WARNING!
This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.
In the featured JJ Virgin Lifestyle Show podcast, I discuss my KetoFast protocol, which is the topic of my latest book by the same name. KetoFast is the term I coined to describe a protocol that combines three key strategies: a cyclical ketogenic diet, intermittent fasting and cyclical partial fasting.
In this interview, I describe how to implement the KetoFast approach, including the meal timing and the types and amounts of foods you should be adding to your plate.
“KetoFast” is the follow-up to my bestselling book “Fat for Fuel,” and I strongly recommend implementing the strategies laid out in “Fat for Fuel” first (which include daily intermittent fasting and cyclical nutritional ketosis), before you move on to “KetoFast,” in which you add partial fasting to everything you’re already doing.
Why I Wrote ‘KetoFast’
As I explain in this interview, the impetus behind “KetoFast” was two major realizations: First, that water-only fasting is a tremendously beneficial health intervention; and second, that while water-only fasting used to be an ideal strategy, the fact that modern man is so toxic makes it potentially dangerous to do extended water fasts for most.
We’re now surrounded by and exposed to some 80,000 chemicals in our environment, many of which are fat soluble, meaning they accumulate in your fat cells. Meanwhile, fasting effectively drives toxins out of fat cells, which can have devastating results if you’re severely toxic.
What’s more, since you’re not eating, you’re also not providing your body with the nutrients it needs to effectively neutralize and eliminate those released toxins.
My answer to this dilemma was to devise — based on the best scientific evidence I could find — a fasting program that mimics multiday water-only fasting, while supporting your detox pathways and minimizing the risks associated with toxicity.
The KetoFast protocol is also easier to comply with than multiday water fasting, and provides greater benefits because you’re able to do it more frequently. At most, you might do a five-day water fast 12 times a year (once a month). With the KetoFast protocol, you can do 42-hour fasts anywhere between 50 to 100 times a year.
The caveat is you need to have done at least a month of daily intermittent fasting and achieved nutritional ketosis as laid out in “Fat for Fuel” before you move on to KetoFasting. Once you’re metabolically flexible and can burn fat for fuel, the combination of cyclical nutritional ketosis and cyclical fasting is phenomenal for weight loss and optimizing your health and longevity.
Eating Too Frequently Creates Metabolic Dysfunction
In his book “Circadian Code: Lose Weight, Supercharge Your Energy and Sleep Well Every Night,” Satchidananda Panda, Ph.D., cites research showing that 90 percent of people eat across a span of 12 hours a day, and many across even longer timespans. This is a prescription for metabolic disaster, and will radically increase your risk for obesity and chronic degenerative disease over time.
Part of the problem is that when you eat throughout the day your body adapts to burning sugar as its primary fuel, which down-regulates enzymes that utilize and burn your stored fat. If you struggle to lose weight, this may well be a significant part of the problem — your body has simply lost the metabolic flexibility to burn fat for fuel.
The intermittent and partial fasting regimen described in “KetoFast” essentially mimics ancestral eating patterns, allowing your body to work optimally by allowing for periods of breakdown and cleanout, and periods of rebuilding and rejuvenation.
It’s particularly important to avoid snacking or eating a meal close to bedtime. You really want to stop eating at least three hours before you go to sleep, as feeding your body at a time when it does not need the energy fuels the creation of free radicals instead. Essentially, late-night snacking is a prescription for chronic disease and early death as it will impair your mitochondrial function.
Recent research1 shows men who eat supper at least two hours before bedtime have a 26% lower risk of prostate cancer, and women have a 16% lower risk of breast cancer than those who eat dinner closer to bedtime.2,3 This reduction in cancer risk makes sense when you consider the effect late-night eating has on your mitochondria.
Chronic inflammation is a hallmark of cancer, and by feeding your body late at night, the excess free radicals generated in your mitochondria will simply fuel that inflammation. Mitochondrial dysfunction in general has also been shown to be a central problem that allows cancer to occur. To learn more about this, see "The Metabolic Theory of Cancer and the Key to Cancer Prevention and Recovery."
Benefits of Fasting
The two primary benefits of fasting, in my view, are stem cell activation and autophagy. Stem cells play an important role in longevity as they are instrumental in repairing and rejuvenating your cells and tissues, while autophagy is your body’s innate cleanout process, by which damaged mitochondria, proteins and cells are digested and eliminated.
