Fasting To Boost Cancer Recovery

I spend most of my time teaching people what foods to eat more of, in order to help their body heal from cancer. But sometimes it makes sense to not eat at all!

The 4 Most Toxic Foods To Avoid During Cancer Recovery

This FREE Guide will help you take the First Step in helping your body heal!
By knowing what foods will feed your cancer vs. slow it down, you and your family can begin to take control again.


Where should I send your FREE Guide?

When you’re pulling together an Integrative Cancer Care Plan, intermittent fasting should definitely be a tool you consider. There are many, many benefits to fasting. So much so, that I actually believe it could be one of the most important tools to add to your healing tool-kit. You can read more about all the different benefits of fasting plus how to get started here: Fasting: The Best Tool To Improving Health.

But today I want to dive deeper into how fasting can specifically benefit your cancer recovery. Fasting has been shown to slow and even stop cancer progression. It boosts the immune system, lowers insulin and blood sugar, improves insulin sensitivity, lowers inflammation, and reduces fat in the liver. All of these factors are incredibly important to the development and spread of cancer.

It has even been shown to improve the effectiveness of chemotherapy & radiation while reducing side effects!! It almost sounds too good to be true, right?! Fasting may just be the missing magic pill to your treatment plan. Let’s take a look at the research.

Nature’s Immunotherapy

When fasted, your cells initiate cellular repair processes. This includes autophagy, where cells digest and remove old and dysfunctional proteins that build up inside cells. This also includes targeting and removing viruses, parasites, and other microbes from the body.

Not only does fasting help to remove weak and damaged cells, it also boosts stem cell production. As soon as you start eating again the stem cells form new, stronger white cells. This process was first documented by Dr. Valter Longo at the University of Southern California.

Both pre-clinical and clinical studies have also shown the ability of fasting to lower insulin, insulin-like growth factor, and inflammation markers in the blood. In longevity studies, fasting has also been shown to change gene expression that influences disease protection.

Boosting Treatment

Now as if all the above wasn’t enough to get you fired up to start fasting, there’s more!! Fasting provides 3 specific benefits when added to traditional cancer treatments, like chemotherapy or radiation.

  1. Differential Stress Resistance
  2. Lower Inflammation
  3. Lower Blood Sugar

First, let’s talk about differential stress resistance. In a normal, non-fasting, state, healthy cells grow and reproduce. But during fasting, their energy shifts toward repair and protection. They slow down, preserve their energy, and switch to ketones (fatty acids) as their primary fuel source. Cancer cells, thankfully, do not respond as quickly to the external stress of energy restriction. What this means is that while healthy cells are now protected, with less drug uptake during treatment, cancer cells are no longer being fueled and become more vulnerable.

Result = improved treatment effectiveness (aka more cancer cell death) + less side effects

The other ways fasting can be beneficial is by lowering inflammation and blood sugar. Both chemotherapy & radiation increase inflammation in the body and some chemotherapy medications also increase blood sugar levels. Both of these consequences can interfere with the effectiveness of treatment and cause more side effects. By better controlling these factors you feel better and help the treatment work better!

The next natural question, of course, is how long do you need to fast for?

The research shows that between 48-72 hours before treatment provides the best results; meaning less uptake of medication by healthy cells (less side effects) and more uptake of medication by cancer cells (more cancer cell death). Therefore my general fasting recommendation is as follows:

2-3 Days Before Treatment + Day of Treatment + 1 Day After Treatment → Total of 4-5 days every treatment cycle

You can read more about the research regarding Fasting & Cancer here: (1, 2, 3, 4, 5, 6, 7)

Is It Safe?

Research has confirmed that fasting is safe in humans, and likely protective. Even water-only fasting combined with chemotherapy has been shown to be safe.

That said, there are times when fasting is not recommended. For patients who are already underweight or malnourished I would not recommend adding fasting to their protocol.

It’s also important to take into consideration a patient’s risk for cachexia (a “wasting” disorder that causes extreme weight & muscle loss) as well as the type of cancer; some cancers are hypermetabolic, which means they use a lot of energy and the patient is at a higher risk for weight loss.

