Is Intermittent Fasting the Key to Longevity?

Written and medically reviewed by Rich LaFountain, PhD

Everyone wants to live better, longer. The question is: How?

Intermittent fasting has gained considerable attention in recent years for its many health benefits — but is it the key to healthy longevity? Let’s take a look at what a rapidly-growing field of research says about intermittent fasting for longevity.

Does Intermittent Fasting Lead to a Longer Lifespan?

Decades of research confirm that caloric restriction contributes to a longer lifespan in animals and in humans. More specifically, caloric restriction without malnutrition is the most consistent way to use food to extend life over the long term. But lifespan extension is only part of the equation. If you truly want to maximize your longevity, you want to stay healthier while living longer. Intermittent fasting can help you achieve this without the challenges of pure caloric restriction. 

5 Powerful Impacts of Intermittent Fasting for Longevity

Intermittent fasting longevity results, in part, from creating spontaneous caloric restriction that is sustainable because it is not accompanied by the feelings of deprivation that come with chronic calorie restriction. There are other advantages, too. For starters, intermittent fasting helps you maintain a healthy weight — an essential part of warding off chronic disease and other life-shortening conditions. Intermittent fasting also shifts your body’s fuel preference towards burning fat, which keeps your cells metabolically healthy and flexible. Healthy, metabolically flexible cells are resilient to stress, illness, and disease. Ultimately, intermittent fasting keeps the billions of cells in your body in good health and on the path towards healthy longevity. 

#1. Intermittent Fasting Helps You Maintain a Healthy Weight

Epidemiological studies suggest that over 75% of American adults are overweight or obese — and that figure is expected to grow. Meanwhile, studies show that, on average, people eat or snack during 14–15 hours of their 24-hour day. If you follow this schedule, your body may never get a chance to shift your metabolism and fully activate your innate fat-burning machinery.

When your body is out of balance and exclusively operating in the fed metabolic state (growth mode), you are more likely to gain weight. Researchers have found that unrestricted meals and snacks, a.k.a. “grazing,” often leads to lower diet quality, higher caloric intake, and more late-night eating. Consequently, round-the-clock eating patterns have been linked to weight gain and declines in metabolic health. Intermittent fasting enables your body to naturally balance fed vs. fasted metabolism. Compared with restrictive diets that require a lot of discipline, intermittent fasting is a more sustainable lifestyle approach to maintaining healthy body weight and may be superior for weight loss.

#2. Intermittent Fasting Reduces Oxidative Stress

Intermittent fasting is an excellent way to reduce overall oxidative stress, which otherwise damages your DNA and causes you to age faster. In a three-year follow-up study of adults over 60 years old, intermittent fasting just a couple times a week was shown to naturally reduce inflammation and boost natural anti-aging processes. Similarly, a recent study demonstrated that daily intermittent fasting in the form of time-restricted feeding (an eating schedule that is contained within a shortened set of consecutive hours) reduced oxidative stress markers by 25–31%. In a nutshell, intermittent fasting helps protect your DNA and thereby promotes longevity at the cellular level. 

#3. Intermittent Fasting Fights Chronic Inflammation

Chronic inflammation is believed to be a causal factor in atherosclerotic disease (which can lead to heart attacks) and insulin resistance. Ergo, reduce chronic inflammation and you’ll increase your chances of healthy longevity. Intermittent fasting has been shown to reduce circulating inflammation markers more effectively than alternative strategies like calorie restriction. As your metabolism shifts to burning fat and producing ketones, you activate anti-inflammatory pathways that are turned off in the fed state. Previous studies demonstrating this mechanism are supported by a new study that identified intermittent fasting as an effective method to improve insulin sensitivity, gut microbiome health, and overall inflammation throughout the body. 

#4. Intermittent Fasting Protects Against Age-Related Disease

A significant body of evidence suggests that fasting regimens, especially in middle-aged adults and older, protect against common age-related diseases, like heart disease. Researchers believe that intermittent fasting produces longevity benefits and reduces disease risk without the adherence and biological challenges associated with chronic calorie restriction diets. Plus, fasting’s ability to help you resist disease is shown to be even more enhanced when combined with solid exercise habits!

