Medical experts warn against the practice of extended periods of fasting for weight loss. It is not effective and can lead to slowed metabolism and muscle loss. ‘Intermittent Fasting’ on the other hand is getting a huge renewed interest from many health authors including Dr. John Belardi and Timothy Ferriss of “The Four Hour Body” fame. Intermittent fasting is nothing new. Humans have fasted all through history, due to food scarcity, or for religious reasons.
Fasting refers to the abstinence from food for 16 hours or longer, and it is continuously practiced over a certain number of days or weeks. There are many opinions on what qualifies as fasting. Some abstain from solid foods, allowing fruit juices and water, others insist that they should not eat or drink anything for several days in a row.
Benefits of brief Intermittent Fasting (16-48 hours) may include:
* Reduced blood lipids
* Reduced blood pressure
* Reduced markers of inflammation
* Reduced oxidative stress risk of cancer
* Increased cellular repair and growth hormone release
* Increased fat burning and blood sugar control
Potential dangers of long term ‘water only’ fasting for more than 48 hours at a time:
* Increases Stress Hormone Release
* Damages and Reduces Muscles
* Leads to Increased Hunger
* Health Problems i.e. Osteoporosis caused by lack of critical nutrients.
DO NOT DO EXTENDED FASTING WITHOUT THE ASSISTANCE
OF A QUALIFIED HEALTH PRACTITIONER.
Safest Fast: Finish eating by 6 pm. Eat breakfast at 10 am the next day. This totals 16 hours without food but many experience minimal exhaustion or hunger pains.
If you consume green vegetable juices or herbal teas, an amino acid supplement in the fasting window it is considered Calorie Restriction (CR). This is not the same as IF and does not have the same effects.
Two well-known health authors/blogger that recommend short fasts:
1. Tim Ferriss author of The Four Hour Body, is big advocate of Intermittent Fasting in his blog, “Real Life Extension: Caloric Restriction or Intermittent Fasting? (Part 1) (Part 2)”. He has also featured guest such as Dr. Ronda Patrick (American biochemist and scientist) who has done extensive research on IF and the benefits to the body. If you want to geek out on the science of IF, listen to Patrick’s interview on the Tim Ferriss podcast.
Tim is also known for repairing the damage he experienced from Lyme's Disease with a 5 day, medically supervised, fast.
2. Dr. Michael Eades MD author of The Protein Power Lifeplan, recommends 24-hour fasts that starts with a food cutoff time of 6 PM and fasting continues until 6 PM the next day. He suggests breaking the fast with a light protein rich supper right after 6 PM. This assures that you don't have to go a whole day without food.
It is important to avoid long fasts (unless for medical reasons). The biggest one on the market today is the 1976 classic book The Master Cleanse AKA The Lemonade Detox Diet by Stanley Burroughs. The diet is essentially a ten day fast, with pre-determined drinks, primarily lemonade. The Master Cleanse requires drinking about a quart of salt water every day and laxative mixtures at night. This could be worse for your body than a regular fast or juice fast because flushing your digestive tract so radically and rapidly you will flush important electrolytes. The loss of vitamins and critical minerals is compounded by the nightly laxative concoction.
There are many problems with this fasting model that I have experienced personally. After following the protocol to the letter for 12 days, I experienced stomach upset, reduced beneficial bacteria in my digestive system leading to diarrhea, mouth ulcers and wild swings in blood sugar and moods.
Here are the 4 big reasons to avoid long fasts of longer than 48 hours:
1. Fasting Can Increase Stress Hormone Release: When you are fasting, your body will go into a self-preservation mode to counter starvation. It will begin to slow down your metabolism and increase the production of cortisol. Cortisol is a stress hormone that is produced by the adrenal glands. When you are suffering from illness or stress, there will be a larger than usual amount of cortisol in your body. A high amount of cortisol can make you feel physically, mentally or emotionally stressed.
2. Fasting Damages Your Muscles: When you are not taking enough food, the cortisol in your body will try to release certain amino acids from your muscles and convert them to sugar. The sugar will then be fed to the brain, kidneys and red blood cells. The brain can use fats or sugar as fuel, but it usually prefers sugar, and red blood cells need sugar to survive. By releasing amino acids, cortisol is actually breaking down your muscle tissues. Losing muscles can slow down weight loss, because you need muscles to burn excess fat in your body.
