Intermittent fasting is simply consuming your normal meals within a restricted time period each day, with no need to eat any less than you normally would do.
This gives the body more rest from digesting food, which results in benefits such as:
- Burning more stored fat as fuel
- Reducing visceral fat (fat surrounding organs)
- Substantially reduced fasting insulin levels
- Improve in circulating lipid levels
- Increased leptin sensitivity (reducing the risk of chronic disease)
- Increased ghrelin levels (reducing the risk of over-eating)
- Decreased triglyceride levels (lowering risk of heart disease)
- Decreased inflammation and free radical damage
- Protect memory and learning functionality (as a result of increased ketones released into the bloodstream)
- Promotes cellular regeneration
- Improve mood and self-confidence, reduce anger, fatigue, tension
The western diet typically includes eating from around 8am, continuing to around 10pm. This is 16 hours of eating and 8 hours of fasting.
Intermittent fasting flips these numbers around - by starting to eat at 12 noon and finishing eating at 8pm, we eat for 8 hours and have 16 hours of fasting.
Going even further, one can stop eating at 6pm, for even more fasting - 6 hours of eating and 18 hours of fasting.
The comparison of the typical western diet and 16:8 and 18:6 intermittent fasting diets is illustrated below:
The hours can be different - for example starting to eat at 8am and finishing at 4pm is an alternative.
“Fasting” can mean no food or liquid, or liquids only, it is down to personal preference. I generally restrict eating and drinking to between 6 and 8 hours per day, and don’t eat or drink outside of this period. It has dramatically improved my digestion.
This kind of adjustment is meant as a lifestyle change rather than a fad diet.
Of course, humans are not mice, so this study is for reference only, but mice with the longest fasting period seemed to have a longer lifespan and better outcomes for common age-related liver disease and metabolic disorders.
While the researchers do not fully understand why fasting is associated with longevity, they hypothesize that “extended daily fasting period enables repair and maintenance mechanisms that would be absent in a continuous exposure to food.”