Bet you can't fast

People who continue to consume the world's most destructive grain, i.e., wheat, can rarely endure fasting--not eating for an extended period--except by mustering up monumental willpower. That's because wheat is a powerful appetite stimulant through its 2-hour cycle of exaggerated glycemia followed by a glucose low, along with its addictive exorphin effect. Wheat elimination is therefore an important first step towards allowing you to consider fasting.

Why fast? I regard fasting as among the most underappreciated and underutilized strategies for health.

In its purest form, fasting means eating nothing while maintaining hydration with water alone. (Inadequate hydration is the most common reason for failing, often experienced as nausea or lightheadedness.) You can fast for as briefly as 15 hours or as long as several weeks (though I tell people that any more than 5 days and supervision is required, as electrolyte distortions like dangerously low magnesium levels can develop).

Among its many physiological benefits, fasting can:

  • Reduce blood pressure. The blood pressure reducing effect can be so substantial that I usually have people hold some blood pressure medications, especially ACE inhibitors and ARB agents, during the fast since blood pressure will drop to normal even without the drugs. (A fascinating phenomenon all by itself.)

  • Reduce visceral fat, i.e., the fat that releases inflammatory mediators and generates resistance to insulin.

  • Reduce inflammatory measures

  • Reduce liver output of VLDL that cascades into reduced small LDL, improved HDL "architecture," and improved insulin responsiveness. (The opposite of fasting is "grazing," the ridiculous strategy advocated by many dietitians to control weight. Grazing, or eating small meals every two hours, is incredibly destructive for the opposite reason: flagrant provocation of VLDL production.)

  • Accelerate weight loss. One pound per day is typical.

Beyond this, fasting also achieves unique subjective benefits, including reduced appetite upon resumption of eating. You will find that as single boiled egg or a few slices of cucumber, for example, rapidly generate a feeling of fullness and satisfaction. Most people also experience greater appreciation of food--the sensory experience of eating is heightened and your sense of texture, flavors, sweetness, sourness, etc. are magnified.

After decades of the sense-deadening effects of processed foods--over-sugared, over-salted, reheated, dehydrated then just-add-water foods--fasting reawakens your appreciation for simple, real food. On breaking one of my fasts, I had a slice of green pepper. Despite its simplicity, it was a veritable feast of flavors and textures. Just a few more bites and I was full and satisfied.

Once you've fasted, I believe that you will see why it is often practiced as part of religious ritual. It has an almost spiritual effect.

More on fasting to come . . .

Comments (28) -

  • Soul

    5/26/2011 12:43:19 PM |

    Thought this interesting, talking about wheat, saw yesterday on the news that NBC is hosting "health week" this week.  It is sponsored by General Mills, if I remember correctly, with emphasis on the importance of eating whole wheat for good health.

  • Gene K

    5/26/2011 3:56:41 PM |

    1. Should I continue to take all my supplements and medications during fasting, e.g. Niacin, or does it depend?
    2. If upon fasting, satiety comes after eating a small amount of food, how do I make sure my nutrition is sufficient to maintain the muscle mass? How do you combine fasting and exercise?

  • Joe

    5/26/2011 4:52:26 PM |

    Gene, my guess is that you can't. Or shouldn't. But then you're probably not going to fast for more than a few days at most, so going without exercise for a few days is probably not going to cost you any muscle mass.

    I would also think it's probably okay to take your usual supplements, too.  Medicines may be a problem, depending on what they are.  People with serious health issues probably should avoid fasting altogether, unless under the close supervision of his or her doctor.

    I'm interested in hearing what Dr. Davis has to say regarding fasting.  Hurry up doc!


  • Kent

    5/26/2011 5:22:21 PM |

    Is it true that fasting can also improve LP(a)?

  • Steve Cooksey

    5/26/2011 8:27:45 PM |

    Agreed Dr. Davis.

    I am a big fan of intermittent fasting.... looking forward to more posts.

  • Rob O.

    5/26/2011 8:54:14 PM |

    I've had a similar experience to your post-fast feeling upon eating by doing a 2 or 3 day liquid-only diet that's heavy on water and includes a large protein shake each day.  It's as though you have to periodically remind the part of your brain that listens to the stomach what "full" means.

    Like the others, I'm very interested in what the doc has to say in the next article in this series!

  • Paul

    5/26/2011 9:28:09 PM |

    To what extent does a person with impaired adrenal and/or thyroid function need to be careful when fasting or low-carbing?

  • Mark. Gooley

    5/26/2011 10:24:13 PM |

    Type 1 diabetic for 40 years, and nowadays I eat about a thousand-calorie high-fat breakfast and a similar dinner.  I rarely eat lunch, and skipping breakfast (simply omit the pre-meal shot of insulin) as well is usually not a big deal any more: I do it occasionally.  Control of blood sugar is much easier now, and Hb A1c around 6 rather than over 10: still room for improvement.  When I was eating skimmed milk with Grape-Nuts or Uncle Sam (whole wheat flakes with whole flaxseed) for breakfast I would have blood sugars as high as 300 by mid-morning and a powerful hunger by lunchtime.  Whatever benefits fasting may have, I find it a lot easier now than it once was, and plan to try it more often, as I'm still overweight.

