The Curious Case of Intermittent Fasting
Intermittent fasting has gained popularity as recent studies shed light on its role on cellular adaptation, curbing inflammation, optimizing energy metabolism and boosting cellular protection. Research has shown that reducing typical calorie consumption, usually by 30 to 40 percent, extends life span by a third in animal studies.Intermittent fasting comes as a promising alternative to continuous calorie restriction, it’s appeal growing from not interrupting the pleasure of the feast. People don’t feel deprived anymore from the joy of food. Religious fasting has been practiced for millennia by Muslims during Ramadan, Christians, Jews, Buddhists or Hindus who traditionally fast on designated days of the week or calendar year.
Initially thought to benefit mainly the soul, the health benefits were recognized in early 1900 and recommended for various medical conditions. Emerging research is supporting the benefits in humans as well. Studies done in rodents showed that periodic fasting can protect against heart disease, cancer, diabetes, obesity, hypertension, neurodegenerative diseases like Parkison and Alzheimer, rheumatoid arthritis.
What Does it Mean:
By fasting and then feasting on purpose, intermittent fasting generally means that you consume your calories during a specific window of the day, and choose not to eat food for a larger window of time. During the fasting period, you consume no calories. However, black coffee, calorie-free sweeteners, diet soda and sugar-free gum are permitted.
How It Works:
When you eat a meal, your body spends a few hours processing that food, burning what it can from what you just consumed. During the fasting state the energy is taken from deposits and the fat burning hormones tend to go up. This is like exercising your hormonal balance, you maintaining a healthy two-way feedback loop, fat storage – fat burning versus one way toward fat deposits.
Another way through which fasting creates healthier habits is that it trains the will power muscle and helps people become more comfortable with the sensation of hunger. Better one can control hunger, less likely will succumb to it.
During fasting few things happen at cellular and molecular level.
- The most important benefit of fasting is increasing insulin sensitivity. That means that cells are able to metabolize better the carbohydrates and the doors to the fat deposits are open versus being lucked as in insulin resistance syndrome.
- It has been show that fasting can increase HGH as much as 5-fold. HGH is known for its burning fat, building muscle, improving skin texture.
- Improved cellular repair “autophagy”- Intermittent fasting allows cellular defense to rebuilt its reserves and interrupts the continued cellular stress that triggers inflammation. These rest periods allow the body to ramp up the waste removal process that otherwise would build up leading to Alzheimer and Parkinson’s disease. Autophagy has been recognized as the defense mechanism against neurodegenerative diseases.
- Increase metabolism through improving thermogenesis, browning of the white fat. White fat is known to be linked to obesity and diabetes.
- Improved cognitive ability, mood and delay Alzheimer disease, reduces anger, stress. No wonder fasting has been linked to spiritual traditions. Intermittent fasting increases proteins that nourishes the brain cells (brain-derived neurotrophic factor), stimulates neuron growth and sustains brain circuits.
- Positive effects in decreasing carcinogenesis and slowing tumor growth, augmenting chemotherapy benefits via Sirtuins pathways.
- Weight loss – long as one don’t compensate by eating much more during the non-fasting periods, then these methods will lead to reduced calorie intake and help one lose weight and belly fat.
- Improves the gut bacteria profile, as it gives microbes a break from their duties. Feeding/fasting cycles allows for a more diverse gut microbiome associated with a positive metabolic and immunologic profile. The fasting period allows the gut lining to heal and recover and improve its barrier function vital in filtering toxins and pathogens ingested.
- Modulates gene expression – called epigenetics, that genetic switch on/off that we can control through our behavior and awake genes related to longevity and protection against degenerative disease.
How to do it:
16 Hours Fasting/8 Hours Eating Method – simplest intermittent fasting protocol since part of the fasting time is during sleep and the best for beginners.
5:2 diet (called Fast Diet) – two nonconsecutive days have 500 calories, 5 days normal healthy food.
7:1 Eat Stop Eat – Consuming only non-caloric beverages for a full 24 hours 1-2 times per week.
1:1 Alternate Day Fasting – Becoming popular for a kick start weight loss is restrictive calories every other day, at about 25%. Regarding the weight loss benefits, the jury is out on the verdict as it didn’t prove to be more effective than restricted calorie diet. It is least sustainable of all fasting methods in long term and is associated with more over eating in the non fasting days.
My favorite and easiest to implement is the 16:8, as you only have to work with 8 hours and the other 8 you sleep. It is more sustainable and easy to stick to. Also I find it more physiologically as our body has its own clock called circadian rhythm, and hormones levels are made to process food more during day time versus night time. Easy to alternate with the two days/week 500 calories days, in case that your were not able to keep the schedule 16/8.
When examining the rate of weight loss, people lost about 0.55 pounds (0.25 kg) per week with intermittent fasting, but 1.65 pounds (0.75 kg) per week with alternate-day fasting.
However studies comparing intermittent fasting and continuous calorie restriction show no difference in weight loss if calories are matched between groups.
Thus, fasting can potentially delay aging and can hamper diseases while minimizing the struggles of intense dietary interventions. That being said, doesn’t mean that during feasting hours you can just can gulp on French fries and chips. Fasting at night is ideal as eating food at night can impair the melatonin production and affect the sleep quality. Avoid fasting during day time in the 16:8 schedule.
- Intermittent fasting vs daily calorie restriction for type 2 diabetes prevention: a review of human findings
- Augmented growth hormone (GH) secretory burst frequency and amplitude mediate enhanced GH secretion during a two-day fast in normal men.
- Effects of human growth hormone in men over 60 years old
- Fasting enhances growth hormone secretion and amplifies the complex rhythms of growth hormone secretion in man
- Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism
- Mitochondrial degradation by autophagy (mitophagy) in GFP-LC3 transgenic hepatocytes during nutrient deprivation.
- Short-term fasting induces profound neuronal autophagy