Chronic starvation, or long-term suboptimal nutrition, weakens the body. But occasional starvation is good for you. It stimulates the body’s biological response system. Over time, even if one nutrient is missing or in short supply—like protein, carbohydrates, calcium, zinc, or iron—your body cannot function properly. On the other hand, if you provide abundant nutrition rich in all elements, and practice regular fasting (voluntary short-term starvation), you can prevent disease, promote health, and foster longevity.
Fasting: An Overview
Since fasting involves cutting calories, but only on fast days, it brings about biochemical and physiological changes that daily dieting does not. Calorie restriction (CR) has its benefits, but chronic calorie restriction can increase susceptibility to infections and has other biological consequences.
The foundation of all natural therapies and self-healing programs is fasting. The first step in rejuvenating your body and preventing disease begins with depriving the body of food for short periods of time so it can detoxify and cleanse. The most basic detoxification or cleansing program is fasting. This powerful, yet potentially dangerous, method of restoring your body’s function requires time and stamina. It is not for the very ill, elderly, or for busy stressed people.
A Brief History of Therapeutic Fasting in America
Fasting has a long history. In the West, it dates back to Hippocrates, the “father” of western medicine. In 1908, Linda Hazzard, an American nurse, published a book called Fasting for the Cure of Disease, which claimed that restricting food was the route to recovery from a variety of illnesses including cancer. Hazzard was jailed after one of her patients died of starvation.
Dr. Benedict Lust (1872 – 1945), considered the father of American naturopathy, believed in the inherent ability of the body to heal itself, and was an advocate of water cures and fasting.
My nature cure mentor, Dr. Bernard Jensen (1908 – 2001), advocated raw foods and juicing, colon cleansing, and fasting at his Hidden Valley health ranch in the hills outside of Escondido, California. Many fasting retreats and medical centers offering detox programs have sprung up in recent years. Founded in 1978, the International Association of Hygienic Physicians (IAHP) is a professional association for physicians who specialize in therapeutic fasting.
Evolution and Fasting
It seems that we are evolutionarily wired to go without food intermittently. Indigenous people do not eat three meals a day plus snacks, plus health food store super foods, nor do they take supplements. Of course, their food supply comes direct from wild nature with much higher nutritional density than modern farmed foods. Our genes seem to be geared to not only being able to cope with periods of no food, but to thrive.
Fasting aligns us biologically with our evolutionary history. Over the 250,000 years that Homo sapiens have been around on the planet, the food supply was variable. Our bodies evolved to take advantage of this fact, building muscle and fatty tissue during times of abundance, and then paring it back during lean ones.
When I lived with the Siberian Yupik people, periodic starvation was common. When there was food, we ate a lot. When hunting was poor and there was no food, we starved. The Q’ero of the Peruvian Andes, who I’ve worked with and lived among since 2000, eat large amounts of carbohydrates, mostly potatoes, but can endure days with little to no food. But, when they have access to food, they will eat twice as much as normal. When the food supply is abundant again, they eat regular meals two or three times daily.
This practice of feast or famine gives an idea that in our society of abundant food, we should eat moderately and regularly, provide optimal nutrition, and practice intermittent fasting, mimicking periodic famine as experienced by our ancestors.
What Science Tells Us About Fasting
Research on fasting suggests that it helps people with cancer and reduces the risk of developing cancer, guards against diabetes and heart disease, helps control asthma, and wards off Parkinson’s disease and dementia of the elderly. Of course, fasting helps people attain normal weight.
Valter Longo, director of the Longevity Institute at the University of Southern California, thinks that short-term complete fasts maximize the benefits of chemotherapy. He found that a 48-hour total fast slowed the growth of five of eight types of cancer in mice, the benefit tending to be more pronounced the more fasts the animals endured. It appears that fasting is harder on cancer cells than on normal cells. That’s because the mutations that cause cancer lead to rapid growth, but they don’t do as well when they are deprived of calories.
Fasting lowers insulin growth factor 1 (IGF-1). High IGF-1, as well as insulin and glucose, increase your risk for cancer, and make it harder to beat when you have cancer. Low levels of IGF-1 are associated with a decreased risk of cancer and increased lifespan. Five days without food can reduce IGF-1 by 70 per cent. IGF-1 levels in strict vegans are also significantly lower that those eating the standard American diet.
