There are basically three types of IF: Time-restricted eating, prolonged fasting and the fasting mimicking diet. Time restricted eating or time-restricted feeding is daily IF and involves restricting the eating window to a certain number of hours each day. For example, you can eat between the hours of 12:00 noon and 6:00 pm for an 18-hour daily fast or between 10:00 AM and 8:00 PM for a 14-hour daily fast. The eating window can be whatever works best for you; the smaller the window the better and the more benefits you will reap. A 12-hour overnight fast is the bare minimum we should aim for every day. An ideal daily option is the 16 or 18-hour fast with an 8 or 6-hour eating window. This form of IF is done every day and is a great way to achieve and maintain a lean body, feel great, have increased focus and improved insulin sensitivity as well as allow the body to really get into its stored fat reserves.
Prolonged Fasting is a longer form of IF. If you fast for 24 to 48 plus hours, this is considered prolonged fasting. It is very useful for people with type 2 diabetes or obesity and will promote weight loss and restored insulin sensitivity. Prolonged fasting is especially beneficial for autophagy and everyone can benefit from this process of self-cleaning, detoxification and restoration. A 24 to 36-hour fast is something you can do as often as once or twice a week or as little as once a month and still experience benefits. A 36-hour fast basically involves not eating for one day. In this approach let’s say you eat dinner at 6:00 PM on Monday, you would not eat at all on Tuesday and then you would eat again after 6:00 AM on Wednesday.
If the thought of going completely without food doesn’t sound too appealing but you want the benefits of fasting, the fasting mimicking diet may be something to consider. Instead of abstaining from food completely like a traditional fast, you consume small amounts of food in a way that produces the therapeutic benefits of fasting. In this approach you eat about 40% of your normal daily calories which is about 600 to 800 calories a day for about five days using a non-inflammatory low-carb or ketogenic dietary approach. This allows the body to stay nourished with nutrients and electrolytes with less physical stress than normal fasting—but still receiving similar benefits. Long-term calorie restriction is harmful and will damage your metabolism, but IF and the fasting mimicking are safer and more effective. The fasting mimicking approach could be done quarterly or even once annually.
Getting started: It is important to be fat adapted before implementing a fasting schedule. By fat adapted, I mean that your body burns fat for fuel instead of sugar which allows you to go much longer between meals since fat is a more efficient fuel source. We become fat adapted by reducing the consumption of carbohydrates (mainly from sugar and refined carbohydrates) and increasing our consumption of healthy dietary fats. Once you become more fat adapted, you will be able to extend your fasting window from 12-hours to 16 or 18-hours daily. In order to fast regularly for 16-hours or more, you need to be fat adapted so that you are not hangry, irritable or end your fast in a binge. You may start with a 12 to 14-hour window and then each week try to move the window up an hour as you become fat adapted and eventually get to an 18-hour daily window. Many of us are fighting an addiction to and/or intense cravings for processed foods and sugar. For anyone with strong cravings and/or a poor diet, I recommend you start out by first cutting out the processed foods to end your cravings associated with foods that cause inflammation and then start IF once you have improved your diet and reduced your carbohydrate intake.
What can you drink during a fast? There are a number of acceptable and even encouraged beverages to consume during a fast, especially a prolonged fast as you will want to ensure you are refueling certain electrolytes if you are fasting for longer than 18-24 hours. One option for fasting is a water only fast. In a water only fast, you consume only water the entire fast. This is permissible for short-term fasting. Other permissible beverages include apple cider vinegar, bone broth, coffee, pickle juice, herbal or unsweet teas, fruit infused water (e.g. cucumber or lemon) and sparkling waters.
If you are doing an 18-hour+ prolonged fast you can add bone broth to your day for added nutrients and salt to ensure you don’t get dehydrated. Bone broth is also an excellent source of collagen. You can have coffee during a fast, but you cannot add any carbs or artificial sweeteners to it or it will break your fast. You can add MCT oil, coconut oil, or heavy cream, to your coffee for example, but nothing with any carbs. You may also consume pickle juice as another alternative to replenish sodium. During the FMD, which provides similar benefits to a prolonged fast, you would consume foods high in fat, low in carbs and protein for 5-7 days totaling about 600-800 calories per day. The FMD can be done as often as once every three months to experience the benefits of prolonged fasting or as little as once per year.
Tips for fasting:
- First and foremost, listen to your body. If you start feeling strange, don’t prolong your fast.
- If you have chronic health conditions, we recommend you first consult with your doctor especially before attempting a prolonged fast.
- If you have weak adrenals or are menstruating, you do not need to fast for longer than 12-14 hours per day.
- If you have type 2 diabetes you need to check your blood sugar often during your fast (at least morning and night). If you start to experience symptoms of low blood sugar, be sure to consume some carbs and do not attempt a prolonged fast unless under doctor’s supervision.
- Stay very hydrated. Drink plenty of water or other acceptable fluids.
Breaking your fast: When you finish a fast, it is important to eat fats and protein and very few carbs. This is especially true for a prolonged fast. You also don’t want to eat a huge meal following a prolonged fast. To break a prolonged fast, have a ¼ cup of nuts, ½ an avocado or a boiled egg. Then an hour or two later, you can have a normal sized meal.
One of my favorite benefits of fasting is the improved mental clarity and focus I experience. This is especially true in the morning when you wake up fasting. The reason for this is two-fold: One, we aren’t using our energy for digestion, which takes up a plethora of our energy every day. This freed up and extra available energy can be used for brain function, which is also a major user of our energy. Second, our brains are wired to look for food when we go extended periods without it, so in this case, if you don’t wake up and immediately eat breakfast, the brain is going to be laser focused (because back in the paleolithic times, we needed to be focused so we could find our next meal). In fact, the longer we go without food, the more focused you become as the brain senses the need to find food. Energy levels also increase, and many people report trouble sleeping after about a 36 to 48-hour fast. When we think about our evolution as a species this makes total sense. If our bodies were more tired and lethargic after a few days without food, we would have never survived as a species. Yet, it is just the opposite and we tend to have more energy and focus during a fast than when we are constantly digesting and metabolizing food.
Fasting is free and available to anyone anywhere. Give it a try and see how you feel! It is a great way to boost energy and mental clarity not to mention the numerous other benefits. Please reach out if you have questions or comments or would like to learn more.
In Health,
Dr. Moring
