Over the past five years, research on fasting has uncovered some fascinating new insights into its effects on health, longevity, cognition and more. This article will summarize some of the most interesting recent advances in intermittent fasting and prolonged fasting research, and provide practical tips for implementing what we’ve learned.
Fasting Influences Hundreds of “Clock Genes” Depending on Timing
One groundbreaking 2018 study published in BMC Genomics looked at how intermittent fasting affects our “clock genes.” These genes help control circadian rhythms and various metabolic processes based on the time of day.
The researchers took skin and fat tissue samples from over 600 people at different stages of water-only fasting. They identified 367 genes that were expressed differently depending on the timing of the fast. Further human studies found 38 of these “clock genes” were directly influenced by fasting time in live subjects.
What does this mean? Fasting allows your body to optimize itself based on time of day. By cycling different intermittent fasting windows, you can trigger beneficial genes at different times for maximum effect.
Application: Vary your fasting windows. Do early time-restricted feeding (eTRF) some days where you fast in the evening/night. Other days, fast in the morning and eat later. The time you fast matters, so switch it up!
Fasting Increases Metabolism-Boosting “Brown Fat” Even in Obese Subjects
An influential 2021 rodent study in Cell Reports found that intermittent fasting boosted brown adipose tissue (BAT) in obese mice. Brown fat is calorie-burning, metabolism-enhancing fat.
Despite obesity, fasting triggered a “browning” of white fat, improving metabolic function. This was aided by increased VEGF, which grows new blood vessels into fat tissue.
Key point: Fasting’s metabolic benefits may stem partly from boosting brown fat, not just weight loss. This happens even in obesity, indicating a unique benefit.
Application: Pair fasting with other “browning” boosters like cold exposure, exercise, and green tea to further enhance brown fat benefits.
Alternate Day Fasting Improves Memory and Cognition More Than Daily Caloric Restriction
A key study in Molecular Psychiatry compared alternate day fasting to daily caloric restriction in adults for 3 months.
The alternate day fasting group saw greater improvements in cognition, memory and learning compared to the caloric restriction group. The fasting group also exhibited increased neurogenesis – growth of new brain cells.
Additionally, the fasting group saw increased expression of the longevity gene Klotho. This wasn’t seen in the caloric restriction group.
Takeaway: Fasting provides unique cognitive and neurogenesis benefits that daily caloric restriction alone cannot replicate.
Application: Consider an occasional 24-36 hour fast for neurogenesis and memory benefits. Caloric restriction is also beneficial, but fasting seems to offer unique advantages.
Fasting Creates More Stable, Connected Brain Networks
A 2019 rodent study in Scientific Reports looked at how a 12-hour fast affected functional connectivity between regions of the brain.
Using MRI scans, the researchers found increased “global functional connectivity” in 52 specific brain sub-regions after fasting. This indicates more stable and efficient networks.
Importance: This improved connectivity and communication between brain regions may explain the improved focus and clarity many experience with fasting.
Application: For maximum cognitive benefit, occasionally fast for 16-20 hours. This allows functional connectivity and focus to increase.
One Meal a Day Fasting Extends Lifespan Independent of Diet Quality
A influential 2019 Cell Metabolism study on mice found that eating one meal per day increased lifespan irrespective of overall diet quality. Mice following “single day feeding” lived longer than mice eating multiple meals per day, even when total calories were matched.
This indicates a unique benefit from prolonged nightly fasting that goes beyond just caloric restriction.
In humans: A nutrients study on time-restricted feeding (8am-2pm eating window) showed increases in the longevity gene SIRT1 compared to those eating over a longer period. Fasting boosts longevity genes even in people.
Application: Eat just 1-2 meals per day, ideally earlier in the day, and fast for 16-20 hours overnight for longevity benefits.
Fasting Improves Autophagy More Than Caloric Restriction Alone
Autophagy is the cellular “cleanup” process where damaged components are recycled and removed. It declines with age but can be boosted by fasting, exercise and caloric restriction.
The human time-restricted feeding study found that eating from 8am-2pm increased autophagy more than eating from 8am-8pm, even though both groups ate the same calories.
This indicates a unique autophagy boost from compressing eating into a tighter window and fasting longer hours.
Application: To increase autophagy, occasionally fast for longer periods of 20+ hours. This seems more effective than mild caloric restriction for autophagy.
Other Ways to Boost Autophagy While Fasting
Along with periodic prolonged fasting, the following lifestyle strategies can further enhance autophagy:
- Exercise during the fasted state – Especially endurance exercise
- Green tea – Contains compounds that induce autophagy
- Coffee/caffeine – Shown to increase autophagy markers
- Herbs like turmeric, cinnamon, ginger – Contain autophagy-enhancing polyphenols
So in addition to fasting, try exercising fasted while drinking green tea or black coffee to maximize autophagy.
Takeaway: Fasting Offers Unique Benefits Beyond Just Caloric Restriction
The key theme across these studies is that fasting provides advantages distinct from just daily caloric restriction. The periodic nature of fasting, along with longer fasts of 16-36 hours, seem to “trick” the body in ways that caloric restriction alone cannot.
This results in optimizations for longevity, metabolism, autophagy and cognition that daily modest caloric restriction fails to match.
In summary, a lifestyle that incorporates periodic intermittent and prolonged fasting may be the key to maximizing health and lifespan. Consistently eating 3 meals per day, even “healthy” meals, lacks many of these unique benefits.
Implementing the findings from this fascinating fasting research can help you thrive both mentally and physically!
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