Health: Intermittent Fasting
Contributed by my very good friend Cecily Anne Clark-Ganheart, MD, FACOG @fastingworkgirl
Intermittent fasting. These two words have gained much traction over the past few years. However, you may wonder if this approach (used for eons) is right or beneficial for you. Physicians, celebrities, and many others have created a revitalized interest in this concept. This is evident by Terry Crews' discussions on incorporating intermittent fasting into his weight lifting routine, to Dr. Jason Fung’s book, The Obesity Code, and the recent case series in the British Medical Journal describing the therapeutic use in the treatment of diabetes. We are beginning to awaken our innate power which lies within each of us-- the potential for self-healing. This self-healing includes weight loss and an increased sense of overall health and wellness.
Beneficial promotion of gut flora
Promotes the “browning” of white adipose tissue
Improved insulin sensitivity
1) Reduces inflammation
Intermittent fasting is associated with decreases in inflammatory markers, such as Interleukin-6 (IL-6) and C-reactive protein (CRP). A study of Ramadan participants, in which fasting occurs from sunrise to sunset, demonstrated beneficial effects on several markers of inflammation, including decreased levels of IL-6 and CRP, compared to their non-fasting counterparts. Studies of patients suffering from ischemic stroke suggest intermittent fasting has the potential role to decrease oxidative injury, reduce inflammation and protect against cell death. This is plausible given the reduction of inflammatory markers observed as insulin resistance is improved. Inflammation plays a role in many chronic diseases. Therefore, a reduction of inflammation is a great thing!
2) Beneficial promotion of gut flora
Many researchers are exploring the connection between the gut microbiome and the link to chronic health conditions, including obesity. Studies involving fecal transplants in mice demonstrate that while individuals may have the same caloric intake, various profiles in gut bacteria determine how much energy is harvested from our calories. Obese mice (and humans) tend to have greater amounts of Firmicutes and lower amounts of Bacteriodes than their lean counterparts. This gut profile lends itself to potentially increasing the amount of fermentation by gut microbiota, thus leading to greater caloric harvesting from the meal compared to lean individuals. Given the link between obesity, insulin resistance, and altered gut flora, it is plausible that an improvement in insulin resistance can also shape the microbiome and its interaction with obesity.
3) Promotes the “browning” of white adipose tissue
As adults, white adipose tissue is the predominate fat type in our bodies. However, as infants, we possess large amounts of brown fat. Brown fat provides the ability to provide thermal energy without the need for shivering. You may have heard of the recent trend of “cold baths”, in which individuals spend time in freezing temperatures in an effort to “brown” white adipose. Since the mitochondria are “uncoupled” in brown fat, they generate large amounts of heat. This in turn creates increased energy expenditure and is thought to increase metabolism. Additionally, beige fat (formerly white adipose tissue which has undergone “browning”) is thought to have additional metabolic benefits, such as increased insulin sensitivity. While we are certainly not recommend cold, ice baths, intermittent fasting may promote a beneficial affect on metabolism through the “browning” of white adipose tissue. Given that our adipose tissue is a metabolically active organ, the potential for intermittent fasting to create a more favorable fat profile is huge.
4) Improved insulin sensitivity
Insulin resistance is at the center of many disease states, including obesity. Many obesity-related health conditions share insulin resistance at its core. Reducing insulin resistance assists in the improvement and even reversal of many disease states. A novel study performed in 1985, and updated in 2005, demonstrated improved insulin sensitivity with 20 hours of fasting. Adiponectin levels also increased. Increases in adiponectin levels are associated with decreased rates of obesity. Additionally, when circulating insulin levels are high, it is difficult to lose weight and mobilize fat stores. Improving insulin resistance through intermittent fasting not only assists with a more favorable hormonal profile, but also increases our ability for weight loss.
5) Weight loss
Many people have heard of the best seller by Dr. Jason Fung, entitled, The Obesity Code. In this book (which I highly recommend reading), Dr. Fung discusses the mechanism of obesity in great detail and provides his experiences with intermittent fasting. Dr. Fung is the head of the Intensive Dietary Management Program, based in Toronto, Canada. In his clinic, he has help thousands of patients tackle their obesity, and related disease states, through intermittent fasting. After reviewing the above benefits of intermittent fasting, it is easy to see why this way of life would also assist in decreasing body weight. A review of potential treatment strategies to combat obesity and assist with maintenance suggested intermittent fasting may play a role in the induction of weight loss and it’s its maintenance.
What exactly is intermittent fasting?
Intermittent fasting, simply put, is refraining from food or calorie-containing beverages for a period of at least 12 hours. While you may be familiar with this definition, it is typically desirable to extend this to a minimum time requirement of 16-18 hours. However, I find that it is much more realistic to work up to this goal, particularly if you are used to eating every two to three hours.
