Fasting, we’ve all heard of it, but what is it? Fasting is purposefully going without food for a set period of time. Religions include fasting, in fact every culture in every country has practiced some form of fasting for thousands of years. On some level, our body is designed to fast, as you do it every night when you sleep.
While there is much controversy on the issue, most medical experts agree that fasting is not a healthy weight loss tool. In fact, it can make weight problems worse by slowing the metabolism. There are some experts that have begun to study fasting for other purposes, such as fighting disease. This article is intended to provide information on some of the new research being done in this area but not to endorse fasting, particularly without consulting a physician first. So what happens to your body when you fast?
Your body initiates important cellular repair processes and changes hormone levels to make stored body fat more accessible.
Some changes that occur in your body during fasting include:
• Blood levels of insulin drop significantly, which facilitates fat burning.
• The blood levels of human growth hormone may increase as much as 5-fold. Higher levels of this hormone facilitate fat burning and muscle gain, and have numerous other benefits.
• The body induces important cellular repair processes, such as removing waste material from cells.
• There are beneficial changes in several genes and molecules related to longevity and protection against disease.
Many of the benefits of intermittent fasting are related to these changes in hormones, gene expression and function of cells. See here.
“While fasting for a day or two is rarely a problem if you are healthy, “it can be quite dangerous if you are not already eating a healthy diet, or if you’ve got liver or kidney problems, any kind of compromised immune system functioning, or are on medication — even Tylenol,” says Fuhrman, a family physician in Flemington, N.J.. “We know that the body is unable to rid itself of toxins when we eat a diet low in nutrients,” and that applies to most Americans, even those who think they are healthy, he says. “Americans eat 51% of their diet from processed foods and foods low in phytochemicals and antioxidants,” he says. “So you see a buildup of waste products in the cells — AGE, advanced glycation end products — that build up in cellular tissues and lead to atherosclerosis, aging, diabetes, nerve damage, and the deterioration of organs. This is basic science and physiology every doctor learns in medical school.” Along with improving your overall diet, fasting is one solution to that buildup of AGE, according to advocates like Fuhrman. “Fasting allows the body to most effectively remove these waste products,” he says. “The body is designed to fast; we do it every night.” How does fasting remove toxins from the body? When you go without eating for more than a day or two, the body enters into ketosis. Ketosis occurs when the body runs out of carbohydrates to burn for energy, so it burns fat. “And the fat is where the body stores many of the toxins it absorbs from the environment,” Fuhrman says.” See here.
Fasting interferes with your immune system’s activity which can be overreacting in the case of many auto-immune diseases. A study, conducted by Dr. Valter Longo and colleagues from the University of Southern California (USC) in Los Angeles, found periods of fasting – 2-4 days – may even “reboot” the immune system, clearing out old immune cells and regenerating new ones – a process they say could protect against cell damage caused by factors such as aging and chemotherapy.
Cancer is a disease characterized by uncontrolled growth of cells. Fasting has been shown to have several beneficial effects on metabolism that may lead to reduced risk of cancer. Although human studies are needed, promising evidence from animal studies indicates that intermittent fasting may help prevent cancer. See here.
In June 2014, Medical News Today reported on a study suggesting periodic fasting – defined in the study as 1 day of water-only fasting a week – may reduce the risk of diabetes among people at high risk for the condition. Intermittent Fasting Can Reduce Insulin Resistance, Lowering Your Risk of Type 2 Diabetes. Type 2 diabetes has become incredibly common in recent decades. Its main feature is high blood sugar levels in the context of insulin resistance. Anything that reduces insulin resistance should help lower blood sugar levels and protect against type 2 diabetes. Interestingly, intermittent fasting has been shown to have major benefits for insulin resistance and lead to an impressive reduction in blood sugar levels. In human studies on intermittent fasting, fasting blood sugar has been reduced by 3-6%, while fasting insulin has been reduced by 20-31%. See here.
Fasting has also been used in fighting depression and other physiological issues like stress. Fasting allows a person to take a first step in taking control in their lives and start making healthier food choices. It allows people to practice discipline and self sacrifice. It allows individuals to recognize body cues, particularly in comparison to emotional eating cues. Fasting, however, may exacerbate conditions in people who already struggle with disordered eating such as anorexia or bulimia. Experts agree that fasting only works if it is framed by good nutrition both before and after.
People who fast commonly experience dehydration, largely because their body is not getting any fluid from food. As an athlete this is a very serious concern. Particularly if you live in an area where temperatures and humidity already impact performance. Additionally, if you are used to having breakfast, lunch, dinner and snacks in between, fasting periods can be a major challenge. As such, fasting can increase stress levels and disrupt sleep. Dehydration, hunger or lack of sleep during a fasting period can also lead to headaches.
While fasting might not be pleasant, does it impact performance? Most people seeking the health benefits from fasting while also trying to participate in a normal daily routine, are not fitness professionals who can optimize training and fasting for peak physique display. Luckily, there is a wealth of athlete specific fasting research thanks to the religious observance of Ramadan. Ramadan fasting includes abstaining from both food and water from sun up to sundown. Many studies show athletes of all shapes and sizes doing just fine without both food and drink. But there are also some downsides.
Performance—for the most part—can be maintained on an empty stomach. Overall, it seems athletes with stable mindsets do the best. So craving food and obsessing over hunger is foregone failure. When venturing into intermittent fasting, it takes time to get used to new eating patterns. The big take home here is that hunger is apparently what you make of it. Meaning, a hungry athlete isn’t going to perform well unless they are mentally conditioned to accept hunger as an arbitrary feeling. Most people, however, associate hunger with depletion. It should also be noted that while these studies did test many different athletes from middle distance runners to football and soccer players, they did not test endurance athletes like marathoners.
To decide whether or not fasting is for you, and to see how to arrange it around your activities, first ask yourself if you thrive or dive on hunger? If you can manage hunger fine, the Ramadan studies show that most performance markers can be maintained. See here.