3. Fasting Leads to Increased Hunger: If you do not consume food for a prolonged period of time, your body will produce fewer thyroid hormones. The loss of thyroid hormones and muscle tissue breakdown will slow down your body's overall metabolism significantly. This consequence becomes evident when you stop fasting and resume normal eating habits. When you begin to fast, your appetite hormones will be suppressed, but they will go into full gear when normal eating resumes, resulting in increased hunger. With slower metabolism and increased appetite, you will begin to gain weight fast.
4. Fasting Causes Health Problems: Prolonged fasting can deplete the supply of essential nutrients in your body, such as carbohydrates, proteins, vitamins, fatty acids, minerals and electrolytes. This can lead to the development of various health problems, including fatigue, headache, dehydration, dizziness, constipation, hypoglycemia, anemia, muscle weakness, gallstones and mental confusion. If you are suffering from some kind of health problem, it is advisable that you do not fast, because you will become more susceptible to the detrimental effects of fasting.
What are the benefits of short-term Intermittent Fasting?
The best review on the Internet would have to come from Mark Sisson authour of The Primal Connection.
Here is a short summery:
"Longevity: One study (full PDF) from the 1940s found that varying amounts of twenty-four hour IFs prolonged the lifespan of rats. Reductions in brain insulin signaling have been shown to increase lifespan in animals, either by calorie restricting or actively knocking out brain insulin receptors. Fasting also reduces brain insulin signaling, at least in rats.
Blood Lipids: IF is as or more effective than calorie restriction in improving metabolic syndrome markers in overweight women, and it’s a whole lot easier to stick with. Alternate day fasting improved cardiovascular risk markers, including lowered triglycerides and LDL-C numbers (although it’s unclear whether the improvements were related to the weight loss alone or something unique to fasting).
Reduction in Cancer: Some researchers are speculating, based on substantial evidence, that fasting before and during cancer treatment should result in reduced morbidity, better tolerance of chemotherapies, and higher cure rates. A preliminary study in human cancer patients found that fasting during chemotherapy reduced the negative side effects of the treatment.
Growth Hormone: Aging humans “normally” experience reductions in growth hormone. Luckily, short-term fasting induces growth hormone secretion in “normal men.” I’m not for mainlining GH or anything, but I’m all for amping up my own production.”
Here is some more on that topic from the BBC:
“The IGF-1 hormone (insulin-like growth factor) is one of the drivers, which keep our bodies in go-go mode, with cells driven to reproduce. This is fine when you are growing, but not so good later in life. There is now evidence suggesting that IGF-1 levels can be lowered by what you eat. Studies on calorie restrictors suggest that eating less helps, but it is not enough. As well as cutting calories you have to cut your protein intake. Not entirely - that would be a very bad idea. It's about sticking to recommended guidelines, something most of us fail to do. The reason seems to be that when our bodies no longer have access to food they switch from "growth mode" to "repair mode". As levels of the IGF-1 hormone drop, a number of repair genes appear to get switched on according to ongoing research by Professor Valter Longo of the University of Southern California.” Click here to read more.
Back to Mark Sisson:
“Neurological Health: Any dietary restriction tends to increase neuronal plasticity and promote neurogenesis, but it was IF that had the greatest effect (with the fewest downsides). Another study found that IF was beneficial for peripheral nerve function in mice by promoting the maintenance of the neuronal pathways responsible for locomotor performance.
Autophagy: Fasting turns on autophagy (most studies nowadays treat this as common knowledge), which is the process by which cells recycle waste material, eliminate or down regulate wasteful processes, and repair themselves. It’s required to maintain muscle mass, and inhibiting it induces atrophy of adult skeletal muscle. It reduces the negative effects of aging and reduces the incidence and progression of aging-related diseases. Short term fasting, too. No marathon thirty-six hour fast required.
Fitness: You’ll hear that you should never exercise on an empty stomach. Fasted training can actually result in better metabolic adaptations (which mean better performance down the line), improved muscle protein synthesis, and a higher anabolic response to post-workout feeding (you’ll earn your meal and make more muscle out of it if you train on an empty stomach).” Click here to read more.
A doctor who wrote an interesting ebook on Intermittent Fasting is Dr. John M Berardi.
Fasting is a medically accepted and proven way to detox your body from pollutants and the ingestion of harmful elements such as mercury from fish, lead and chlorine from tap water, and artificial sweeteners and other chemicals used to process and preserve foods.
I can attest to the fact that monitored detoxifying food cleanses that run 600 calories a day that include 10 servings of vegetables and seed protein choices like flax and hemp, (made into smoothies, salads and soup) may be the easiest and most sustainable way to cleanse your body. The long-term benefits I have encountered in my 17 years of nutritional practice include a reduction of pain; increased energy and a new found ability to tune into intuition of what is a healthy food choice.