There are several protocols that vary both in timeframes and techniques. The most popular ones include:
16:8: This involves fasting for a period of 16 hours, with an eight-hour eating window. With this method, it is important to attempt to minimize nighttime eating. Therefore, a practical way to begin is to consume your last meal by 6-7pm (earlier during the winter months, if possible). The following day, the first meal is delayed until 11am or 12 noon. Some people find it more beneficial to do a 18:6 regimen, that is, 18 hours of fasting with a six-hour eating window. Many people fast anywhere from three to four times per week to daily.
One meal a day (OMAD): This is another popular technique, which involves consuming one, nutritious meal daily. It is important to consume adequate calories with this approach to ensure this way of eating doesn’t become a method of chronic caloric restriction (more on this in the months to come). Many people start off with incorporating this 3-4 times a week.
Alternate-Day Fasting (ADF): Alternate-day fasting involves eating nutritious meals throughout the day, followed by fasting the entire day and night on the following day. Though not as mainstream as the previously described methods, many people are finding weight loss success with ADF.
5:2 diet: The five and two diet involves eating nutritiously through out the week for five days. On days 6 and 7, followers of this approach consume 500-600 calories a day. This is my least favorite approach, due to the focus on caloric restriction; however, many people find success with this practice. Additionally, it may serve as an introduction to other fasting protocols, particularly if one has difficulty with the above methods.
Extended fasting: This involves fasting for periods over 48 hours. This is certainly not required for weight loss or health benefits. While the application may be beneficial in some medical approaches, I would like to stress that discussion with a healthcare provider whom can evaluate your personal situation for potential contraindications is key. Our focus over the next year will discuss intermittent fasting, rather than extended fasting.
A practical way to begin
Cut out sugary drinks, even if the descriptor says Diet, agave nectar, etc. Drink water!
Cut out packaged snacks. If the ingredient list has more than 3-4 items, or a Masters degree in organic chemistry is required to understand the ingredient list, time to eliminate it. Try to minimize snacking altogether, but if you must snack, select whole foods.
Try increasing the amount of proteins and healthy fats on your plate. This can be in the form of vegetables or animal protein. Rather than filling up on extra bread, pasta, increase your dark, green leafy vegetables rather than more starches.
Try to have your last meal each day no later than 7pm and have your first meal in the morning no earlier than 9-10 am. This will slowly introduce you to intermittent fasting. Once you get the hang of it, gradually push your window back, aiming for 11am or later.
During your fasting window, you may consume water, unsweetened tea, black coffee, and bone broth. While unsweetened tea, black coffee, and bone broth are not technically considered fasting, all of these are unlikely to cause a significant rise in insulin (more on the mechanism of fasting in the months to come).
Many baby steps equal huge gains!
One of the founders of modern medicine, Hippocrates wrote: "Everyone has a physician inside him or her; we just have to help it in its work. The natural healing force within each one of us is the greatest force in getting well. Our food should be our medicine. Our medicine should be our food. But to eat when you are sick is to feed your sickness."
This year, I challenge all of you, including myself, to let food be our medicine. To integrate stress reduction, relationship building, self love, and forgiveness into our lives. Don’t be discouraged about the weight you may need to lose. Find empowerment in the decision to improve your life and the lives of those around you. Additionally, even if you are at your goal weight, remember, we are learning more each day of the benefits of intermittent fasting. Even a fasting period of 12 hours can go a long ways to improving your overall health!
Follow more of Dr. Clark-Ganheart’s journey and health information @fastingworkgirl.com, Fasting Work Girl Chats, and www.fastingworkgirl.com
Disclaimer: The advice on this page is not meant to replace or represent medical advice. This is nutritional advice, which is NOT the same as medical advice. Prior to any weight loss endeavor, the consultation of an experienced health care provider is a must. As a general rule, the following individuals should not participate in fasting:
Diabetics-particularly those on insulin
Individuals with a history of eating disorders
Children under the age of 18
This list is not all encompassing; therefore, you should consult your healthcare provider prior to any new dietary or exercise approach.
Interaction through this blog’s associated social media accounts, podcasts, and other venues does not constitute a patient-physician relationship. Likewise, it does not constitute medical advice. By continuing to access this blog, or related resources, you acknowledge and agree that the content and contributors are not liable for your personal use of dietary and wellness advice found in our contents. You acknowledge our recommendation to consult your care provider prior to utilizing our nutritional advice.
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6) Volume 22, Issue 4Kajimura S, Spiegelman B, Seale P.Brown and Beige Fat: Physiological Roles beyond Heat Generation. Cell Metabolism. Volume 22, Issue 4, 6 October 2015, Pages 546-559
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