#5. Intermittent Fasting Promotes Autophagy

Autophagy is an important, natural process in which your body clears older, tired, or worn-out cellular components so that your cells can function optimally. (Think of it as your body’s regular “clean-out.”) This process is critical to support metabolic health and anti-aging processes in your body’s cells, as well as immune-system function. Ultimately, if you want to improve your longevity, you should keep your cells’ autophagy capabilities in tip-top condition. Intermittent fasting helps you do this.

In humans, fasting for at least 18 hours can increase autophagy signals. In a 2019 study, overweight adults were split into two groups: one group fasted for 18 hours per day while the other group fasted for 12 hours per day for four days. The people who fasted for 18 hours per day saw their blood glucose levels and glycemic health metrics improve, their ketones increase, and the expression of their autophagy gene (LC3A) increase by 22%. In other words, by fasting 18 hours or more, you’ll enhance fat-burning, increase ketone production, and turn on autophagy genes — all desirable longevity benefits of intermittent fasting.

How Long Should You Fast for Longevity?

To determine how long you should fast for longevity, first consider your individual health, schedule, and preferences. Intermittent fasting is not for everyone, but if you’re motivated to experience its potential benefits, consider starting with shorter fasts to develop the skills, habits, and routines required to be successful. Generally, if you’re a healthy adult who is not pregnant, breastfeeding, or underweight, fasting for 12 hours every day is a good baseline to establish. Many longevity benefits are accrued over time, so the fasting practice that you can keep consistent is the one that will yield the most long-term benefit. (One intermittent-fasting experience is not going to be enough to dramatically improve your longevity metrics, like blood pressure or risk for cardiovascular disease!) 

Does Intermittent Fasting Reverse Aging?

Increasingly, scientific advances demonstrate that aging is a modifiable process. Although your chronological age progression is non-negotiable, researchers continue to find that biological aging can be slowed or even reversed through your lifestyle and habits. In fact, a clinical trial from 2021 demonstrated that specific lifestyle modifications — including mild intermittent fasting in combination with healthy nutrition, movement, sleep, and stress-management habits (the Four Pillars!) were able to reduce biological age by 3.23 years.

Can You Do Intermittent Fasting for Longevity Every Day?

Yes, you can do intermittent fasting for longevity every day. Research suggests that daily intermittent-fasting practices and longer-duration periodic fasting are safe strategies to improve your healthspan and lifespan. Some people enjoy the benefits of intermittent fasting enough that they make it part of their daily routine. If you decide to fast every day, it is important to prioritize diet quality. Compared to the average 14–15-hour eating window most people follow, you might only have about half that time to consume all your nutrients if you are practicing intermittent fasting for longevity.

What Does the Science Say About Intermittent Fasting and Longevity?

As discussed, the science demonstrates a clear connection between intermittent fasting and longevity. By intermittent fasting, you’ll be able to maintain a healthy body weight, which helps ward off chronic diseases. You’ll also reduce oxidative stress and inflammation, both of which are the top causes for the aging process. Finally, you’ll gain protection from many of the age-related chronic diseases (like diabetes and cardiovascular disease) that reduce quality and length of life for adults worldwide.

Of course, intermittent fasting for longevity is best paired with other longevity-boosting habits and strategies. Regular physical activity, healthy sleep, and consistent restorative practices all help to optimize the longevity benefits of intermittent fasting. Start by building an intermittent-fasting foundation upon which you can construct a well-rounded longevity lifestyle. 

Getting Started with Intermittent Fasting for Longevity

Intermittent fasting and longevity are closely intertwined. If you are interested in developing an intermittent-fasting practice, regardless of duration or type, Zero — the top-rated intermittent-fasting app — will help you track your fasts, learn how they’re affecting your body in real-time, and benefit from a community of like-minded people building habits that promote metabolic health and longevity.

Ready to start using Zero? Take the quiz or download the app today.

Rich LaFountain, PhD
Posted in Health & Science

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