Intermittent Fasting: A Powerful Tool for Weight Loss, Blood Sugar Balance & Brain Health
There are very few nutrition interventions that promote healing, longevity and weight loss without an investment of time and money. While there are plenty of fad diets that make these empty promises, most come up short in terms of long-term results and supported research. One of the few exceptions to these fad diets is intermittent fasting, which has proven in numerous research studies to enhance weight loss in addition to many other valuable health benefits. The body was not meant to eat 24 hours a day which may explain why intermittent fasting interventions are showing promising outcomes for weight loss, balanced blood sugar levels, improved brain health, decreased levels of inflammation and more.
Fasting should not to be confused with the idea of starvation, but rather a controlled abstinence of food for a designated period of time. The body is designed to fast for a certain window of time in order to repair itself. Researchers are finding that eating at all times of the day and night undermines the body’s innate repair and protective mechanisms which can trigger metabolic and inflammatory responses. What this means is that abstaining from food intake for a window of time can improve the body’s physiology and mitochondrial function, leading to a powerful, natural weight loss and healing solution.
What is Intermittent Fasting?
Let’s start with the basics of intermittent fasting. Again, this is not a starvation diet but rather avoiding food consumption for a window of time or significantly restricting calories a few times per week. This allows the body to release energy that is stored as fat while also increasing insulin sensitivity, inducing weight loss, reducing appetite, lowering levels of inflammation, improving cognitive function, and more. When referring to intermittent fasting regimens, the following three are the most common:
This refers to routinely abstaining from energy intake for a designated period. Windows of time-restricted fasting typically range from 12-16+ hours, depending on the individual and their health needs and goals.
Modified Fasting Regimens
Modified fasting refers to dropping caloric intake for a few days each week. This strategy is also known as the 5:2 diet. This is when you consume your usual intake for five days each week and then restrict energy intake for the other two. The restriction days are usually non-consecutive and this is when you cut back to 20-25% of your usual intake.
There are a variety of fasting routines for religious or spiritual purposes. One of the most common and well-researched holidays is Ramadan which is when participating individuals fast from sunrise to sunset, which is approximately 12 hours in length.
What are the Benefits?
1. Promotes Weight Loss
There is a growing body of evidence that substantiates the effectiveness that intermittent fasting can have on weight loss. There are a few possible explanations for the waist-trimming benefits, namely that it decreases insulin resistance. Insulin resistance and higher levels of insulin cause people to hold onto more visceral (belly) fat. Decreasing insulin resistance and improving insulin sensitivity, makes it easier for people to lose weight around their middle section. Intermittent fasting also improves the gut microbiome which has been linked to weight benefits. Other important benefits include improving the human circadian rhythm which is thought to be associated with a healthy weight and decreases appetite. Men enrolled in a recent short-term study of two weeks fasted for 11 hours throughout the nighttime and experienced 1.3% greater weight loss.
2. Improves Circadian Rhythm
A persons’ circadian rhythm or master biological clock tells you that it’s best to sleep when the sun goes down and wake when the sun rises. Intermittent fasting regimens that limit food intake to hours of daylight seem to leverage circadian biology. This means that when it’s dark, the body is meant to sleep and fast but during daylight, the body is meant to be awake and feed. Based on circadian rhythms, the optimal times for a person’s metabolism and energy production are during daylight and the best time to fast is at night.
3. Improves Gut Health
A person’s gut microbiome plays a huge role in energy metabolism, glucose tolerance, and regulation of inflammation. Research has demonstrated that when you take stool from an obese mouse and inject it into a lean mouse that the lean mouse gains weight without changing its diet or physical activity. The composition of bacteria and metabolites in the gut microbiome play a role in maintaining a healthy weight. Because the GI tract is greatly influenced by circadian rhythms, it appears that fasting at night may in turn promote healthy bacteria and weight maintenance.
4. Increases Insulin Sensitivity
Fasting is an effective way to deplete the livers stores of glucose, which is called glycogen. Decreased glycogen stores can lead to mild ketosis. This has been shown to improve insulin sensitivity which helps with blood sugar control, weight loss, and more. A recent pilot study demonstrated that a 16 hour fast for five weeks improved insulin sensitivity, blood pressure and reduced oxidative stress in men. These results were also independent of weight loss. This was the first human study to demonstrate cardiometabolic benefits that are not related to dropping excess pounds.
5. Induces Autophagy
Fasting induces autophagy which is the process in which the body’s cells are able to recycle damaged protein and mitochondria. Think of it as the cleaning crew that goes into a business at night when the operation is closed. This is an important job that is necessary for proper repair. A 2017 review paper indicated that the cellular mechanism by which intermittent fasting improves health and reduces disease involves adaptive cellular response signaling pathways that promote autophagy, DNA repair and mitochondrial benefits.
