. If your doctor is not familiar with IF, find another doctor or nutritionist who is. As IF can influence health and disease processes, make sure you continually monitor your health with a professional, and adjust your eating routine as needed.
Get Enough Nutrients
Restricting feeding times overlaps with calorie restriction. Remember that when we restrict eating, we restrict calories, at least for those fasting periods, but this also means a restriction of essential nutrients. Be sure to eat well-balanced, whole food-based meals during your feeding windows.
Hydrate
With IF, so much of the emphasis is on food, when to eat and when not to eat. Don’t lose sight of the importance of hydration. Be sure to stay hydrated throughout the day, especially during fasting periods.
Watch Your Portion Sizes
Although the principles of IF fasting are composed of extremes, eating and fasting, we want to avoid overdoing it during feeding windows. IF can cause hunger, which means we may be compelled to overeat or even binge during our feeding windows. Not only might we eat more than is good for us, but our food choices may not be as healthy. Be mindful to eat normal sized, evenly spaced, healthy meals during feeding windows.
Maintain A Healthy Lifestyle
No dietary approach, including IF, is enough by itself to improve lifespan. Do not overlook the importance of an all-around healthy lifestyle in order to add more, healthy years onto your life. This includes exercising, sleeping well, hydrating, managing stress, seeking joy, eating whole foods, spending time in nature, and reducing alcohol.
Conclusion
There are many health benefits of intermittent fasting (IF), the practice of alternating between periods of eating and periods of restricting food. Many methods of IF have been shown to improve various health markers including inflammation, body weight, brain health, cardiovascular disease, and blood sugar, putting us at less risk for chronic disease. Though these factors can help us maintain vitality as we age and reduce risk of age-related diseases, there is no current definitive link between intermittent fasting and longevity.
Frequently Asked Questions
Many IF approaches suggest only having water during fasting periods, however, when fasting for full, or even consecutive days (as with the 5:2 method), a small amount of calories are allowed (as much as 600 calories per day). But these rules are not set in stone, always listen to your body, and if you need to eat, eat.
No. Pregnant women should not try intermittent fasting. The needs of a pregnant woman and her growing fetus are not compatible with intermittent fasting.
You can certainly shift your fasting window to align with overnight hours. In fact, that is the easiest for many people to engage in prolonged fasting, because they are asleep and will not feel hungry during this time.
+ 12 sources
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- Dae Sung Hwangbo, Hye Sun Lee, lobaina mohammed abozaid and Kyung Jin Min (2020). Mechanisms of Lifespan Regulation by Calorie Restriction and Intermittent Fasting in Model Organisms. [online] 12(4), pp.1194–1194. doi:https://doi.org/10.3390/nu12041194.
- https://www.facebook.com/NIHAging (2020). Research on intermittent fasting shows health benefits. [online] National Institute on Aging. Available at: https://www.nia.nih.gov/news/research-intermittent-fasting-shows-health-benefits.
- Yuan, X., Wang, J.-D., Yang, S., Mei Hua Gao, Cao, L., Li, X., Hong, D., Tian, S. and Sun, C. (2022). Effect of Intermittent Fasting Diet on Glucose and Lipid Metabolism and Insulin Resistance in Patients with Impaired Glucose and Lipid Metabolism: A Systematic Review and Meta-Analysis. [online] 2022, pp.1–9. doi:https://doi.org/10.1155/2022/6999907.
- Berthelot, E., Etchecopar-Etchart, D., Dimitri Thellier, Christophe Lançon, Boyer, L. and Fond, G. (2021). Fasting Interventions for Stress, Anxiety and Depressive Symptoms: A Systematic Review and Meta-Analysis. [online] 13(11), pp.3947–3947. doi:https://doi.org/10.3390/nu13113947.
- Sek Ying Chair, Cai, H., Cao, X., Qin, Y., Ho Yu Cheng and Ng, M.K. (2022). Intermittent Fasting in Weight Loss and Cardiometabolic Risk Reduction: A Randomized Controlled Trial. [online] 30(1), pp.e185–e185. doi:https://doi.org/10.1097/jnr.0000000000000469.
- Sutton, E.J., Beyl, R.A., Early, K., Cefalu, W.T., Ravussin, E. and Peterson, C.M. (2018). Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. [online] 27(6), pp.1212-1221.e3. doi:https://doi.org/10.1016/j.cmet.2018.04.010.
- Mayo Clinic. (2022). Is intermittent fasting good for you? [online] Available at: https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/intermittent-fasting/faq-20441303#:~:text=Some%20research%20suggests,Stroke.
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Written by:
Heather Freudenthal, Health Coach
Medically reviewed by:
Medically reviewed by:
