There is increasing evidence from recent human and animal studies that intermittent fasting — refraining from food or caloric beverages for at least 12 hours a day, several days a week — reduces the risks of cardiovascular disease, dementia and cancer. Those benefits are well-documented in the hyperlinked articles, so I won’t repeat them here. Yet many nutritionists hold that skipping breakfast or other meals and snacks can lead to weight gain and metabolic imbalance. Several recent articles have suggested that IF and breakfast skipping is a particularly bad idea for women. Much to my chagrin, this view been even embraced recently by a number of ‘Paleo’ advocates whom I respect, such as Chris Kresser and Mark Sisson.
In this post I’d like to address three main objections that have been raised against skipping breakfast and other forms of intermittent fasting:
- It spurs hunger cravings, leading to compensatory overeating and obesity
- It causes cardiovascular disease and metabolic dysregulation of blood glucose and hormone levels
- It’s bad for women, leading to hormone imbalance, disrupted menstrual cycle, and heightened stress response
I believe these concerns with breakfast skipping are overblown, based on an incorrect interpretation of a few animal and human studies, and flawed personal implementation. To the contrary, adaptation to meal skipping can actually help boost stress tolerance and improve blood sugar control. If practiced correctly, intermittent fasting (IF) can actually be a powerful tool to overcome hypoglycemic symptoms, and regain control over a harried lifestyle. And it can be particularly useful for women who are struggling with cravings, weight management and stress management.
Opposition to intermittent fasting arises from both published research and anecdotal reports. I’d like to address both in this post. I’ll first point out some significant flaws in the interpretation of several recent studies purporting to show negative effects of reduced meal frequency on women and other groups. And I’ll end by pointing out how to avoid common mistakes made by many who try intermittent fasting find it to be unpleasant and unsustainable.
Approached correctly, IF can provide major health benefits for most us.
Hormesis is the ability of organisms to become stronger when exposed to low-dose stress. Is hormesis a basic principle of biology — or is it merely a strange but unimportant quirk of nature that only applies in exceptional circumstances?
Nassim Nicholas Taleb–the options trader turned philosopher–is intrigued by hormesis, and sees it as but one example of a much broader phenomenon: a fundamental principle he calls “antifragility”. The principle of antifragility applies not just to biology–but to sociology, economics, and perhaps even physics. Taleb has been developing this idea for a number of years. Antifragility made a subdued appearance in his 2007 blockbuster work, The Black Swan, a guide to dealing with unpredictable yet momentously consequential events in our increasingly volatile world. Taleb has now more fully developed the concept of antifragility in his most recent book, Antifragile: Things That Gain from Disorder.
The antifragile is the antithesis of the fragile. You might suppose that the opposite of “fragile” is something like “robust” — something that resists change. But Taleb points out that that would be the wrong answer. A fragile thing – a package of wine glasses, perhaps — is easily broken when subjected to a stressor, such as being dropped. Something robust is merely resistant to breakage. But an antifragile object actually benefits by being subjected to stress. Taleb conjures up an image of the fragile as an object we would ship in a box marked “Handle with Care”; by contrast, a box holding the antifragile would be labelled “Please Mishandle”
At first, this seems to be a tease. Are there really such antifragile things? Yes, indeed; the world is full of them, including you and me. And there are steps we can take to become ever more antifragile.
My recent post on Why I don’t take vitamin D supplements generated a lot of interest and a few misconceptions. In that article, I did not suggest any practical alternatives to taking high dose vitamin D supplements. Here I will suggest a way that may provide the benefits of vitamin D without popping any pills, spending all day in the sun, or ingesting copious amounts of fish.
Some readers got the idea that I believe vitamin D is not beneficial, and that I discount the evidence from studies that show the benefits. I want to dispel that notion. I do acknowledge the key role that vitamin D and the vitamin D receptor (VDR) play in bone mineralization and regulation of innate and adaptive immunity, and among other things. I further acknowledge that many (but certainly not all) studies support an association between higher vitamin D3 levels and reduced incidence of diseases such as cancer.
As I wrote:
Nobody doubts the important role of vitamin D in the body. But are higher levels of a hormone like vitamin D–whether or not provided as a supplement– always a good thing?
My doubts are focused on several points:
My article created a dilemma for several commenters. These people acknowledged the risks, but nevertheless cited benefits they personally experienced from supplementing with vitamin D–ranging from fewer colds and flu, to relief of autoimmune symptoms, and even lessening of depression.
For these people, a key question remains:
Is there a way to get the benefits of vitamin D supplementation, while avoiding the dependency and risks of taking vitamin D capsules daily for the rest of your life? While I don’t have a definitive proven answer to that question, recent research leads me to speculate here that there is a promising approach that is within everyone’s reach.
It lies within a powerful natural biological process called autophagy.
What a great conference! I had heard such high praise for the inaugural meeting of the Ancestral Health Symposium last August, but I was too late to register in 2011. This year I submitted an abstract that was accepted as a poster presentation. For those who missed it, I’ve attached a copy of my presentation below.
What an edifying and uplifting experience! We just wrapped up three days of excellent talks, panels, poster presentations and plenty of informal networking and socializing. This conference is really the hub of the Paleo movement. The emphasis was on the most recent developments in the scientific, cultural, political, and practical approaches to overcoming the contemporary health epidemics that derive from a mismatch between contemporary lifestyles and the biology of our evolutionary heritage. The talks and panels were diverse, covering nutrition, cholesterol, cancer, immune health, farming, exercise, and many other topics.
When does stress help you and when does it hurt you? There is no doubt that stresses of the wrong sort can lead to anxiety, emotional turmoil — and eventually depression and diseases like atherosclerosis and cancer. Yet a central theme of this blog is that certain stresses are “hormetic”: at the right dose and frequency, stress can actually make you stronger and more resilient. The many posts on this blog illustrate how stress can be channelled to build muscle, retrain appetite, improve eyesight, strengthen immunity, defeat allergies, and tame addictions and anger. Judicious exposure to stress can even promote joy and excellent health.
But one can come away from the study of hormesis with the misleading impression that it’s all about adjusting the level and timing of stressors to induce an appropriate adaptive or defensive response. In this article, I would like to focus on a frequently overlooked ingredient in hormesis: the role of intention, attitude and voluntary choice. If you omit this ingredient, you are leaving out an important element of the way that stress helps you become stronger.
Voluntary, deliberate exposure to stress can be particularly effective in providing psychological benefits, including overcoming anxieties, obsessions and phobias, and vanquishing appetite cravings, addictions. Beyond overcoming such self-defeating tendencies, deliberate exposure works to unleash confidence and generate a sense of joy and accomplishment.
How much weight lifting or other exercise is optimal for fitness? What is the right amount of carbohydrate restriction or fasting for sustained weight loss and health? What level of exposure to allergens will reduce allergies? How many hours of sun tanning is healthy? How frequently should plus lenses be worn to reduce myopia? Do I need to take cold showers every day to get their benefit? How much stress is enough — and how much is too much?
Many of the questions I get on this website and the forums are of this type. People understand the general concept of hormesis, namely that exposure to controlled amounts of stress can be beneficial, because it elicits beneficial adaptive responses in the organism. They understand that weight lifting builds muscles, and that intermittent fasting and calorie reduction can be healthful. But too much of any stressor — weight lifting, caloric restriction, sunlight, allergens — can have adverse consequences. With hormesis, it seems, the Goldilocks principle applies: to get a benefit, the level of stress must be “just right”. And because it’s so easy to veer into overload, many people seek to avoid even mild stress: Avoid allergens. Cover up with sunscreen. Eat frequent small meals. Don’t exert yourself. But if you choose this path, you forgo the possible hormetic benefits.
So how do you determine the optimum level and frequency of exposure to a stress? And how much rest or recovery between exposures is optimal? Read More
One of the primary topics covered on this blog is intermittent fasting (IF). Many approach IF as a diet or weight loss method. I know from research, personal experience and conversations with others that IF can indeed be an effective way to drop unwanted pounds. However, viewing IF as merely a new way to diet entirely misses what I believe is the most important reason to pursue it: the activation of hormetic processes that foster improved health, keep degenerative diseases at bay, and hold out the promise of a longer, more vibrant life. These benefits are a known consequence of calorie restriction, but intermittent fasting offers a more comfortable and versatile way to reap the benefits of calorie restriction without the sense of deprivation, the loss of lean body mass, and the metabolic risks that have been associated with simple calorie restriction.
It is because I’ve found intermittent fasting to be an attractive practice, both scientifically and personally, that I was so excited to be invited to give a lecture on IF at The 3rd Door, an innovative health and fitness studio, cafe and social center in downtown Palo Alto. The fitness director at The Third Door, Johnny Nguyen, is himself an advocate and practitoner of IF, which he blogs about with great flair and common sense at The Lean Saloon. The talk gave me an opportunity to reframe intermittent fasting in the terms of the philosophy of Hormetism, or applied hormesis that I write about on this blog. I believe that the framework of hormesis helps to make sense of why IF works, and why it is so much more than a diet.
What follows is a video of my talk on the benefits of intermittent fasting, presented on May 18, 2011 at The 3rd Door. I would like to thank Dianne Giancarlo and Johnny Nguyen for inviting me to speak, Vaciliki Papademetriou for technical assistance, Francesca Freedman for introducing me to The Third Door, Tom Merson for the still photos and Ken Becker for the masterful video production.
I’m writing this post the week before Thanksgiving, to give you something to think about as you are polishing off that last piece of pie….
One of the most common reactions I get to my advice to try intermittent fasting is: I could never do that!
Like the Jackson Browne song “Running on Empty,” the word “fasting” often conjures up dire images of starvation and energy deprivation. Many of you reading this post may have experienced strong hunger pangs, headaches, tiredness, sweating and even shaking or wooziness when going without eating for even part of a day, much less a whole day. So it is natural to extrapolate such experiences into the thought that going without food for a day, or even several hours, would invariably lead to uncomfortable or even dangerous hypoglycermic symptoms. That, together with the negative image of fasting as something unhealthy or associated with eating disorders, leaves most people pale at the thought of even attempting a short fast.
But I tell you, if you don’t try fasting you are missing out on an enjoyable, incredibly energizing experience that will put you in control of your eating and improve your health, your energy and your outlook. Many people, myself included, have learned to fast for up to a day or even longer, on a regular basis and without negative repurcussions. Done correctly, short-term fasting is not dangerous, it’s actually health-promoting and greatly helps to retrain your appetite. If you need to lose weight, the fast helps both in reducing basal insulin and retraining your appetite to be smaller. I’ve written about the benefits of intermittent fasting extensively on this site. Many of the Diet Links listed in the right-hand panel, such as fast-5 and Eat-Stop-Eat, amply document the safety and health benefits of fasting, dispelling the myths about “starvation mode”, slowing of metabolism, and loss of lean muscle mass. So I won’t reiterate here the voluminous evidence supporting the benefits of intermittent fasting. Our bodies are designed to last many days with out food, without great discomfort, and in fact it is beneficial to our health to forgo food periodically. But many of you are asking: Am I really up to this? How do I get started? Read More
Posted 23 May 2010 — by Todd
One of the first scientifically rigorous demonstrations of the benefits of hormesis was a 1934 study of calorie restriction (often abbreviated “CR”) in laboratory rats, conducted by Mary Crowell and Clive McCay at Cornell. They found that reducing the calories of rats by 30-50%, supplemented with adequate micro-nutrients, could almost double their lifespans. Later studies found continued lifetime extension with calorie restriction up to 65%. In addition, the rats remained energetic and youthful in appearance, with greatly reduced incidence, and delayed onset, of age-related diseases. This same phenomenon has been observed in a variety of other animals.
Studies on calorie restriction in primates or humans are as yet inconclusive. Controlled primate studies only started in the late 1980s and have yet to be completed, although the preliminary indications are very promising. And in humans it is more difficult to conduct controlled studies for both ethical and compliance reasons. An additional factor to consider is that animals raised post-weaning on calorie restricted diets typically have much smaller adult body sizes that animals not restricted in their eating. Because of the social and physical implications of this consequence, advocates of calorie restricted diets for humans advise that they be started only upon reaching adulthood.
Whether or not a restricted calorie diet extends the human lifespan, the evidence is becoming overwhelming that a nutritionally complete diet with reduced calories has the potential to greatly improve our health, particularly as we age. But is it practical and possible for humans to happily adhere to such a diet?