What is intermittent fasting, how does it affect insulin levels and why is intermittent fasting so effective?
Intermittent fasting refers to an eating schedule that requires a time period of at least 12 hours from when your body goes into a fasted state, to it's next fed state or meal. This is most commonly seen at an 8/16 hour split, with an 8 hour an eating period during the day, and then fasting the remaining 16 hours in the day throughout the night. However, there are various forms that include fasts up to 24 hours or more. With many proponents of intermitting fasting supporting overall weight management due to it's affect on your body's response to insulin, it also comes with major cellular, cognitive, metabolic and other health benefits.
As a society we have become accustomed to being a fed state at almost all times. With quick accessibility to food, we almost never need to go long periods without eating. Unfortunately for our bodies, this creates a constant elevated insulin response. When our insulin is high in our bodies, it signals us to store excess calories in our fat cells, creating more body fat. Then instead of burning these fat cells for energy, the body will use the glucose from one's last meal. This eventually leads to over used glucose burning pathways, and a reliance on glucose for energy. The body will begin to secrete even more insulin in response to being in a constant fed state, which can lead to obesity, low cholesterol, and even type 2 diabetes. Someone with insulin resistance will rarely get the opportunity to burn body fat, because when they run out of glucose from their last meal, they experience hunger for more. The solution? Intermittent fasting.
What are the benefits of intermittent fasting?
Intermittent fasting has been well researched, and it is proven to have many health benefits. The first and foremost benefit that is most commonly known is fat loss and improved insulin. This is due to a positive effect on insulin control in the body, by ultimately lowering insulin levels. As mentioned previously, in a fed state, insulin is elevated. On the contrary, in a fasted state, insulin is low. The reaction of the body from low insulin levels is to start utilizing stored fat in the fat cells for energy, rather than the glucose used in a fed state. Intermittent fasting therefore strengthens cellular receptors to insulin. This will ultimately lead to less overall body fat, by shifting the body into a fat burning state. Furthermore, because intermittent fasting allows the body to improve its ability to fuel itself from stored body fat and lower insulin levels, it has been proven to decrease the risk of obesity, obesity related conditions and other diseases such as diabetes.
Intermittent fasting also aids in Human Growth Hormone production, and has been shown to increase it by almost five times. This creates a "cleanse" for your body that essentially eats away damaged cells, recycles waste materials within these cells, and then repairs and regulates new cells. The reason that HGH is raised during a fasted state is because fasting activates the pituitary gland, where HGH is stored, which is otherwise suppressed during feeding. The production of Human Growth Hormone can be very beneficial to those looking to gain and/or repair muscle, due to its anabolic affects. Growth hormone production is also linked to the tissue repair, energy usage and anti-inflammatory affects of fasting which will be discussed below.
Intermittent fasting is known to show protective benefits to brain function, immune health and aging. While fasting, as mentioned previously, your body speeds up the production of new cells. As a by product, your brain neurons become more resistant to dysfunction and degeneration. Heightened insulin levels have been shown to suppress cognitive function, so being in a fasted state thus increases neuron function. The cellular production and detoxification process also induces stem cell self-generation, which greatly impacts the immune system and can reduce risk of chronic diseases such as cancer. Inflammation in the body is also reduced as a result of intermittent fasting which is a leading cause of many illnesses. Because your cells are able to detox and recycle themselves, your body can slow down its ageing processes in a fasted state as well.
There is also evidence to show that intermittent fasting regimes that limit day time food consumption actually improve one’s circadian rhythm and therefore metabolic health. This is essentially ones internal biological clock that determines when to perform vital physiological processes, in order to ensure they are being carried out optimally. It can also assist your body's ability to naturally shift between the sympathetic (fight or flight) and parasympathetic (relaxed state) throughout the day into the night, in order for higher quality rest, and overall lower cortisol levels, otherwise known as the stress hormone.
Intermittent fasting can be majorly beneficial not just towards increasing your bodies ability to utilize and burn stored fat, lower insulin levels and cause weight loss, but towards many other vital biological functions. When paired with regular exercise, you can access and increase some of the same benefits from intermittent fasting, by depleting glucose and glycogen during your workout rapidly in order to force the body to switch over into a fasted state and utilize fat for energy. However, it is important that you have sufficient protein and amino acids in your body during your fed state, in order to support muscle growth while losing fat. Supplementing with BCAAs during your workout and glutamine paired with 100% pure whey isolate immediately post workout is the most effective way to ensure your body responds the way you want it to, to burn fat, and maintain or grow muscle. By allowing yourself to monitor and restrict your eating habits to follow the fasting guidelines, you are not only benefiting your training, but prolonging your ability to live a healthy and optimal life.