6. Improves Cognitive Function and Protects Against Neurodegeneration
Nutritional interventions such as intermittent fasting have influenced brain aging and neurodegeneration in rodent models. Leading neurologists such as Dr. Dale Bredesen incorporate fasting into protocols for Alzheimer’s Disease patients. When it comes to cognitive function, there are a few reasons for why intermittent fasting may be beneficial. One of the main reasons that people notice cognitive improvements is because fasting increases insulin sensitivity. This helps lower levels of insulin which is a pro-inflammatory, fat-storing hormone that is also associated with brain damage.
A second reason is that intermittent fasting boosts levels of Neurotropic Factors called Brain Derived Neurotropic Factor (BDNF). Neurotropic factors are molecules that repair damaged neurons and have been associated with the prevention of neurodegenerative disease. A 2017 study assessed individuals that participated in the Muslim holy month of fasting, Ramadan. Individuals that participate in Ramadan abstain from eating from sunrise to sunset. Compared to the control group, individuals that fasted throughout the month of Ramadan experienced 25-47% higher levels of BDNF.
7. Promotes Longevity
Two effective ways to promote a maximum lifespan and health-span include caloric restriction and physical activity. Restricting calories and avoiding overeating in general has been shown to delay aging processes and promote longevity. More longevity research is needed as it pertains to intermittent fasting in humans but the number of markers that improve via fasting have been associated with an extended lifespan. Incorporating intermittent fasting or caloric restriction is associated with lower levels of inflammation, increased insulin sensitivity, proper autophagy, and increased cellular stress resistance. All of these factors are associated with longevity.
Intermittent Fasting Recommendations:
1. Try a minimum of a 12-hour fast
I recommend as a general principle to try fasting for at least 12 hours most days of the week. That means if your last bite of food was taken at 8pm then you’d wait until 8am the next morning to eat again. During your period of fasting you can drink water, black coffee or tea with nothing added to it since none of these drink options contain calories. This allows a window of time for the body to break from digesting food and to simply focus on repairing itself.
If the 12 hour fast works well then you may increase to a 14-16 hour fast which means narrowing your window of eating to 8-10 hours. If you stop eating at 8pm at night then you would wait until 10am-12pm to eat for the first time the next day. The people that seem to benefit most from this approach are those that have difficulty controlling blood sugar levels, those that are always hungry and individuals with cognitive decline. Experts in the Alzheimer’s community recommend a 14-16 hour fast for individuals that are either a homozygous or heterozygous carrier of ApoE4, a genetic allele that is associated with an increased risk for Alzheimer’s Disease and Cardiovascular Disease.
At first you may feel hungrier from incorporating fasting into your diet and that often means that the body needs to be retrained on when it expects to eat.
2. Incorporate 1 Tbsp MCT oil
MCT stands for medium chain triglycerides which is essentially a fat that is medium in length when it comes to its carbon chains. Coconut oil is made up of about 60% medium chain triglycerides but you can purchase 100% medium chain triglycerides in its concentrated form. The benefit of doing so is that MCT oil is absorbed differently than other fats. They are transported directly from the intestinal tract to the liver which can slightly raise a person’s metabolic rate. You can also incorporate 1 tbsp of MCT oil into black coffee or tea in the morning without breaking your fast because of the fat composition.
3. Break your fast with warm lemon water
Whether you are fasting for 12 hours or 16 hours, drink a cup of warm lemon water when you are breaking your fast. This is an effective way to optimize the liver’s ability to clear toxins from your system. This is also an easy way to get a boost of polyphenols and vitamin C. If you are frequently on the go then consider purchasing True Lemon Packets which are crystalized lemon juice packets that can easily elevate your water.
4. Consider increasing potassium intake
There’s some evidence that fasting can increase electrolyte needs and this is especially when fasting for longer periods of time. The two most prevalent electrolytes that we lose the fastest are sodium and potassium. Since most people are not lacking sodium in their diet, potassium is the electrolyte to pay attention to. Ensure that you are eating plenty of potassium rich foods such as avocado, bell peppers, sweet potatoes, banana, strawberries, etc. And a potassium supplement may be warranted depending on the duration of your fast.
5. Avoid fasting if you feel hungrier later in the day
For some people, skipping meals leads to more intense cravings later on in the day. This is especially true for individuals who carry genetic variants that predispose them to lower feelings of satiety. It’s reported for these individuals that skipping breakfast or other meals leads to more intense cravings later in the day. If you don’t know your genetic profile then pay attention to your body’s levels of satiety throughout the day. If eating later in the morning causes more cravings later in the evening then reduce to a 12 hour fast.
Intermittent fasting, especially when it comes to longer fasting periods like 14+ hours may not be for everyone. It’s not recommended for individuals that are pregnant, those that experience lower levels of satiety from skipping meals and individuals with Type 1 Diabetes. Talk to your Dietitian or Doctor prior to making changes to your diet.
Contributing research: Charlie Ross