Types of Intermittent Fasting
There are several different intermittent fasting protocols. Each of the different intermittent fasting techniques provides its own unique benefits allowing each to be used for different goals.
16:8: fasting period of 16 hours and an eating window of 8. This fast tends to be practiced several times per week or even daily.
5:2: eating pattern consisting of five days of normal eating following by only consuming around 600 calories on two consecutive days.
Alternate Day Fasting: In this form of fasting, you fast every other day. Some people will allow for very low-calorie intake on fasting days.
OMAD: OMAD or one meal a day is just as it sounds. You only eat one meal per day and all of your calories are consumed during this short feeding window.
Circadian Rhythm Fasting: this type of fasting attempts to mimic the circadian rhythm and generally involves eating between 11 a.m. and 7 p.m.
Benefits of Intermittent Fasting
Research on the benefits of intermittent fasting is mounting. A review published in the New England Journal of Medicine in 2019 said, "Evidence is accumulating that eating in a 6-hour period and fasting for 18 hours can trigger a metabolic switch from glucose-based to ketone-based energy, with increased stress resistance, increased longevity, and a decreased incidence of diseases, including cancer and obesity." A powerful statement from an established publication.
Let's dive into the individual effects of intermittent fasting and fasting diets.
#1 Can Aid in Fat Loss
Fasting has become popular for its weight loss benefits. Fasting can produce robust body fat loss due to low insulin and blood sugar levels which allow the body to transition into a state of fat burning.
Research supports the fat loss mechanisms of fasting by supporting fat loss ranges from 2.5-9.9% [*].
Research has also shown that intermittent fasting is effective at decreasing leptin, a hormone that plays a role in our hunger levels. Intermittent fasting can also increase adiponectin, a glucose regulating hormone that plays a role in insulin sensitivity and inflammation. Adiponectin is typically lower in obese individuals than it is in lean individuals [*].
This is why we are seeing more and more clinicians using fasting in obesity medication and any condition where body weight needs to be managed.
#2 Improves Insulin Resistance and Type 2 Diabetes
Insulin resistance is a main driver of many modern-day illnesses, including Type 2 diabetes. Type 2 diabetes is when the cells no longer respond to the amount of insulin your body produces in response to food. Intermittent fasting has been found to directly lower insulin resistance which could help improve Type 2 diabetes. Research has found that fasting can help reduce diabetic medication and in some cases even completely remove the need for medication
It is important for anyone with diabetes to consult with a physician that understands fasting to receive care in practicing this dietary technique and reducing medication appropriately.
#3 Reduces Inflammatory Markers and Oxidative Stress
Inflammation is one the body’s natural defense mechanisms that is used to fight off infections. Like most things, too much of a good thing is never a good thing. Research is now discovering that too much inflammation can lead to an increased risk for many chronic illnesses.
Inflammation can also be triggered by eating too often, too much, and by eating unhealthy foods.
Intermittent fasting is a great strategy for combating inflammation. Oxidative stress, which is the accumulation of reactive oxygen species in the cells, is believed to be a driver of inflammation. A 2013 study found that fasting for a minimum of 24 hours reduced oxidative stress [*].
#4 Brain Benefits
Intermittent fasting has also been shown to have many benefits for the brain.
Intermittent fasting increases something called brain-derived neurotrophic factor or BDNF. BDNF is a protein that promotes the growth and survival of neurons or nerve cells [*].
Intermittent fasting can also promote better brain health by reducing neuroinflammation allowing it to reduce the risk of certain neurological conditions like [*].● Parkinson’s disease
● Transient ischemic attacks
● Alzheimer’s disease
Intermittent fasting can also produce short-term brain benefits by increasing ketones, which provide more fuel to the brain for more focus and mental clarity.
#5 Cellular Repair/Anti-Aging
Fasting causes your body to go into repair mode. Autophagy, which can be broken down to self-eating; “auto” means self, and “phagy” means eat [*], is the body’s evolutionary process to clean out damaged cells or the damaged components of cells.
This natural process is critical for our long-term health and when we are always in a fed state, it rarely occurs. Incorporating fasting allows your body to end a repair mode that will provide long-term health benefits.
DNA degradation is a primary component to aging and is inevitable to some degree as we age. Fasting can accelerate DNA repair to help slow the aging process. Fasting also increases natural antioxidant levels, which are very important for slowing aging[*].