  • Gene K

    5/27/2011 3:07:21 AM |

    Is snacking on raw green vegetables between meals also considered grazing?

  • JLL

    5/27/2011 11:22:09 AM |

    I experimented with intermittent fasting (IF) for a little over a year. I first got interested in IF through calorie restriction (CR) -- there were a couple papers suggesting that you could extend lifespan through IF without the CR, which seemed like the perfect combination.

    These papers are still quoted on many blogs, but I doubt many have actually read them, since none of them actually show you can increase lifespan without restricting calories. See this post for a more detailed analysis:

    Anyhow, I still think there might be benefits for doing intermittent fasting -- though I've also seen some studies showing it might have negative effects as well -- and certainly it seems pretty good for weight loss. When I was on a high-fat, low-carb diet and fasting for 24 hours, then eating for 24 hours, I was the leanest I'd ever been. And that was without trying or counting calories:

    And one more shameless plug, some tips for those who have trouble going without food for 24 hours (or more):

    Personally, I never went for several days without food. I'm not sure it's needed for weight loss anyway, although it might have other health benefits.

    - JLL

  • Dr. William Davis

    5/27/2011 11:40:28 AM |

    Hi, Gene--

    Green vegetables have no discernible postprandial chylomicron/VLDL consequence and is the exception. I'd consider that safe "grazing."

    We usually hold niacin during a fast due to the fluid struggles, which can magnify the hot "flush." We usually continue the other supplements, however.

  • Dr. William Davis

    5/27/2011 11:41:49 AM |

    Hi, Paul--

    If not yet corrected, I don't think it would be a good time to fast, since you could feel pretty crumby during your fast.

    Fasting should be a positive experience, not something to endure. I'd wait until these issues are corrected.

  • Dr. William Davis

    5/27/2011 11:45:56 AM |

    Hi, JLL--

    Agreed. In fact, I believe that the greatest benefits of intermittent fasting are the subjective benefits of reawakened taste and appreciation of food, rather than the physiologic benefits. Nonetheless, it makes sense that, since atherosclerosis and arterial dysfunction are to a large degree postprandial phenomena, prolonged "no-prandial" periods might facilitate arterial health.

  • Carl N

    5/27/2011 1:26:16 PM |

    Is it possible that current wheat strains have been selected or genetically engineered to be addictive?

  • Steve O

    5/27/2011 4:36:54 PM |

    Today's Urban Dictionary Word of the Day: Carb Coma -- The sleepy feeling after eating a large meal comprised chiefly of carbohydrates, whether in the form of rice, noodles, bread or dough.  "Dude, I was totally dozing at the office after that giant serving of chow mein for lunch. Total carb coma."

  • Curtis

    5/27/2011 6:12:12 PM |

    I have been following Fast-5 for three years, and quickly got down to a healthy weight. I'm 58 years old and lost 25 lbs to get down to 160lb (5'-11''), and a reasonable BMI. I fast daily for 19 to 21 hours with absolutely no effort required - it is just the way I live now. During this whole time I have made no effort to restrict wheat in any way. I don't eat a lot of wheat and I don't eat it every day, but on the day after pigging out on pizza I have no trouble with my fasting. There's your black swan.

  • Might-o'chondri-AL

    5/28/2011 12:28:56 AM |

    Ketone metabolites from Beta oxidation of fatty acid, B-hydroxy-butyrate , increase when fasting;  these metabolites act on visceral fat receptor HM74A. The result is upregulation of the anti-inflammatory  molecule adiponectin;  it (adiponectin)  also keeps less glycerols  (think of tri-glyceride group).

    The increased adiponectin upshot is the white visceral adipose (not subcutaneous fat) does less lypo-lysis (fat cleaving) and there is a reduced level of free fatty acids going into circulation.  This relief, from excessive "freed" fatty acids ,  permits the response to insulin to improve (ie: sensitivity to insulin better) when go back to eating;  and the longer the fast went on for  the longer the boost of circulating adipinectins stays  around   than before.

    Low serum adiponectin levels are common in the obese, hyper-glycaemic,  diabetic;  individuals with  hyper-triglycerides, coronary artery disease (and often even the children of  hyper-tensives.  Metabolic syndrome tends to low adiponectin and concurrent high levesls of circulating triglycerides.

    The  actual anti-inflammatory action of adiponectin is a major  part of why the fast makes the body feel so much better;  the digestive  organ rest is given too much focus.   Many individuals report  " pain gone"  from diets  that favor more ketone derived energy
    production (like low carb,  calorie restriction &/or  ferments for gut bacteria) ;  because,  there too, the metabolite Beta hydroxy-butyrate is instigating more circulating adiponectin that  then stymies pro-inflammatory cytokines.

