Breaking Down Myths About Fasting
“The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting,” co-authored with Jimmy Moore, details how to implement fasting and overcome some of the most common challenges that might arise, including persistent fears and myths associated with extended water fasting.
Dr. Fung’s new book is very helpful because it provides easy-to-follow basic guidelines for fasting, and reviews some of the most common myths and fears that keep many from implementing a fasting regimen.
A common myth is that fasting will lead to loss of muscle mass. Dr. Fung’s book clearly describes the process of protein catabolism, explaining how your body actually downregulates protein catabolism and upregulates growth hormones in response to fasting.
“If you follow the biochemistry, your body stores energy as glycogen in the liver, which is links or chains of sugar, and then it stores [it as] body fat.
During fasting, you start by burning off all the glycogen in the liver, which is all the sugar. There’s a point there where some of the excess amino acids in your body need to get burnt as well.
That’s where people say, ‘That’s where you’re burning muscle.’ That’s not actually what happens. The body never upregulates its protein catabolism. Never is it burning muscle; there’s a normal turnover that goes on.
There is a certain amount of protein that you need for a regular turnover. When you start fasting, that starts to go down and then fat oxidation goes way up. In essence, what you’ve done is you switched over from burning sugar to burning fat. Once you start burning fat, there’s almost an unlimited amount of calories there. You could go for days and days.
What’s interesting is that if you take a pound of fat, that’s roughly 3,500 calories. If you eat somewhere around 1,800 to 2,000 calories a day, it takes two full days of fasting to burn a single pound of fat, which is very surprising to people.
If you’re trying to lose 100 pounds, you could theoretically go 200 days of fasting just to burn all that fat … People worry about fasting for 24 hours. I’m like, ‘You could go 200 days.’ Then it’s like, ‘OK. Maybe it’s OK to go 24 hours without eating.'”
The ‘Starvation Mode’ Myth
Another common fear is that fasting equals starvation, not true.
Starvation is a forced situation that you have no control over whereas fasting is optional, you have complete control.
Many also believe they cannot or should not fast because it will send their body into “starvation mode” a situation where the body starts holding on to fat rather than burning it off, also, not true.
“What they are talking about is where the body’s metabolism starts to slow down so significantly that instead of burning 2,000 calories a day, your body might burn 1,000 calories a day.
In that case, even if you’re eating only 1,500 calories a day, for example, you’re going to gain your weight back. That’s actually what happens when you reduce your calories. We know that … as you cut your calorie intake, your calorie expenditure goes down as well.
Starvation mode actually is guaranteed if you just try and cut your calories. But what’s interesting is that fasting doesn’t do that. What happens during fasting is that … after four days of fasting, the basal metabolic rate is actually 10 percent higher than when you started.
The body has not shut down at all. In fact, what it’s done is it switched fuel sources. It switched from burning food to burning [body] fat. Once it’s burning [body] fat, it’s like, ‘Hey, there’s plenty of this stuff. Let’s burn our 2,000 calories’…”
This is also why fasting tends to increase energy opposed to leaving one feeling drained. If you are overweight and lethargic, fasting helps unlock all that energy already lodged in your body that you previously had no access to.
Fasting forces your body to start accessing those stores of energy, and once that happens, your body suddenly has a near unlimited supply of energy.
Fasting also helps improve other biochemical systems in your body. There is interplay of hormonal systems like the mammalian target of rapamycin (mTOR), AMPK, leptin and IGF-1, all of which are optimized in the right direction when fasting. It also improves your mitochondrial function, allowing your mitochondria to regenerate.
So, it is not just simply turning on an enzyme switch to burn fat; it’s a very complex process that upregulates in the direction of health.
Variations of Fasting
There are many ways to do an extended fast. Following are some variations:
•Water fasting — This is exactly what it sounds like: You do not eat; you only drink water, for several days in a row.
•Water plus non-caloric beverages — A slight variation on the water fast is to include other non-caloric beverages, such as herbal tea and coffee sans milk, sugar or other sweetener, including artificial non-caloric sweeteners.
•Bone broth variation — Another variation Dr, Fung often recommends for longer fasts is to allow the use of bone broth. In addition to healthy fats, bone broth also contains lots of protein, so it’s not really a true fast.