Research on fasting and calorie restriction for longevity has been studied in worms for decades. While we are still working to translate these findings to humans, there is also an increasing amount of evidence that promoting low insulin levels can manipulate aging on a genetic level via the DAF-2 insulin-like signaling pathway.
This pathway mediates lifespan, stress resistance, and immunity. While the DAF-2 gene is not found in humans, there are several pathways that are very similar to this pathway in the way it functions and its structure.
#6 Digestive Rest
We don’t realize how long it takes to digest the food we eat. While you may think it only takes a few hours, the body is actually still digesting your meal for 10+ hours after eating. When we are constantly eating, we create a backlog of food that isn't optimal for our digestion or our overall health.
Being in fasted state allows your digestive system to work through the food you have already eaten and rest up for your next feeding.
#7 Heart Health
Intermittent fasting may also provide benefits to your cardiovascular system through three benefits:
- Improving cholesterol
- Reducing oxidative stress
- Circadian rhythm optimization
Intermittent fasting helps improve HDL cholesterol, triglycerides, and even blood pressure, especially when followed up with a lower-carb whole food diet.
Inflammation driven by oxidative stress plays a role in heart health. Research has found that intermittent fasting can help reduce inflammation levels and increase antioxidant production.
Nighttime eating decreases sleep quality and quantity and creates insulin resistance and leads to heart disease[*]. Intermittent fasting prevents you from overeating at night allowing you to get better heart-healthy sleep.
#8 Cancer prevention and treatment
Fasting is now commonly used in combination with cancer treatment.
Cancer cells thrive on glucose and require a great deal of energy to continue growing. When we remove this energy during a fast we are able to starve cancer of its primary form of energy.
Animal studies have found that combining fasting with standard of care can help combat aggressive forms of cancer These mice had either a glioblastoma or pancreatic cancer [*].
Is Intermittent Fasting Safe?
Intermittent fasting is safe for the majority of people. However, it is important to make sure you are practicing intermittent fasting for the right reasons and refueling your body during your feeding window. Fasting may not be a great fit for those with eating disorders and pregnant and breastfeeding women should avoid fasting if it leads to a big calorie deficit. If you have any medical conditions or are taking medication please consult with a healthcare provider (doctor, dietitian, etc.)before trying intermittent fasting.
Tips for Intermittent Fasting
Take things slow
- You do not need to jump into a 24-hour fasting plan or even a 16:8 hour window. Depending on your meal frequency before implementing intermittent fasting, it may even be beneficial to begin with 12 hours of fasting and 12 hours of eating
Are you hungry or bored?
- Sometimes we confuse boredom with hunger and food has become a source of entertainment as it has become more palatable and less nutrient-dense. If you find yourself hungry during your fast, try drinking some water or having some electrolytes.
Supplement with electrolytes
- Electrolytes are important minerals that play a role in nearly every bodily function. When you fast and eat a low-carb diet you lose electrolytes that can lead to symptoms like brain fog, fatigue, muscle cramps, and hunger. Supplementing with electrolytes and consuming electrolyte-rich food during your feeding window is a great strategy to combat this.
If you are not feeling well, EAT!
- If you are experiencing lightheadedness or extreme fatigue it is a good idea to eat. It can be tempting to fast through your eating window. Listen to your body and break your fast with a healthy balanced meal. Ideally, one that contains animal protein, healthy fats, and maybe some veggies.
- Fasting can cause dehydration so be sure to stay hydrated during and after your fast.
- After not eating for several hours it may be tempting to eat a surplus of food within a few minutes. Ease your way into a fed state by eating a light meal rich in protein and healthy fat.
Experiment with different meal timing
- Each fasting protocol mentioned earlier in this article can react differently with your body. Experiment to find which one works best for you and your goals
Ketogenic diets and Intermittent Fasting
Ketogenic diets (and any diet low in carbohydrates) and intermittent fasting pair very well with each other and many people who practice a ketogenic diet automatically intermittent fast due to the lack of hunger provided by the diet.
Since ketogenic diets induce a state of ketosis, fasting is quite effortless on keto because fat adaptation has already occurred. Keto and fasting are especially incredible duo if your goal is losing weight or increasing brain function.
Intermittent fasting is a dietary technique that can provide many benefits to our bodies. Whether you are looking for fat loss, anti-aging, or improved heart health, fasting is a powerful tool to help you reach your goals.