Does Intermittent Fasting Reduce Your Life Expectancy?

Does intermittent fasting reduce your life expectancy? This may seem like an odd question, considering that all the info you will find on a cursory online search points to an extended lifespan. So, why am I asking this question? Because a longevity expert that I respect claims it does. First, we will examine all the aspects of the claim that intermittent fasting reduces your life expectancy. Then, we will examine the evidence that intermittent fasting can help you live longer. We will also discuss some intermittent fasting guidelines for health and longevity.

Does Intermittent Fasting Reduce Your Life Expectancy?

Longevity expert, Professor Valter Longo claims that intermittent fasting does reduce your life expectancy, so I wanted to look into it. In this interview with Dhru Purohit, Dr. Longo explains that skipping breakfast increases your risk of obesity, diabetes, cardiovascular disease, and cancer. He also says that fasting for 16 hours doubles your risk of gallstones. Apparently, we don’t know why intermittent fasting poses these risks, possibly due to the increased presence of ketone bodies. He also claims that, ideally, you may choose to skip lunch or dinner and that breakfast should contain at least 400 calories.

Does Intermittent Fasting Reduce Your Life Expectancy: The Verdict

The short answer is no; intermittent fasting does not reduce your life expectancy.

I love Peter Attia’s balanced perspective on most topics, and he wrote a 2-part series entitled Does skipping breakfast increase the risk of an early death?, which turned out to be quite helpful in writing this blog post. The series is very exhaustive, and I recommend you check it out, but I will do my best to summarize it.

It critiques a study conducted by investigators from Texas Tech University (TTU) that claims regular breakfast consumption reduces the risk of all-cause and cancer mortality. The TTU study analyzed data from the National Health and Nutrition Examination Survey III (NHANES III) conducted between 1988 and 1994. The researchers relied on self-reported information from a single baseline questionnaire, where participants categorized their breakfast consumption into three groups: daily, some days, and rarely/never. The study was observational and not randomized.

Furthermore, breakfast skippers were almost a full decade older than breakfast eaters. Without any statistical adjustment, skipping breakfast is associated with a 32% reduction in all-cause mortality and an 8% reduction in cancer mortality compared to regularly consuming breakfast. At the time of follow-up, breakfast eaters were 72 and breakfast skippers, 82, on average. When adjusting for age alone, the associated risk was similar to when adjusting for age and other factors. This suggests that age might explain a significant portion of the observed associations between eating breakfast and better overall health outcomes.

The bottom line is: breakfast skippers are less health-conscious overall than breakfast eaters. The mainstream health advice is to NOT skip breakfast. Consequently, those who are health conscious will be more diligent about not skipping breakfast. I do remember Dr. Longo pointing out in the interview that even if that was the case, skipping breakfast should reduce the risks associated with other poor health habits, and in Peter Attia’s article, we see that adjusting for age does, in fact, give similar outcomes.

What About Gallstones?

Dr. Berg addresses the formation of gallstones, which is another intermittent fasting risk factor, according to Dr. Valter Longo. According to Dr. Berg, intermittent fasting does not cause gallstones and, when combined with the keto diet, can promote a healthy gallbladder. Additionally, adopting these dietary practices can lead to various benefits such as weight loss, increased energy, and improved mental clarity.

Intermittent and Periodic Fasting, Longevity and Disease

As it turns out, you will find studies to support whatever your beliefs are and that’s not just n the world of intermittent fasting. For example, here are some key points from this study on intermittent fasting and longevity:

  • Intermittent fasting involves cycling between periods of fasting and eating. The most common method is the 16:8 approach, where you fast for 16 hours and restrict your eating to an 8-hour window each day. Other variations include alternate-day fasting, where you fast every other day, and the 5:2 method, where you eat normally for five days and restrict calories for two non-consecutive days. During the fasting period, only water, unsweetened beverages, and calorie-free drinks are consumed.
  • Periodic fasting refers to longer fasting periods that extend beyond a typical daily fasting window. This can include fasting for 24 hours, 48 hours, or even several days at a time. Extended fasts may require medical supervision and should be approached with caution.
  • Studies conducted on animals and some preliminary research on humans suggest that intermittent and periodic fasting may promote longevity. Fasting triggers cellular and molecular mechanisms that enhance cellular repair, reduce inflammation, and improve metabolic health. These processes may contribute to slowing down the aging process and extending lifespan. However, more long-term human studies are needed to fully understand the effects of fasting on lifespan.
  • Intermittent and periodic fasting have been linked to a reduced risk of various chronic diseases. Some research suggests that fasting can improve insulin sensitivity, regulate blood sugar levels, and decrease inflammation, which are important factors in preventing conditions like type 2 diabetes and cardiovascular disease. Fasting has also shown potential benefits for weight management, as it can promote fat loss while preserving muscle mass.