As with any integrative cancer therapy, I would always recommend that you work with a qualified provider to make sure it’s appropriate and safe for you.

Adding Fasting To Your Routine

Okay, so assuming you’re fired up, and feel like you’re a good fit for fasting, there are definitely some safe ways you can start.

Step 1. Extend Your Nightly Fast

The first step towards integrating fasting into your routine is to start with a 12-14 hour nightly fast. If you eat dinner by 7pm then you wouldn’t eat breakfast until 7-9am the next day. This allows adequate time for your body to move through digestion and all the steps of detoxification before you start eating again. This can safely be done every night.

Step 2. Add Intermittent Fasting

The next step is to extend your fasting period to 16-18 hours. With new research coming out about the importance of timing your fasts to your circadian rhythm, rather than fasting through breakfast, I would encourage you to try fasting during the evening.

Here are 3 examples of how this could look:

16 Hour Fast

Breakfast: 7am

Lunch: 11am

Dinner: 3pm

~ nothing except fluids until the next day at 7am

18 Hour Fast (with 3 meals)

Breakfast: 7am

Lunch: 11am

Dinner: 2pm

~nothing except fluids until the next day at 8am

18 Hour Fast (with 2 meals)

Breakfast: 8-9am

Lunch/Dinner: 1-2pm

~nothing except fluids until the next day at 7-8am

Either of these options could safely be added 2-3 times a week. It’s very important that you keep your hydration up while fasting.

Fluid Goals: The goal should be to drink between 8-12 oz every hour you are awake and fasting. You can mix it up with water, herbal tea, green tea, black tea, coffee, or broth.

For the following two steps I would only advise you pursue them with the support of a practitioner.

Step 3. Add Extended Regenerative Fasting

A 3-5 Day Fast (72-120 hour) several times a year would be the best way to regenerate your immune system, boost cellular repair, and promote longevity. Same as above, you would fill your body with fluids during this time, rather than food. You would need to plan in time to take it easy, sleep more, and rest when you feel tired. Most people are surprised to find that they actually feel good and sometimes with even more energy after the first 24-48 hours. But you want to make sure you set the time aside so you can give your body what it needs during this time.

Step 4. Timed Fasting With Treatment

As I discussed above, this fasting protocol would match the timing of your treatments; ideally 2-3 days before the day of treatment plus 1 day following treatment. This is assuming your treatment protocol includes cycles of 1-day treatments. Again, most of my clients are surprised that this isn’t that hard to do. But I would suggest experimenting a bit with intermittent fasting first to boost your confidence going into the extended fast. If your treatment plan includes more than 1-day of treatment than the fasting would need to be adjusted accordingly. And, I’ll say it again, only do this under the supervision and guidance of a provider.

Take Home Message

Although most of the research up until now has been pre-clinical (cell & animal models), we are starting to see more and more human studies and there are several clinical trials currently underway. The results so far are promising and the safety data is also really good. The potential benefits are vast:

  • Reduced blood sugar production and insulin levels
  • Lowered inflammation
  • Boosted stem cells to help regenerate the immune system
  • Targeted cell repair plus removal of damaged cells & microbial infections
  • Protection of healthy cells during chemotherapy and radiation
  • Improved treatment effectiveness
  • Gene changes to enhance longevity and disease protection

Because of all of these factors, I would definitely encourage you to consider including fasting in your integrative treatment plan. Start with Steps 1 & 2 and see how it feels.

Then when you’re ready to take it further, contact me to schedule a FREE 20-min “Planning Session” where we will review your diet, your lifestyle, your cancer treatment plan, and begin to map out your best recovery strategy…including fasting.

Click here to book a 20-minute “Cancer Recovery Planning Session”.

The 4 Most Toxic Foods To Avoid During Cancer Recovery

This FREE Guide will help you take the First Step in helping your body heal!
By knowing what foods will feed your cancer vs. slow it down, you and your family can begin to take control again.


Where should I send your FREE Guide?