For the majority of our evolutionary history, we’ve lived in some kind of “feast or famine” state. Our hunter-gatherer ancestors had to search for available food sources and as a result, experienced periods of not eating. As we’ve evolved, our food sources have become more widely available but also more processed. Though there are many advantages to having an abundance of food, this accessibility along with foods that are often highly processed have contributed to an increase in chronic health conditions, including obesity, heart disease, diabetes, and cancer, among many other health conditions.
This is where sensible, intermittent fasting and eating clean foods play a significant role in our health and wellness. Intermittent fasting means allowing your body to break from food intake for set intervals of time. Though fasting is a therapeutic means for maintaining a healthy body weight and improving overall health and longevity, it’s a concept that is often misunderstood and confused with not eating enough, malnourishment, skipping meals, ignoring hunger, and/or overeating at the next meal. This beneficial practice isn’t about starving or gorging yourself; it’s simply about decreasing the frequency of caloric consumption to make yourself more metabolically flexible.
The Science Behind Fasting
The best way to think of your body’s metabolism is that it has two modes: feasting and fasting. When you feast, you’re eating and storing energy. When you’re fasting (not eating), you’re burning recently consumed calories and stored food energy.
When we consume carbohydrates, our bodies break them down into simple sugars for energy. Unused calories are stored as glycogen in the liver and as fat throughout the body. The pancreas plays an important part in this storage process by producing insulin, an essential hormone that facilitates blood sugar (glucose) moving into the cells. While in the feasting mode, insulin levels increase. When we stop consuming food and enter into the fasting mode, our insulin levels drop and become more sensitive and we burn the glycogen in our liver and peripheral fat for energy and fuel, which can lead to the therapeutic production of endogenous ketones.
The Benefits of Intermittent Fasting
Taking a break from eating allows your gut to rest, which ultimately allows your body to burn fat for fuel. By giving your gut a break, it also allows your immune system to concentrate on supporting other areas in the body outside of your gut. There are several ways in which to fast, but the goal is to include a window of time in which you do not consume food. Fasting has many positive mental and physical health benefits. It has been shown to:
- Lower insulin resistance (promotes insulin sensitivity)
- Improve blood sugar management
- Reduce stress on the pancreas
- Prevent, reverse, or slow Type II diabetes
- Enhance cognitive function
- Protect the brain against degenerative brain disorders such as Alzheimer’s and other neurological diseases
- Improve metabolic function and reduce visceral fat (abdominal fat) and body weight in overweight individuals
- Increase human growth hormone (HGH), which aids in metabolism, cell repair, and muscle growth while at the same time reducing body fat
- Lower LDL (bad cholesterol) and triglycerides
- Improve heart health and reduce risk of heart disease
- Decrease blood pressure levels
- Reduce hunger
- Eliminate sugar cravings
- Decrease chronic inflammation in the body
- Lower risk of cancer
- Improve immune system function
- Improve mitochondrial energy efficiency
- Balance hormone irregularities
- Increase longevity
WFP’s Take-Home Advice
Before trying any kind of fasting protocol, it is important to speak to a medical provider first for guidance. Individuals who are pregnant or breastfeeding, take certain medications like diabetes medications, have insulin sensitivity, have experienced any kind of eating disorder, or have other health conditions that require close nutritional monitoring should not fast. It is also important to note that children should not fast.
For a beginner’s guide to intermittent fasting, here are a few important take-home points that we believe are helpful and sustainable:
- Before you begin intermittent fasting, the first stage is to convert from an overly processed diet high in sugar and carbohydrates to a minimally-processed, low-sugar, low-carb diet. Be sure to eat whole foods like almonds, avocadoes, wild-caught salmon, grass-fed beef, and pasture-raised chicken. Avoid all processed foods and decrease your daily sugar intake to less than 30 grams. A clean diet is not only essential for fasting and facilitating the fat burning mode but also essential on a daily basis because eating clean contributes to your overall health and longevity.
- One to two days a week, restrict calorie intake to an 8-hour window so that you eat between 11:00 am to 7:00 pm or 12:00 pm to 8:00 pm. This simply means extending an overnight fast so that you are fasting for 16 hours.
- There are variations to the 16-hour fast that you might want to try: The 5:2 method involves eating your normal meals for 5 days of the week and for the other 2 non-consecutive days, consuming 500–600 calories; The Eat-Stop-Eat method involves fasting once or twice a week for 24-hours, which essentially means fasting from dinner one day to dinner the next day; The Warrior Diet is eating small amounts of raw fruits or vegetables during the day and then having one large meal at dinnertime; or simply skipping a meal one day for a spontaneous fast is another way to do intermittent fasting.
- Fasts that extend over 24 hours should only be done under the guidance of your medical provider.
- Nutrient-dense foods like fruits and vegetables help keep you full and decrease the urge to snack. Remember, snacking keeps your body in a constantly fed state. Avoid nibbling after dinner so that you don’t interrupt your fast.
- Drink purified filtered water to stay hydrated and to reduce food cravings. Begin each morning with 16-ounces of filtered water or natural spring water and continue to stay hydrated throughout the day. Drinking water, unsweetened tea, or black coffee during the long stretches of a fast is perfectly fine.
- Once your body begins to burn fat for fuel, you’ll notice a decrease in hunger and the craving for sugary foods.
- To learn more about the benefits of fasting and alternate ways to fast, read The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting by Dr. Fung.
- Try the Zero Fasting app for extra support; guidance with tracking your fasting protocol, goals, and health markers; and to tap into a library of educational content provided by health experts.
Sources and References:
Tello, M. (2020, February 10). Intermittent Fasting: Surprising Update. health.harvard.edu. Retrieved May 12, 2020 from https://www.health.harvard.edu/blog/intermittent-fasting-surprising-update-2018062914156
Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. (May 2018). sciencedirect.com. Retrieved May 12, 2020 from https://www.sciencedirect.com/science/article/pii/S1550413118302535
Intermittent Fasting: Live ‘Fast,’ Live Longer? (2019, December 26). hopkinsmedicine.org. Retrieved May 18, 2020 from https://www.hopkinsmedicine.org/news/newsroom/news-releases/intermittent-fasting-live-fast-live-longer
Truong, A. (2018, October 18). A fasting expert’s tip for making it to your next meal. qz.com. Retrieved May 12, 2020 from https://qz.com/quartzy/1428139/a-fasting-experts-tips-for-making-it-to-your-next-meal/
Mawer, R. (2019, September 23). 11 Ways to Boost Human Growth Hormone (HGH) Naturally. healthline.com.Retrieved June 19, 2020 from https://www.healthline.com/nutrition/11-ways-to-increase-hgh#1.
Gunnars, K. (2020, January 1). 6 Popular Ways to Do Intermittent Fasting. healthline.com. Retrieved August 13, 2020 from https://www.healthline.com/nutrition/6-ways-to-do-intermittent-fasting#section7