Intermittent Fasting (IF)

Historically, humans have gone through periodic cycles of intermittent fasting (also called dietary cycling) and concomitant nutritional ketosis.

Intermittent fasting (IF) can be defined as consuming regular meals on some days and dramatically cutting calories on others. IF can have a number of health benefits, including improved cardiovascular health, reduced cancer risk, gene repair, weight loss and longevity.

This cyclical pattern of eating mimics the habits of our ancestors, who did not have consistent access to food.

Some studies show that dietary cycling produces a number of biochemical benefits,  dramatically altering how the body functions.

Some health benefits from intermittent fasting can include:

  1. Normalizing insulin and leptin sensitivity, which helps to regulate sugar metabolism, fat storage and appetite.
  2. Boosting mitochondria (the cellular powerhouse).
  3. Reseting the body to use fat as its primary fuel (fat adaptation). This state of nutritional ketosis, or fat adaptation, can dramatically reduce your risk of developing a number of  diseases.
  4. Normalizing ghrelin levels (ghrelin is the “hunger hormone”).
  5. Promoting human growth hormone (HGH) production. HGH has important implications in health, fitness, and slowing the aging process. It is also a fat-burning hormone.
  6. Lowering triglyceride levels and improving other biomarkers of cardiovascular diseases.
  7. Promoting anti-aging by optimizing insulin sensitivity and inhibiting the mTOR pathway, which plays an important part in driving the aging process. In addition, IF reduces oxidative stress by decreasing the accumulation of oxidative radicals in the cell, thereby preventing oxidative damage associated with aging and disease.
  8. Reducing sugar cravings. When sugar is no longer needed as a primary fuel, cravings are fewer.
  9. Helping to prevent and even treat dementia, Alzheimer’s and Parkinson’s. IF boosts the production of a protein called brain-derived neurotrophic factor, which activates brain stem cells to convert into new neurons, and triggers numerous other chemicals that promote neural health.

There are a number of IF strategies. In general, it involves cutting calories in whole or in part. This can be done a couple of days a week or even every other day, according to Dr. Mosley, who wrote a book on the subject, called The Fast Diet.

Mosley suggests 5 days of your normal calorie consumption and then fasting for two. This schedule is sometimes referred to as the “5:2”. On fasting days, he recommends cutting your food down to one-fourth of your normal daily calories, or about 600 calories for men and about 500 for women, along with plenty of water and tea.

Closing comments: IF is not for everyone. While certain health benefits have been shown, some people would not be ideal candidates (e.g. athletes, individuals with diabetes or hypoglycemia, people in physically active jobs, and those who are malnourished or underweight). IF should be undertaken with the guidance of a physician to ensure that nutritional needs are met.


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Christopher Hine, Eylul Harputlugil, Yue Zhang, Christoph Ruckenstuhl, Byung Cheon Lee, Lear Brace, Alban Longchamp, Jose H. Treviño-Villarreal, Pedro Mejia, C. Keith Ozaki, Rui Wang, Vadim N. Gladyshev, Frank Madeo, William B. Mair, James R. Mitchell. Endogenous Hydrogen Sulfide Production Is Essential for Dietary Restriction Benefits. Cell, 2014; DOI:10.1016/j.cell.2014.11.048

Vasconcelos, Andrea R.; Yshii, Lidia M.; Viel, Tania A.; Buck, Hudson S.; Mattson, Mark P.; Scavone, Cristoforo; Kawamoto, Elisa M.  Intermittent fasting attenuates lipopolysaccharide induced neuroinflammation and memory impairment. Journal of Neuroinflammation. 2014, Vol. 11 Issue 1, p1-28. 28p. DOI: 10.1186/1742-2094-11-85.


About the Author

Dr. Geoff LecovinNaturopathic Physician/Chiropractor/Acupuncturist/Certified Strength and Conditioning Specialist/Corrective Exercise Specialist/Performance Enhancement Specialist/Certified Sports Nutritionist/View all posts by Dr. Geoff Lecovin