Latest posts by Jessica Peatross, MD (see all)
Recently I finished a 50 hour water fast and had such splendid results that I decide to share it with you guys. So what is all the hype over fasting? Some scientific studies refute it and others seem to promote all various types of fasting requiring differing time lengths or instructions. So what’s correct? Unfortunately there haven’t been a ton of human studies on the benefits or risks of fasting. There have been plenty of animal studies however.
Most of the people promoting fasting are in a community of bodybuilders, fitness gurus, religious traditions, nutrition experts and bloggers. Traditional religious texts around the world have heralded fasting as a way to come to a higher power within themselves or even greater than themselves. Jesus was supposedly tempted while fasting 40 days and 40 nights in the wilderness. Not only Jesus, but the yogis of India, Buddha and the prophet Muhammad all shared a common belief in the healing power of fasting. In spiritual terms, it is considered cleansing or purificatory. Is there any correlation between temptation and fasting? Many ancient books seem to elude to this by suggesting fasting during times of turmoil. I actually had some emotional releases as well during my fasting period that was quite unexpected.
Mainstream medicine has not offered up many human trials on fasting and evidence is scant other than a large body of evidence in animals that DOES support fasting. I will personally tell you that the first 24 hours are a killer. Try not to be in a crowded, quiet place as your stomach will be growling!
What benefits in studies do support intermittent fasting? Fasting has been shown to have great promise by improving biomarkers of disease, reducing oxidative stress and preserving learning and memory functioning. Mark Mattson is a senior investigator for the National Institute on Aging (part of the US National Institutes of Health), who has researched the health benefits of intermittent fasting on the cardiovascular system and brain in rodents, and has called for “well-controlled human studies” in people “across a range of body mass indexes” (J Nutr Biochem 2005;16:129–37). Science still does not agree.
So the debate rages. I am happy to share the science based evidence that does exist with you, as well elaborate on my own personal experience.
1. LOSE WEIGHT AND IMPROVE INSULIN SENSITIVITY:
There have been a few human studies on this subject with conflicting evidence. In one study I read, Freehand and his researchers had mice fast twice a week for 24 hours each time. During their non fasting days, they were permitted to eat as much and whatever they wanted. The mice often overate. Therefore, the researchers concluded that there was no overall weight loss or added benefit due to the the fact that the mice overate and counteracted the fasting.
In my humble opinion, you cannot intermittently fast and then make up for it by gorging yourself with junk. I suspect that the researchers may have seen a different outcome had they fed the mice healthy and restricted meals on their non fasting days. More research is definitely needed but the results from Mattson’s team is quite promising.
How about increasing insulin sensitivity to lower blood sugars? We all know that caloric restriction leads to weight loss and weight loss leads to improving blood sugars in diabetics. So Mattson again tested out intermittent fasting but this time against continuous caloric restriction. He looked at bio-markers for different cancers, diabetes, and cardiovascular disease among young but overweight women. (1) They found that intermittent restriction was as effective as continuous restriction for improving weight loss, insulin sensitivity and other health biomarkers.
I would love to know what those women ate on their non fasting days. I know that my blood sugar stayed mostly stable throughout my 50 hour water fast. I actually did not feel the need to completely gorge myself after the fast ended either.
2. REDUCES OXIDATIVE STRESS AND ENCOURAGES CELLULAR REPAIR:
Oxidative stress happens every day to every human. We encounter rogue pathogens, toxic environmental agents, and heavy metals. Overexposure to any of these can damage DNA and produce free radicals. Free radicals are not necessary bad. In fact, nitric oxide is a free radical. It is when the antioxidants and free radical balance is askew that there are problems. Both are needed in certain variations and balances. When free radicals become excessive, the body has trouble removing waste and detoxification cannot occur. When we fast, the cells in the body are released from the duties of digestion and absorption, and can use energy to go towards removal of waste products. For example, cells have the ability to undergo “autophagy,” which is digesting themselves or other cells when they are mutated or old and considered waste. This involves the cells breaking down and metabolizing broken and dysfunctional proteins that build up inside cells over time. Fasting frees up energy for this process! This has been shown in studies to lend protection against several diseases like Alzheimers and some forms of cancer.
I will say that I felt extremely clear headed and sharp, but I did have a couple emotional releases. It makes sense and if you believe in as above, so below you will be able to understand this concept. Since my body was busy ridding itself of toxins no longer needed, my mind was also busy ridding itself of heavy emotions and old negative thinking patterns that no longer served me. This can be difficult because just as the body often needs to feel pain to realize there is a problem and correct it, the mind also needs to feel the pain of its past habits or beliefs to be able to change or release them. When you think about it, it may be a little easier to understand why the religious texts talk about physically fasting for mental or emotional strength.
3. NATURALLY RELEASES HUMAN GROWTH HORMONE AND INCREASES BRAIN FUNCTION:
Studies have shown that the blood levels of growth hormone sometimes increase up to five fold! I’m sure most of you have heard about growth hormone and the benefits it provides our bodies concerning anti aging. It has been shown to promote muscle gains, burn fat, and improve skin tightness. Human growth hormone or HGH, usually promotes the synthesis of lean muscle and the storage of glycogen as well as fat. “However, when fasting, increased levels of the hormone stimulate the breakdown of fatty tissue,” according to Niels Moller of Aarhus University Hospital in Denmark. “Your body needs the fat to produce energy. The increase in HGH during fasting helps to preserve your muscle tissue and glycogen stores while using your fat stores instead. This breakdown of fat, which is called lipolysis, releases free fatty acids and glycerol, which are then metabolized to produce energy. HGH begins to rise around the 13th hour of fasting.
