I want to share with you the benefits of a practice that’s been around for a long time, but isn’t always talked about - fasting. It’s a topic that can be complicated and even controversial at times, and it’s something that you should definitely discuss with your medical team before starting. After all, each cancer journey is unique and your healing is not “one size fits all.”
First, let’s talk about the basics! Fasting in its most simple terms is abstaining from caloric intake for a prolonged period of time. It’s used in many religious practices, and it’s been a part of human development and evolution because there were times when food just wasn’t easy to come by. Our bodies evolved over the centuries knowing how to survive without consistent food sources. Isn’t that amazing?
Thanks to modern research, we’re learning so much about the physiological processes and changes that happen during periods of fasting, and how beneficial it can actually be. There are also several different approaches that you can take to fasting.
24 hour fasting: any 24 hour period of time with no calorie intake, and only water.
Reduced calorie fasting: limiting your caloric intake to 1/3 of your normal calories (typically 550 - 700 calories)
5-2 day fasting: picking two non-consecutive days within a week to completely fast or restrict your calorie intake
Time-restricted or intermittent fasting: restricting your eating window to certain hours of the day. Example: 16/8 - fasting for 16 hours, and eating during the 8 hour window. You could also fast for 14 hours, and eat during a 10 hour window. Anything over 12 hours can start the health benefits of fasting.
What’s important in all of this though is that you listen to YOUR body. Everyone is different, and some people can’t fast for 18 hours at a time - it just doesn’t work for their systems. I’ve found Intuitive Fasting by Dr. Will Cole really helpful when it comes to fasting. His book lays out a lot of different approaches to fasting, and walks you through a way of incorporating all of them. This resource is so helpful because you can really see what works best for your body. He also talks about the benefits of cycling through different approaches which can help achieve and maintain metabolic flexibility in your body, and that’s so important for long term wellness.
So now let’s talk about the benefits of fasting! After all, we’re used to being in a culture that’s always eating. There was even an idea not long ago that fasting would slow down metabolic function, and that smaller frequent meals were best. Now we’re learning that this just isn’t the case at all. Think about how long it takes to digest food - if your body is constantly trying to digest what you’re eating, then it’s not going to be allowed to start the cascade of hormone and molecular shifts that lead to cellular regeneration and detoxification because your body is working so hard on the digestive process.
Fasting also has a tremendous impact on regulating your insulin levels. Your blood levels of insulin drop significantly during a fast, and this actually helps facilitate fat burning. We know that insulin has been linked to a lot of inflammatory responses in our body, while fasting, on the other hand, is linked to improved insulin sensitivity. After all, we have an epidemic of insulin resistance right now in our country, which is ultimately what leads to the development of diabetes.
Studies also show that fasting impacts leptin resistance. Leptin is a hormone that's produced in your adipose, or fat cells. The primary function of leptin is to tell your brain to use your fat stores for energy. This is another key to metabolic flexibility. During leptin resistance, the hypothalamus of your brain stops recognizing leptin signals. As a result, the brain doesn't perceive that the body has enough food. In fact, it actually turns on a whole cascade of signals that tell your body that it's starving, and therefore everything you eat goes straight into fat storage. It creates this vicious negative cycle of storing fat instead of using it for energy. Fasting is a really powerful means to break that leptin resistance and to stop this downward spiral.
Fasting also has an impact on human growth hormone levels, which are dramatically increased during fasting. This helps facilitate fat burning and muscle gain. Human growth hormone also has numerous other anti-aging and anti-inflammatory benefits, including cellular repair. Again, if your body is doing all the work to digest, it can't do the cleanup or housekeeping from a cellular standpoint. When your body is able to rest from the toll of digestion, it can go to work on that cellular repair and detox process. One of the aspects that's been studied specifically during fasting shows that our body is able to encourage a process called autophagy. This is the removal of waste products and toxic buildup from our bodies at the cellular level.
The last benefit of fasting we'll touch on is a reduction in oxidative stress. Several studies have shown that intermittent fasting can enhance the body's resistance to oxidative stress, which we know is a big driver for the development of disease. Studies have actually shown that intermittent fasting can help fight inflammation and other common drivers for many disease processes.
So how do the health benefits of fasting translate specifically to cancer? Well, studies have demonstrated that fasting can help with cancer outcomes and improve the efficacy and tolerance of cancer treatment. It's important to point out that there is still a need for larger studies to explore the various impacts of fasting on cancer and cancer treatment. However, one physician, Dr Jason Fung, MD, has thoroughly explored the research of fasting and cancer. In this video, he discusses the benefits of fasting for 24 hours before chemotherapy, and how this process can put you into a regenerative mode. In other words, you don't sustain as much damage from the chemotherapy, and the cancer cells specifically to receive more of the effects from the chemotherapy.. This allows the chemotherapy to be better tolerated, and more effective in treating the cancer. He has a book called The Cancer Code and he’s been featured on a lot of podcasts discussing this research.
As with all of the topics that I cover, please make sure that you're seeking the advice of your medical team. We know that there's just not any one approach or silver bullet to improving cancer outcomes. My main goal is to introduce various tools that I know can have an impact on improving your cancer journey and allow you to decide what is best for you.