In summary, intermittent and periodic fasting are dietary patterns that involve alternating periods of fasting and eating. These approaches have been associated with potential benefits for longevity and disease prevention, including improved metabolic health and reduced risk of chronic diseases. However, more research is needed to fully understand the long-term effects and individual variations in response to fasting.

How Long to Fast for Longevity

There is no definite answer, but 12 hours is often considered a good baseline (including by Dr. Valter Longo). For some, the best fasting method will be 12 hours a day.

My recommendation is to fast long enough to switch to optimal weight loss ketosis a few days a week. This will help ensure you remain metabolically flexible. I explain what that’s all about in my post Using Intermittent Fasting for Metabolic Flexibility. In short, optimal weight loss ketosis is producing enough ketones for fuel to feel energized while fasting. With experience, you will be able to tell as your hunger won’t be bothering you and you will be able to carry on your daily tasks until your next meal. For beginners, a ketone monitor may be helpful and you will discover that the “switch” to optimal weight loss ketosis often occurs at around 1.0 mmol/L. You may also want to read How to Keto Diet for Weight Loss and Health: Wait! It’s Not What You Think! for additional help.

Intermittent Fasting Benefits

Intermittent fasting has changed my life! So, yes, I find it hard to believe it could reduce your lifespan. I went from struggling with food cravings, being almost overweight (BMI of 24) and gaining weight, poor sleep, and low energy to being at my ideal weight and feeling energized and sleeping well—all that from discovering how to use the right intermittent fasting method for me. Learn more about How I Lost Weight After 40: My Success Story.

Here are some benefits you can enjoy:

  1. Weight Loss: Intermittent fasting can be an effective tool for weight loss. Restricting the eating window helps create a calorie deficit, leading to fat loss. Additionally, fasting may increase levels of human growth hormone (HGH), which can aid in preserving muscle mass while promoting fat burning.
  2. Improved Insulin Sensitivity: IF can enhance insulin sensitivity, allowing cells to more efficiently take up glucose from the bloodstream. This can help regulate blood sugar levels and reduce the risk of insulin resistance and type 2 diabetes.
  3. Reduced Inflammation: Fasting has been shown to decrease markers of inflammation in the body. Chronic inflammation is associated with various diseases, including cardiovascular disease, cancer, and neurodegenerative disorders. By reducing inflammation, intermittent fasting may contribute to improved overall health.
  4. Enhanced Cellular Repair: During fasting, the body initiates a process called autophagy, where old or damaged cells are broken down and recycled. This cellular repair mechanism may help remove toxins and dysfunctional components, potentially promoting longevity and reducing the risk of age-related diseases.
  5. Improved Brain Function: Some studies suggest that intermittent fasting may have cognitive benefits. It may enhance brain health by promoting the production of brain-derived neurotrophic factor (BDNF), a protein that plays a role in neuroplasticity and the growth of new neurons. This could potentially enhance memory, focus, and overall brain function.
  6. Heart Health: Intermittent fasting has been associated with improvements in heart health markers, including blood pressure, cholesterol levels, and triglyceride levels. By reducing these risk factors, IF may help protect against heart disease and promote cardiovascular well-being.
  7. Longevity: While more research is needed, some animal studies indicate that intermittent fasting could extend lifespan. Fasting activates cellular repair processes, reduces oxidative stress, and improves metabolic health, which are factors that may contribute to increased longevity. (Check out the article Can Intermittent Fasting Help You Live Longer?)

It’s important to note that individual responses to intermittent fasting can vary, and the specific benefits experienced may depend on factors such as overall diet quality, lifestyle factors, and individual health status (as we discussed when evaluating whether intermittent fasting could reduce your life expectancy).

Does Intermittent Fasting Reduce Your Life Expectancy Video

In Summary

Can intermittent fasting reduce your life expectancy? When accounting for confounding factors, it appears that intermittent fasting does not decrease your life expectancy. In fact, it will most likely increase your longevity and quality of life. However, like any decision concerning your health, I suggest you experiment for yourself and find what works for you.