My Personal 48-Hour Water Fast
– My Cancer Journey –

Dr. Al Danenberg Nutritional Periodontist

March 21, 2021 [printfriendly]



I wrote about my first 48-hour fast in 2017 – over a year before I was diagnosed with incurable bone marrow cancer. In that article, I discussed various methods of fasting and the benefits published in the medical literature. At that time, I did not do a strict “water fast”.

Now I am on my cancer journey. And fasting can play an important role along with my animal-based diet and my other Unconventional Cancer Protocols.

Just a couple of weeks ago, I finished my 48-hour water fast. Let me get into the details about fasting and then my personal experience this time around.



Always consult your doctor before attempting a 48-hour fast. Generally, there are those individuals who should not fast. They include:

  • Children
  • People with type 1 diabetes
  • People with low blood pressure
  • Those who are underweight or have a history of eating disorders
  • Women who are pregnant, breastfeeding, trying to conceive, or have a history of amenorrhea
  • Those taking certain medications such as insulin, blood pressure meds, blood thinners, and nonsteroidal anti-inflammatory drugs (NSAIDS)


Basic Benefits of Fasting[1]

Hippocrates was probably one of the first advocates of fasting for medical purposes. He recommended those who were sick to fast.

Research suggests 9 basic benefits we can derive from fasting:

  1. Cellular health: Fasting can assist in cellular repair and delay tissue aging, both of which will support overall longevity. In addition, many studies indicate that 48-hour fasting can improve cellular repair and increase cellular strength more than other fasting methods.
  2. Reduced inflammation: Fasting for more than 24 hours will reduce oxidative stress, which will reduce overall inflammation.
  3. Strengthened immune system: When animals in the wild get sick, they stop eating and focus on resting. This is a primal instinct which reduces stress on their internal system and enhances their immune system to fight infection.
  4. Improved insulin sensitivity and blood sugar levels: During a 24-hour fast, glycogen (the storage form of glucose) is depleted, and insulin levels are reduced. This allows your body to burn stored fat as fuel. Decreased insulin levels can improve insulin sensitivity and improve sugar control.
  5. Heart health: Several studies suggest that fasting may lower the risk of coronary heart disease and may help lower blood pressure, triglycerides and cholesterol levels.
  6. Enhanced brain function: Animal studies show that fasting could improve brain function, increase nerve cell synthesis and protect against neurodegenerative conditions (such as Alzheimer’s disease and Parkinson’s).
  7. Increased hormone secretion: Fasting can increase levels of human growth hormone (HGH), which plays a role in growth, metabolism, weight loss and muscle strength.
  8. Better digestion: Fasting gives the digestive system a break, improves the balance of bacteria in the gut, and increases bacterial diversity.
  9. Weight loss: Fasting may increase metabolism, help preserve muscle mass, and reduce body weight and body fat. A 48-hour fast, once or twice per month, will reduce your calorie intake by up to 8,000 calories per month, which can promote weight loss.


Cancer Benefits of Fasting[2],[3]

There are specific cancer benefits from fasting. These are related to the prevention of cancer, the decreased growth of cancer cells, and the enhancement of conventional cancer therapy.

Fasting …

  • Has only mild side effects, such as headaches, dizziness, nausea, and weakness
  • Leads to alterations in growth factors and in metabolite levels, creating an environment that will reduce the ability of cancer cells to adapt and survive
  • Decreases the level of critical nutrients thereby inhibiting cancer cells from proliferating at high rates
  • Sensitizes many types of cancer cells to chemotherapeutic medicines.
  • Forces healthy cells to enter a slow division and highly protected mode that protects them against the toxicity from anticancer drugs
  • Prevents detrimental and potentially life-threatening side effects and DNA damage from various cancer treatments


My Personal 48-Hour Water Fast

To summarize my way of eating: I am following a carnivore diet and stay in ketosis about 6 days a week. To know I am in ketosis, I measure my ketone levels with the Breath Ketone Monitor several times a day. After 6 days of ketosis, I cycle out of ketosis by consuming about 150 grams of carbs to stay metabolically flexible. My carbs generally consist of raw honey and various fruits. The day after my carb day, I return to eating my animal-based diet, which will include less than 20 grams of carbs per day.

I started my water fast on Monday, 3/8/21, at 7PM. That Monday was my “cycle day out of ketosis”.

The Table below shows the progression of my ketone levels starting from the time I started my fast at 7PM on Monday night until I broke my fast with dinner on Wednesday night at 7PM. I must tell you, I broke my fast with a delicious, juicy, medium-rare ribeye steak cooked to perfection in my Ninja Foodie Indoor Grill.

As you can see in the Table, my ketone levels were almost non-existent when I started my fast. They fell to 0.1 mmol/L by Tuesday morning at 8AM as my body was using the available glucose.

After my body digested the consumed carbs from Monday and used its glucose for fuel, my body began to mobilize glucose from the glycogen stores in the liver until they were depleted. The Table suggests that my liver glycogen was depleted around 4PM on Tuesday afternoon. That was when my ketone level rose to 0.5 mmol/L, which was about 21 hours after I started my fast.

Lipolysis in fat cells and ketone production by the liver then began in earnest. As I continued my water fast, my ketone levels increased to 2.0 mmol/L by the time I broke my fast on Wednesday night.

I easily could have gone another 24 hours. My hunger level was minimal, and my energy level was good.

All during the fast, I only drank mineral water or non-caffeinated herbal teas brewed in mineral water. I continued to drink my 8 ounces of SOLE water first thing in the morning on an empty stomach. SOLE helps hydration and provides 84 trace minerals.



Here is a Table that identifies the different ketone levels and their significance:


Overall Experience

The outcome of my 48-hour water fast was nothing short of amazing.

Previous to the fast, I was experiencing slight stomach discomfort – almost like reflux but not to the extent of burning. It was just an “uneasy feeling” in my gut. All during the fast and thereafter, my stomach distress completely disappeared. It has not come back.

Also, I noticed stable and even increased energy.

The only “hunger” sensation was around noon on Tuesday – about 17 hours after I started the fast. To curb that feeling, I drank herbal tea, which took care of the “hunger” feeling. As Tuesday progressed and until I broke the fast, I did not have a strong desire to eat food.

Because of the health benefits I discussed in this writing as well as my overall feeling during the fast, I will continue to do a 48-hour water fast once a month. Maybe next time I will try a 3-day fast. I plan to start my monthly fasts following my “carb cycle day”.







If you don’t want to miss out on new posts, sign up for my “Belly Bites” Newsletter HERE.