  • Dr. William Davis

    5/28/2011 3:08:20 PM |

    Hi, Might--

    You make a crucial point that, I believe, explains much of the benefits to fasting: via improvements in cytokine levels and tissue responsiveness, especially adiponectin.


  • Dr. William Davis

    5/28/2011 3:09:26 PM |

    Hi, Curtis--

    Exactly. There are going to be exceptions. However, I speak for the 80% or more people who do indeed have addictive and appetite-increasing relationships with wheat.

  • Shreela

    5/29/2011 6:08:03 AM |

    I wasn't able to fast when Dr. Davis started discussing it about 1-2 years ago. Most of my life, if I didn't "graze", I'd get hypoglycemic symptoms like my mother, and my paternal grandmother. My mother even got a note from my doctor that I had to have a sandwich before Jr high band practice, else I'd get headaches or light-headed - that's how long I've dealt with frequent hypoglycemia episodes.

    So I came up with my own personal mini-fast-challenge. I would only eat when an actual hypoglycemic symptom happened, ignoring the regular hunger pangs. Then when I ate, I avoided sugars, starch and wheat - I did have a bit of rice though. I'm guessing it was about 3-4 days before I could go 5-6 hours with no hypoglycemic symptoms, and about 10'ish days before I could go 12 waking hours with no calories (I draink tea with stevia).

    Looking back, both my parents' families ate lots of wheat: bread, biscuits, pasta, so that's probably what gave my paternal grandmother, mother, and then me our hypoglycemia. If I have a hypoglycemic symptom, I start my mini-fast-challenge again. I finally figured out my family's curse is wheat, so I avoid it except the occasional pasta dish.

  • Paul Lee

    5/30/2011 11:27:42 AM |

    I followed the "East Stop Eat" approach a while back, with good results. I agree with one poster that said best to skip the breakfast insulin surge. In fact I think the whole "three square meals" with grazing in between, needs to be challenged (perhaps one meal a day). My guess is that humans are designed to go days without food and have plenty of energy. Its an ability that needs to be regained. Also I gather fasting is good for HGH response, especially if combined with resistance training.

  • Matt Titus

    5/30/2011 4:34:48 PM |

    Dr. Davis, I have done intermittent fasting for a long long, I have lost count but I think that it has been 4 years. I do my version on a daily basis so it I am not as strict as someone who does this occasionally. Now that being said, my final meal of the day is the meal that I begin my fast so I keep it as nutritious and ketogenic as possible. So, I eat my final meal at around 7:00 P.M. I don't eat again until 3:00 P.M. the following day. Eating is such a treat and I eat very tasty low carb food when I break my fast. I will have my morning coffee with heavy whipping cream and MCT oil. Or I will have a glass of water with MCT oil. I take my vitamin D at this time of day because it wards off any allergy bugs lurking in the air. This summer I would like to lose 10 lbs so I will just kick up my fasting method in intensify my diet by keeping it balanced between protein and fats.

    I am not athletic in the least but I find that being active is not hindered during fasting. I strongly believe that we should not need to eat before exercise. Nor should we need to eat immediately after exercise.

  • Mary Titus

    5/30/2011 4:38:17 PM |

    Sorry, I just noticed that post came up under my husband's name. That post on fasting should come up under my name Mary...I am the one playing flute.

  • Mary Titus

    5/31/2011 4:27:54 AM |

    Yes, I do agree with you . I read about HGH becoming activated through a combination of fasting and resistance training.

  • bbtri

    6/6/2011 1:17:06 AM |

    18 hour fasts are easy, 24 hour fasts are hard, but once I break the 24 hour barrier, another 12-16 hours isn't bad.  My diet isn't wheat heavy, but I certainly don't avoid it.  What works for me is moderate physical activity, which gets me over the hump.  The hump may be the switchover from carb burning to fat burning, which moderate activity of a couple hours duration trains the body to do.

  • Whoosh

    6/9/2011 6:36:41 PM |

    I was quite sold on IF but keep finding conflicting findings, any comments on this ?

  • M R

    6/29/2011 9:22:19 PM |

    Dr. Davis,
    Please refer me to your source of  "wheat is destructive".  I have eaten Shredded Wheat breakfast cereal every day for 25 years.  It is the only breakfast cereal I am not allergic/sensitive to.  After eating it for breakfast, it fills me up and I do not eat again for 6 hours.  I understand about wheat products raising a person's glycemic index, but I have read that the fiber in Shredded Wheat takes so long to digest that it actually controls a person's blood sugar all day.
    I am a healthy, near ideal-weight 50 year-old female.  My experience finds this statement to be false: "wheat is a powerful appetite stimulant through its 2-hour cycle of exaggerated glycemia followed by a glucose low, along with its addictive exorphin effect".
    Thank you for your time.