By upregulating autophagy and mitophagy (autophagy in your mitochondria)4 and boosting stem cells you will lower your risk of most diseases, including cancer5 and neurodegeneration.6
Nutrient composition is important here, and in the book, I provide details on how to optimize the autophagy and stem cell activation processes by eating certain foods (and avoiding others) at the right time. Aside from autophagy and stem cell activation, fasting is known to provide many other health benefits, including:7,8,9,10,11
Releasing ketones into your bloodstream, which help preserve brain function and protect against epileptic seizures, cognitive impairment12 and other neurodegenerative diseases |
Boosting production of brain-derived neurotrophic factor, which stimulates creation of new brain cells and triggers brain chemicals that protect against brain changes associated with Alzheimer’s and Parkinson’s disease13,14 |
Increasing growth hormone by as much as 1,300 percent in women and 2,000 percent in men,15 thereby promoting muscle development and vitality |
Lowering insulin and improving your insulin sensitivity; studies have shown intermittent fasting can both prevent and reverse Type 2 diabetes, which is rooted in insulin resistance16,17,18,19 |
Increasing levels of the neurotransmitter norepinephrine, which helps your body break down fat to be used as fuel and benefits your metabolism20,21,22 |
Boosting mitochondrial energy efficiency and biosynthesis |
Lowering oxidative stress and inflammation23 |
Improving circulating glucose24 and lipid levels |
Reducing blood pressure |
Improving metabolic efficiency and body composition, modulating levels of dangerous visceral fat and significantly reducing body weight in obese individuals |
Reproducing some of the cardiovascular benefits associated with exercise |
Regenerating the pancreas25 and improve pancreatic function, reversing diabetes |
Protecting against cardiovascular disease |
Reducing low-density lipoprotein and total cholesterol |
Improving immune function26 |
Synchronizing your body’s biological clocks27 |
Eliminating sugar cravings as your body adapts to burning fat instead of sugar |
Increasing longevity — There are a number of mechanisms contributing to this effect. Normalizing insulin sensitivity is a major one, but fasting also inhibits the mTOR pathway, which plays an important part in driving the aging process |
Summary of KetoFast Protocol
The following is a summary of my KetoFast protocol, which is, of course, expounded upon in my book. The first step is to compress your daily eating window to six to eight hours for at least four weeks, meaning you eat all of your calories for the day during those six to eight hours, and for the remaining 16 to 18 hours, you’re fasting. This is your base.
Once you’ve followed this intermittent fasting schedule for a month — at which point you’ll have restored your metabolic flexibility to burn fat for fuel — you can move into the second phase, which involves having a single reduced-calorie meal, ideally breakfast, followed by a 24-hour water-only fast, once or twice a week.
This meal will typically be somewhere between 300 and 500 calories. To determine how many calories you should have at this meal, first calculate your lean body mass by subtracting your percent body fat from 100. (So, if you have 20% body fat, you have 80% lean body mass.)
Then multiply that percentage (in this case, 0.8) by your current total body weight to get your lean body mass in pounds (or kilos). Next, multiply your lean body mass in pounds/kilos by 3.5. This is the number of calories you’ll want to eat for that meal.
Nutrient Ratios During KetoFasting
By eating just that one 300- to 500-calorie meal and then fasting for 24 hours, you essentially end up having eaten once in 42 hours. This will effectively allow your body to deplete the glycogen stores in your liver.
Even when you’re intermittently fasting for 16 to 18 hours, you still have plenty of glycogen left, but when you fast for 42 hours, glycogen will be completely depleted, sending autophagy soaring. And, you can do this twice a week! Now, what should these 300 to 500 calories consist of? Ideally:
• Carbs — Less than 10 grams of net carbohydrates (total carbs minus fiber) so as not to replete your glycogen stores. Primarily, your carbs would then be nonstarchy vegetables, seeds or nuts.
• Protein — Half of your personalized daily protein requirement. If you’re younger than 60, a general recommendation for your daily protein requirement would be 0.8 grams of protein per kilogram of lean body mass, or 0.5 grams of protein per pound of lean body mass. Let’s say your daily protein requirement is 80 grams. For this meal, you’d cut that in half to 40 grams.
The key here is not just lowering your overall protein intake but rather restricting your intake of branched-chain amino acids such as leucine, found primarily in meat and dairy products.
The reason you want to restrict branched-chain amino acids at this meal is because they activate mTOR and inhibit autophagy — essentially blocking the very cleanout process you’re trying to activate through fasting. You can learn more about mTOR and autophagy in my interview with Dr. Jason Fung.
An ideal form of protein to include in this meal is collagen, which provides great support for your connective tissue. Chlorella is another excellent protein you can include.
• Fat — The remainder of your calories come from healthy fats such as coconut oil, avocado, MCT oil, butter, olive oil and raw nuts.
After Your Fast, Feast!
The day after you’ve completed your 42-hour KetoFast is the perfect time to do hardcore strength training, and to load up on your protein. Immediately after is when you’ll want to eat that grass fed organic steak and/or whey protein, as now you’re in rebuilding mode, so you actually want and need to activate mTOR to build new muscle mass.
As mentioned, mTOR, governs growth and inhibits autophagy. In this way, KetoFasting allows you to really feast twice a week as well, which counters any feelings of deprivation you might have during fasting, and this may significantly improve adherence.