Autophagy is a word that's derived from ancient Greek roots: auto means self and phagos means devouring. It's a process that helps the body use available energy efficiently, and it recycles the materials needed to grow additional healthy cells. Autophagy inside a cell takes place when a membrane is formed around unusable cell parts. Those pieces of the cell are then broken down and expelled, so they can be reused to make new cells. Entire cells that are old and functioning poorly are also recycled to make healthy new ones through this process.
Eliminating non-functioning organelles and poorly formed proteins also takes them out of circulation and limits the damage they can inflict on the body. As mitochondria get old, they give off charged particles that can cause cellular degradation and cell mutations. The elimination of these defective mitochondria prevents exposure to mutations that can cause cancer. Also, prolonging the autophagic cycle can eliminate cancer cells, as the turnover of organelles and proteins accelerates. In cancer treatment, inducing autophagy has been successfully used as a therapeutic method of killing cancer cells.
Defense Against Pathogens
When cells are infected with pathogens, autophagy is part of the process that eliminates them. The same biological mechanisms that cause the destruction of mitochondria also prompt an attack on cellular pathogens such as the bacterium responsible for tuberculosis. Inside each cell, there are lysosomes, small pockets that have separate membranes containing digestive enzymes. These enzymes break down defective organelles and pathogens into molecules that can be reused for energy or building blocks by the body.
One study in 2013 strongly suggested that intermittent fasting improves cognitive ability. Rats fed only every other day showed clear signs of better memory and learning ability. They also had a thicker neuronal cell layer and their cells showed lower oxidative stress compared to the control group. The effect of autophagy on brain cells is highlighted by the absence of it in certain neurological conditions.
In Parkinson's disease, a neurodegenerative disorder, cells lack the chemical marker that signals the body they need to be destroyed. Alzheimer's disease is thought to be related to a buildup of proteins in neurons that eventually entangles the neuronal pathways in the brain. Since one of the tasks performed by autophagy is the removal of defective proteins, an increase in autophagy should promote cognitive health.
Cells can be stressed for many reasons, including lack of nutrients and damaged intracellular organelles. Unstable molecules called free radicals also cause cell damage. When this occurs, it signals the body to ramp up autophagy. Oxidative stress can cause changes to DNA and cellular components, and autophagy defends the body from these effects by eliminating the damaged cells. Exercise is also a form of stress for the body, and it induces autophagy in part because of microscopic tears in your muscle fibers caused by working out.
Obesity and Diabetes
There may be a link between the suppression of autophagy and type 2 (adult-onset) diabetes. Diabetes is caused by the body's inability to regulate glucose metabolism in the presence of excessive caloric intake. This leads to insulin resistance and a dangerous buildup of glucose in the bloodstream, causing cellular stress and chronic inflammation. Obesity triggers the release of a protein that increases the rate of inflammation and suppresses the rate of autophagy. It's believed that this suppression is a link to the development of insulin resistance.
Inflammation and Immunity
When cells that are damaged or no longer metabolically active remain in the body, they can become a hub for inflammation. Since many diseases have been linked to inflammation, removing these defective cells could prevent autoimmune and other types of disorders. One area currently being explored is the relationship between autophagic activity in the body and autoimmune diseases like lupus and Crohn's disease. Elevated levels of autophagic activity could either signal an overactive immune response or an attempt by the body to overcome genetic suppression of autophagy.
AUTOPHAGY AND GOOD HEALTH
How does autophagy apply to your health and fitness?
Intermittent fasting promotes autophagy, which has a positive impact on health. Autophagy prevents the accumulation of mutations in the mitochondria, the powerhouse organelle of the cell. There's also some evidence that autophagy encourages the release of growth hormone. This hormone maintains the health of organs and tissues, but its release slows down as we age. Having an adequate supply of growth hormone increases bone density, muscle mass and exercise capability while it decreases body fat.
How does this process work?
When your body has no energy resources from food to power it, autophagy allows unused proteins to be taken apart. Then, amino acids from the proteins are used to make new proteins that are essential for survival. A separate membrane inside a cell, called a lysosome, is able to enfold and capture defective parts and dissolve them into separate molecules. This can supply raw materials for the cell, and energy for cellular processes is freed up when lysosomes devour lipids and starch.
This process is related to, but not the same, as using fat molecules for energy through ketosis. When the energy you expend through exercise exceeds your intake of nutrients, the body can turn to autophagy or ketosis for energy. The difference is that ketosis focuses on switching your body's metabolism from using carbohydrates to burning fat for fuel. Ketosis that results from fasting and limiting carbohydrates is marked by ketone bodies in the bloodstream, and research shows that these ketone bodies may protect the brain through increased neuronal autophagy.