Still, in his clinical experience, many who take bone broth in addition to water, tea and coffee experience good results. “If you’re getting the results you want and it’s making it easier for you to stick to the program, then you should do it,” he says. “If you start getting bad results with fat fasting or bone broth fasting, you can go to classic water-only fast.”
•Fat fasting — Here, you allow healthy fats during the fast in addition to water and/or non-caloric beverages. While you probably would not eat a stick of butter, you could have bulletproof coffee (black coffee with butter, coconut oil or MCT oil), for example. Alternatively, you could add the fat to your tea.
Dietary fat produces a very minor insulin response, and since you’re keeping your insulin levels low, you’re still getting most of the benefits of fasting even though you’re consuming plenty of calories. Adding healthy fats such as butter, coconut oil, MCT oil and avocado can make the fasting experience a lot easier. “Lots of people have done very well with this sort of fat fast,” Dr. Fung notes, adding “Anything that increases your probability of success I’m all for.”
It contains beta-lapachone, which upregulates NAD+, an important electron transfer mechanism and mitochondrial signaling molecule. To that, I add some coconut oil, MCT C8 oil, butter and a little stevia. It contains about 400 or 500 calories per cup.
Part of the Key is to avoid protein to inhibit mTOR.
While the level of protein at which you will counteract the benefits of fasting is individual, Dr. Fung believes you will likely see results as long as you stay below 10 or 20 grams of protein per day.
As a reminder, protein raises your insulin, although not to the same degree as net carbs do. Excess protein is likely more damaging metabolically than excess carbs.
“I was looking at some data recently where they graphed where your blood sugars are in relation to where your ketones are. Ketones start to go up as your blood glucose falls [but] that slope changes in different people,” Fung says. “If you look at, for instance, type 2 diabetics, they have a very steep slope. That is their blood glucose — even as it falls — ketones don’t go up.
That’s probably why they feel like crap, because they’re not getting the ketones. The blood glucose is going down, which it should, but the body should be producing ketones for their fuel for the brain, but it’s not.
In those cases, some of the fat bombs, some of the exogenous ketones, may actually make it a lot easier for people to get through that. As your body becomes [fat] adapted, which can take two weeks to a month, that shouldn’t happen anymore …
If you have never fasted and you do a three-day fast, you may feel pretty lousy. We tell people to expect that. You can either continue or you can take a break and let your body become more adapted to it.”
The same applies to hunger pangs, which tend to kick in the hardest on the 2nd day of a fast. By the 5th or 6th day hunger practically disappears.
Fasting Is Safe, You Can Do It
Barring you fall into any of the Dr. Fung’s contraindicated groups, fasting is safe. Even very sick patients have done it and improved their health in the process. Dr. Fung has been using water fasting and variations thereof in his clinical practice for the past 5 years.
In that time, he has placed well over 1,000 patients on various fasting regimens. Some do tremendously well. One man in his 50’s had struggled with diabetes for 20 years. Within 2 weeks, he was able to quit taking all of his diabetes medications. His blood sugar was back to normal without them.
“Then his sister saw he was doing really well. She comes in. She’s on three pills for diabetes. Within a month, we took her off all three. She takes herself off the other two blood pressure medications and cholesterol pills. We took her off six medications in a month and a half. That’s amazing. Obviously, they did very well. But that just goes to show you what can happen when you try some of these things,” Fung says.
“Initially, there was a huge amount of skepticism. Everybody thought I was crazy. But now I have so much support from my own local area because everybody has seen the results. I have lots of doctors at my hospital who are doing it. Once they see it themselves, they’re like … ‘This is amazing.’ They start referring me patients and say, ‘I want these benefits for my patients.’
Because they know they can’t provide that kind of supportive environment that we can provide; that we set up in our clinic, where we kind of anticipate their problems, give them the support, the online resources, the books … to be able to do it successfully.
That’s the key: To have the acceptance. There are so many naysayers out there who say, ‘You shouldn’t do this. You can’t do this.’ But within my own local area now, we’re really seeing a lot of strong support for this, because it’s undeniable.”
Dr. Jason Fung has written an excellent book on how to implement extended fasting. If you are overweight “The Complete Guide to Fasting” will really guide you through the process. Most likely, unless you are taking medications, you will not require a professional healthcare consultant help you. Yes, it nice to have, but you can likely manage on your own.
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