There has been research on the protective benefits of fasting to neurons. If you don’t eat for 10–16 hours, your body will go to its fat stores for energy, and fatty acids called ketones will be released into the bloodstream. This has been shown to protect memory and learning functionality as well as slow disease processes in the brain.
The bottom line is that HGH is produced naturally in our bodies and is known as the “lean” hormone. It promotes weight loss and extra energy. Fasting also not only promotes health of the body, but the brain also.
4. CAN REGULATE GENE EXPRESSION TO PROMOTE LONGEVITY:
Studies like the one done in the journal Rejuvenation Research, show that the “stress” that fasting places on our bodies is an alert signal to the immune system to repair and hunt out any issues with detoxification. In Rejuvenation Research, Legman and his colleagues had participants alternate one day of eating 175% of their usual daily caloric intake with one day of eating 25% of their usual calorie intake. This went on over a 3 week period. Participants found fasting easier than feasting, and that on feasting days, they had some trouble keeping up their high caloric intake.
Over a 10 week interim, Wegman and his colleagues measured weight changes, heart rate, glucose levels, blood pressure, cholesterol, inflammatory markers and genes involved in protective cell responses, triggered by the stress response from fasting. Legman said, “We found that intermittent fasting caused a slight increase to SIRT3, a well-known gene that promotes longevity and is involved in protective cell responses.”
It is well established in the medical community that long term caloric restriction can induce gene expression for longevity. What this study shows is that it is easier to intermittently fast than it is to strict calories and this may produce the same protective genetic results. In one study, rats that fasted every other day lived 83% longer than the control.
5. SHOWS PROMISE IN WARDING OFF CANCER AND REDUCING THE EFFECTS OF CHEMOTHERAPY:
A recent study in 2009 proved that fasting can even reduce the severity of side effects of high-dose chemotherapy. Valter Longo, associate professor of gerontology and biology at USC and head of the study, explains it this way:
“In essence, these cells are waiting out the lean period, much like hibernating animals. But cancerous tumors respond differently to starvation; they do not stop growing, nor do they hibernate because their genetic pathways are stuck in an ‘on’ mode. Longo realized the starvation response might differentiate healthy cells from cancer cells by their increased stress resistance and that healthy cells might withstand much more chemotherapy than cancer cells.”
A few years later, Longo reported that fasting alone was enough to treat many types of cancer in mice. Because the body’s healthy cells were in this hibernation mode, the cancer cells tried to find other ways to divide and spread, without much success.
Another study entitled Fasting Enhances the Response of Glioma to Chemo- and Radiotherapy, also shows promise. In this study, the researchers attempt to increase our ability to kill mice glioma cells in the brain. These are the brain tumors that are resistant to modern day chemo and radiation plus difficult to resect in surgery. In the study, the effects of “starving” both cancer and normal brain cells was tested for 48 hours. However, those fasting mice were also subjected to chemo and radiotherapy. This could get pretty scary for some patients (and mice)!
What they found was that if the mouse, rat, and human glioma cells were treated with chemo-radiation DURING FASTING, it resulted in significant killing of the cancer cells. They also found a significant decrease in blood sugar and IGF-1 in these animals during the fast and suggested that this may have played a large role. Hint: High IGF is linked to cancer!
“An interesting twist to their findings is the fact that while fasting may sensitize the bad guys to treatment, it appears to spare our good cells from much of the toxicity of chemotherapy and radiation therapy. Other words, when they decreased the amount of available sugar available to cancer cells, cell death significantly occurred in these cells with no change in the normal cells exposed to chemotherapy. The fasted mice also experienced delayed tumor progression and lived significantly longer. Not a bad result from simply removing food for a couple days.” (4).
No wonder I felt so good on a 50 hour water fast! I actually can’t wait to do it again. Just to summarize one more time, here are the potential benefits from fasting:
- Fasting forces you to eat fewer meals, lowers your insulin levels, raises growth hormone levels, and increases your metabolic rate by between 3.6 – 14%, helping you burn more calories.
- Lowers the risk of type 2 diabetes – one study in diabetic rats showed it protects against kidney damage, one of the severe and common complications of the disease.
- Reduces oxidative stress and inflammation. Oxidative stress is one of the key players in aging and chronic diseases.
- Fasting increases a hormone called brain-derived neurotrophic factor. BDNF helps protect the brain.
- Releases human growth hormone, which promotes lean muscle mass and fat burning.
- Fasting may increase recognition and ability to destroy cancer cells, while lessening the effects of chemotherapy
- Personally fasting let me release harmful thought patterns, see the world through a new perspective (when he do something difficult, we may see outcomes and struggles in new light) and release harmful behaviors that have been haunting me for years! I released a lot emotionally; had outbursts and crying fits, but once they were over, i had shed years of past turmoil.
1. Int J Obesity 2011; 35: 714–27
2. The Protein-Retaining Effects of Growth Hormone During Fasting Involve Inhibition of Muscle Protein Breakdown www.diabetes.diabetesjournals.org/content/50/1/96
5. Free Radical Bio Med 2007; 42: 665–74