As the human body grows older, the maintenance abilities of autophagy decline. Scientists hypothesize that this is a large part of the reason we see more cancer, diabetes and cognitive decline in older populations. If that's the case, then accelerating autophagy should, in theory, slow down the aging process. So, how can you increase this ability in your own body?
Studies with animals have consistently resulted in the same outcome: a long-term low-calorie diet resulted in longer-lived subjects. More recently, this result has been shown to be due to calorie restriction raising the level of autophagy and keeping it at a high level. This is especially beneficial to the liver, which is the central clearinghouse for recycling old or damaged cells and providing energy for the body's functions. By preventing obesity, calorie restriction can also eliminate the presence of proteins linked to insulin resistance and diabetes.
Also known as short-term food restriction, fasting is another method of raising the autophagic activity in your body. One 2010 study identified this benefit in both body tissues and in the neurons of the brain. Although attempts are being made to develop drugs that enhance autophagy, the study concludes that "food restriction is a simple, reliable, inexpensive and harmless alternative to drug ingestion." There is one caveat about using targeted short-term fasting, however. Fasting should be short-term only and not taken to extremes. It turns out that excessive food restriction can actually inhibit autophagy.
Getting regular exercise is thought to have a positive impact on a variety of health problems. This may be due in large part to its ability to stimulate autophagy in multiple organs of the body. As one example, it's possible that this could be the factor that reduces glucose intolerance in people who exercise regularly. Exercise has been identified as improving the health of the heart, muscles and brain, and autophagy may have a key role in all of these benefits.
HOW TO OPTIMIZE YOUR HEALTH
Now that you know you can induce higher levels of autophagy through fasting, the next step is to devise a fasting routine that will work for you. The primary goal is to have a short window of 6 to 8 hours for eating and a longer period of 16 to 18 hours in which you don't eat. Besides promoting autophagy, this type of routine inevitably restricts calories, another catalyst for autophagic activity. Whatever fasting method you choose, be sure to drink plenty of water. You can also have calorie-free beverages, coffee, tea and sugarless gum. And a small amount of milk or cream in your hot beverages shouldn't throw your plan off. Here are a couple of different techniques that work well for intermittent fasting.
Lose Fat, Build Muscle with a 16-Hour Fast
One key to making this routine work is sticking to the same eating window each day. Your body will eventually adapt to a set eating and fasting schedule, and it will get easier for you to stick with it over time. If you need to start with a 12-hour fast and work your way up to 16 hours, that's fine. To build muscle, you'll need to engage in some kind of exercise, even if it's just walking a few blocks each day.
What you eat during the 8-hour window will make a difference in your success at converting unwanted fat to new muscle. You'll need protein as building blocks for muscle tissue, 'good' fats for energy, and fruits, vegetables and nuts for all of the vitamins and nutrients they provide. It's okay to indulge occasionally in a piece of pie, but the best way to build muscle is to eat your fill of healthy foods during your meal window.
Restrict Calories with a 24-Hour Fast Twice Weekly
This is harder to accomplish for most people, but it's a way to significantly cut your calorie consumption in addition to fasting. You can time the fast however it works best for you, but dinner-to-dinner is a method that works well for many. Just have an early dinner, and then fast from that point on until the next day at your regular dinnertime.
A Fasting Workout Plan
Combining fasting with exercise may seem counter-intuitive at first. You might think that exercise will be more difficult without the energy you get from meals, but it can definitely work for you. As long as your body is burning fat for energy, it's not cannibalizing protein from your muscles. This helps you transform to a leaner physique by redistributing body mass to muscles instead of fat deposits.
When you do eat, the same calories that would have been spread out over a longer period are concentrated in a smaller window of time. This gives your muscles more calories at one time to aid in recovery and increase muscle mass. That's why it's possible to lose several clothing sizes with only a twenty-pound weight loss. Your muscle tissue becomes denser and more compact, and this is what's meant by the phrase, "muscle weighs more than fat."
Take Charge of Your Health
All living things except for a couple of types of bacteria rely on autophagy to regulate the availability of raw materials needed for cells to survive. That includes not just animals but slime molds, yeast, fungi, plants and even single-celled protozoa. Over the last two billion years, living things have evolved this defense mechanism to avoid being wiped out by famine. Autophagy is an adaptive strategy that enhances human health, and you have some control over its effects on your own health through calorie restriction and intermittent fasting.