Metabolic diseases are one of modern medicine’s biggest foes. Chronic medical conditions such as type 2 diabetes, hypertension, high cholesterol, obesity and fatty liver are huge health hurdles that cost the system and patients a significant amount of money. When done correctly, fasting is a very effective tool to tackle these issues. It can even be helpful in slowing the aging process, preventing cancer and improving heart health.
Fasting has been going on since the beginning of time. However, in the past it was often done out of necessity due to lack of available food. Religious fasting is a common occurrence as well. More recently fasting has become a medical tool to treat so many conditions and promote overall wellness. There has not been much press abut fasting though, and it seems many Americans have the misconception that fasting is unhealthy. It is no wonder that people assume this. Since the 1970s, Americans have been told to eat small, frequent meals to be healthy.
What happens when we eat? After we eat food, we either use the food for immediate energy, or we store it. This occurs through insulin release. Insulin helps the digested food to be converted to energy. It also helps excess energy to be stored. This can be done via sugar storage (glycogen) in the liver or fat storage in the liver. The more frequently we eat, the more times we release insulin. (And the more fat we store!)
What happens when we fast? When we don’t eat food, there is no need for insulin release to help our bodies store the energy. Instead, our bodies will burn the stored sugar from the liver by turning glycogen into glucose, or we burn excess body fat for energy. The glycogen stores in the body can typically last about 24-48 hours. After that time, the body relies on energy from fat breakdown (lipolysis). All in all, insulin is very necessary for life, but like everything else, you can definitely get too much of a good thing. For ideal health, it is best to keep insulin release low.
Fasting has many advantages. It improves mental clarity, induces fat loss and improves blood sugar levels. It can be helpful to improve cholesterol levels and fat burning. Fasting improves insulin sensitivity and helps to prevent diabetes. It also extends life, reverses the aging process and helps to decrease levels of inflammation. One of the biggest advantages is that it is simple and cheap! There is no confusion about which foods are good to eat when you are not eating. Fasting can be done anywhere or any time.
While fasting is a great tool to promote health and wellness as well as treat many of the modern medical problems, there are a few people who should not fast. Anyone who is undernourished or malnourished should not fast. Children should not fast. In addition, pregnant or breastfeeding women should not fast. If you are interested in fasting, ask your primary care physician if it is safe for you. There are definitely some cautions regarding certain medical conditions and medications that can make fasting difficult or unsafe. It could worsen gout. Diabetics taking insulin or certain diabetic medications should only fast after getting physician’s approval. Fasting can worsen severe gastroesophageal reflux in the short term while it would be expected to improve reflux in the long term.
Intermittent fasting is simply periods of fasting that occur between periods of eating. It is typically the easiest way to begin fasting. This is something that can be done for any amount of time, but a good starting point is to do a short 12 hour fast. This would mean that you would eat, for example, from 7 am to 7 pm and then not eat anything after dinner until breakfast. Even this short fast can decrease the insulin levels and improve health. However, for the real benefits of fasting, a bit longer fast is needed. A sixteen hour fast offers more benefits and is fairly easy to work into a normal life. This could be done a number of ways, including beginning a fast at 7 pm after dinner and then skipping breakfast. This could also be done by eating breakfast and lunch and then missing dinner.
Longer fasts can be more difficult but they offer some additional benefits. A 24 hour fast involves fasting from breakfast to breakfast or dinner to dinner, etc. This type of fasting still allows for eating a meal with family and it can make work days more productive. You may have heard people talking about OMAD. This is another term for a 24 hour fast — One Meal A Day. For many people, this can be incorporated into a week once or twice fairly easily. Longer fasts can definitely be done, but they are not recommended for beginners.
There are many different opinions about what food and drink is allowed on fasting days. Unless you are fasting for religious reasons, there is no reason to completely fast without any intake at all. Drinking water is absolutely advised. Generally, non caloric beverages are encouraged. This includes coffee and tea. Some people drink diet soda and similar beverages but it is best if that is not done. The goal of fasting is to limit insulin release though, so anything that doesn’t trigger insulin release is considered acceptable. Since fat doesn’t typically trigger insulin release, some people will choose to add some coconut oil or cream to their coffee or tea.
While fasting has many health benefits, it cannot be a substitute for a healthy diet. It is a tool in the arsenal for those looking to improve their health status. Ideally it would be done with a whole food diet without processed foods. Fasting should not be difficult. If it feels hard, start with a shorter fast. Slowly work into it. Do it one day a week and gradually work up to 2-3 days. Do what works for you. Fasting is flexible and should be low stress. Have more questions? Send me a message or check out The Complete Guide to Fasting by Dr. Jason Fung and Jimmy Moore.