Fasting also raises human growth hormone (HGH). A 24-hour water-only fast once a month raises levels of HGH, which triggers the breakdown of fat for energy use, reducing insulin and glucose levels. Not only does fasting lower insulin, it improves insulin sensitivity—the ability of cells to more effectively utilize insulin helping the body sustain healthy metabolism.
Fasting is a mild stressor, as well, which enhances brain activity. Alternate-day modified fasting, with a single meal of about 600 calories on the fast day, can boost the production of a protein called “brain-derived neurotrophic factor (BDNF)” by 50 to 400 per cent! BDNF is a member of the nerve growth factor family and is involved in the generation of new brain cells. It also plays a role in learning and memory, and can protect brain cells from the changes associated with Alzheimer’s and Parkinson’s.
What Happens When You Fast?
An overnight fast of 8 to10 hours is normal for most people. A fast is considered to start 10 to 12 hours after your last meal, which is when you have used up all the available glucose in your blood and start converting glycogen stored in liver and muscle cells into glucose to use for energy.
If the fast continues, there is a gradual metabolic shift towards breaking down stored body fat to use as energy. The liver produces more ketones—short molecules that are by-products of the breakdown of fatty acids. The brain can use ketones as fuel in the absence of glucose. This process is in full swing three to four days into a fast.
During a fast, you loose weight. You blood pressure goes down. Fatty acids are depleted. Thyroxin and some other hormones trend lower. Short fasts of few days leave mineral levels like sodium, potassium, and calcium stable. Some studies show that zinc levels go up.
Fasting accelerates the cleansing of waste products left by dead and damaged cells, a process known as autophagy. A failure of autophagy to keep up with accumulated cellular waste is believed by many scientists to be one of the major causes of the chronic diseases associated with aging.
The basic premise of intermittent fasting (IF) is to enjoy better health by repeatedly fasting for longer periods than is typical on a daily breakfast-lunch-dinner schedule. IF means abstaining from solid food, but allows hydration with water, herbal or green tea, or other low-calorie beverages like green vegetable juices.
Different regimens have different effects on the body. Variations are endless. Some proponents skip breakfast; others, dinner. Others fast all day every other day, every third day, once a week, or one to three days per month. Some fast for a week or ten days, or longer, annually.
I recommend a fasting or modified fasting day each week, or three days every month. In addition, I advise patients to do a 10-day cleansing program once or twice every year. Younger, robust individuals can fast only on water. Busy, stressed people, older folks, and those with health conditions should start with modified CR plans. Total fasting can pose greater challenges then their bodies can handle.
Dangers of Fasting
Children under 18, diabetics, and pregnant or lactating women should not fast. Frail elderly people should not either, but could benefit from partial fasts and limited CR. Insulin dependent diabetics or those with cardiovascular disease should fast only under medical supervision. Some health conditions, such as gastrointestinal reflux disease, are easier to manage when food intake is more regular, so those who have these conditions are not candidates for intensive fasting.
If you fast longer than 30 days, your body goes into starvation mode. This can lead to anemia, hypoglycemia, and electrolyte imbalances that can cause cardiac arrest and coma. Kidney and liver failure can also occur. People have died from prolonged fasts, usually because they were in a weakened state before fasting or fasted too long. Children are particularly susceptible: Never fast young children.
Four Common Things That Can Happen During Fasting
- Toxins can be released in the body causing headache and malaise. Drink more water. Take a sauna. Practice skin brushing. Rest. Take a detox bath. Do not take Tylenol (acetaminophen).
- You can become tired due to low blood sugar. Add honey or agave syrup to your teas or drinks. Eat some nuts or fresh fruit.
- You could become constipated. Drink more water. Take an herbal laxative.
- You could feel amazingly better! Keep up with a healthy lifestyle and whole, live foods diet, and practice intermittent fasting.
Going without and getting hungry now and then is clearly a healthy thing to do. For optimal results, fasting, like every other healthy activity, must be done sensibly, regularly, and in moderation. Many people who follow IF regimes report both physical and mental benefits, including improved energy and concentration, better sleep, and an overall heightened feeling of well-being.
Remember: you cannot improve health without reducing disease. You cannot increase longevity without prolonging health. Mastering fasting is the key to it all.