Category Archives: Fasting - Page 2

Two Art de Vany-Related Ideas

I mentioned Art de Vany’s new book on Saturday; today I came across a few blog posts relating to some of his more important ideas and thought I’d talk about them.

The Economic Analysis of Diet

Today I recorded an interview with Jimmy Moore, which should appear on his “Livin’ La Vida Low-Carb Show” sometime early next year.

One of the things we talked about was our “economic” approach to nutrition and diet – how analyzing nutrients the way economists analyze factors of production helps sort out the confusing, seemingly contradictory results found in the scientific literature.

Since any factor calorie that is overly abundant will look like a “bad factor calorie” and any factor calorie that is too scarce will look like a “good factor calorie,” it’s easy to explain why the same nutrient can appear as “good” or “bad” in different studies.

Today, Mark Sisson features a passage from Art’s book. He says this:

At some point I realized that a human being is just another economic system. Indeed, your body contains an entire economy. There is the allocation of assets according to a hierarchy of needs. There are competing interests that sometimes struggle over resources and other times cooperate for the common good. There are surpluses. There are shortages. Like economies–like the movie industry–your body is a complex, decentralized system poised between chaos and order.

We tend to think of biologists as rigorous “hard” scientists and of economists as mushier “soft” scientists, but actually in analyzing complex cooperative networks economists are decades ahead of biologists.

The analysis in many biology papers, if translated into an economics paper with factors of production substituted for the dietary nutrients, would be recognized immediately by most economists as primitive and fallacious. Economists have developed many analytical ideas that diet researchers could usefully copy. It’s no surprise that Art and I both found our economics backgrounds helpful in sorting through the diet literature.

Intermittency in Diet

If there is a single idea that I associate with Art, it’s the desirability of intermittency and randomness to explore the extremes of the body’s metabolic networks.

Art touches upon this in the passage at Mark’s site:

According to chaos theory, certain systems that seem to be random in fact are not–it’s just difficult for us to perceive, at the outset, all the subtle factors that set the course and determine the outcome….

Another scientific concept, the power law, also comes up often in my discussions of health and fitness. It is based on the Pareto principle, named for Italian economist Vilfredo Pareto. In essence, it describes the relationship between how common a factor is and how much influence it exerts. It says that the most unusual events will have the greatest impact. Pareto’s study determined that 80 percent of privately held land in Italy was owned by 20 percent of the population.

Similar power laws exist all around us.

There is a power law of exercise, too: Your least frequent, most extreme exertions will have the greatest influence on your fitness. The peak moments of a workout count far more than the amount of time you spend working out…. When a work-out becomes an unvarying, monotonous routine, it loses its effectiveness.

Art’s ideas suggest that it might be beneficial to explore dietary extremes, for instance in calorie intake. Sometimes we should fast, forcing our body to economize on nutrients; sometimes we should feast, giving our body a surplus of nutrients that it has to dispose of.

In our book we discuss the benefits of intermittent fasting – it promotes autophagy, which extends lifespan and protects us against bacteria and viruses – but we don’t discuss whether feasting has any merits.

While there has been no real scientific study of feasting (except in the context of every-other-day implementations of intermittent fasting), feasting has been a hot topic in the Paleo blogosphere lately:

Coincidentally, Chris Masterjohn today offers us a review of Tim Ferriss’s new book, The 4-Hour Body.

For weight loss, Ferriss recommends intermittent fasting and feasting:

His fat-loss regimen sticks to a five-rule “Slow-Carb Diet” six days a week, but on the seventh day he resteth. This is the day for “reverse Lent,” otherwise known as bingeing on whatever the heck you want. In fact, Ferriss considers overfeeding one day a week to be a critical component of his fat loss regimen because of its effects on metabolism-boosting hormones.

In this respect he seems to have come to conclusions similar to those of Ori Hofmekler of Warrior Diet fame, who advocates fasting in the day and overfeeding in the night, and Matt Stone, whose High-Everything Diet uses overfeeding as its very lifeblood.

Stone recently told Jimmy Moore that one of the issues he’s still trying to tweak with his diet is to get rid of the initial gain in weight. Tim Ferriss may have solved that problem with his version of overfeeding, as folks on his diet usually gain weight on overfeeding day but nevertheless experience a net loss of several pounds per week from the very beginning.

So add Ferris to the group of self-experimenters who find benefits from occasional feasting.

Chris also discusses protein restriction:

Ferriss notes that periodic fasting from protein induces a process called autophagy, wherein the cell cleans out its mishandled, degraded, and aggregated proteins that otherwise accumulate. This is consistent with my experience. I had developed a problem with small wart-like risings on my hands and fingers at one point. Complete fasting for two weeks helped somewhat, but going vegan for two weeks made them completely disappear. The problem has never come back, despite my regular sumptuous feasting on animal foods of all kinds.

Perhaps protein cycling provides an answer to the question I had raised in The Curious Case of Campbell’s Rats. Namely, is there an intermediate intake of protein that maximally protects against cancer, toxicity, and fatty liver under all conditions? Perhaps the answer is not an intermediate intake of protein, but a periodic cycling of protein intake.

We note in our book (and this blog post) that protein restriction, even if calories are not restricted at all, promotes autophagy and therefore intracellular immunity and longevity. So we’re happy to endorse protein restriction.

But high intake of protein, especially of ketogenic branched-chain amino acids like leucine, does promote muscle synthesis. So what is a bodybuilder or athlete, who seeks the greatest possible muscle growth, to do?  Is there an inevitable conflict between athleticism and longevity?

It’s possible that protein cycling – say, a week of protein restriction followed by a week of high-protein intake – might help resolve the dilemma, providing 80% of the longevity and health benefits of protein restriction and 80% of the muscle synthesis benefits of high-protein diets.

If so, Art de Vany would not be surprised.

Neo-Agutak: “Eskimo Ice Cream”

UPDATE: Melissa has given this dish a great name: “Neo-Agutak,” after the Inuit dish Agutak or “Eskimo ice cream.”

Eating certain foods during a fast can increase its health benefits.

In the book we recommend coconut oil and fiber-rich calorie-poor plant foods. Our reasoning is:

  • Short-chain fats in coconut oil make the fast more ketogenic. Ketones have benefits for immunity, neuronal function, cancer suppression, and HDL production. They also reduce glucose requirements, making the fast less stressful.
  • Fiber in plants may be digested by gut bacteria to butyrate, a beneficial short-chain fat.
  • Anti-microbial plant compounds help fight gut pathogens and biofilms, shifting the balance of power in the gut toward commensal species.

Good food choices during a fast include green leafy vegetables, which are highly nutritious; traditional herbal spices, like oregano or turmeric, which have antimicrobial and anti-inflammatory activity; and berries, which are rich in antimicrobial compounds.

What I Ate During Today’s Fast

Baby spinach, cranberries, and coconut oil.

First, I put a layer of baby spinach in a bowl:

Next, I add cranberries and coconut oil:

Then, I heat them in the microwave for a few minutes. After the coconut oil has melted and the spinach shrunk, I add more spinach and cranberries. You can also add spices to taste. Then, another few minutes in the microwave so that most of the cranberries burst their skins, and let it cool. It will look like this:

This bowl has about 125 carb calories from a half-pound of cranberries, about 500 fat calories from coconut oil, and a host of gut-cleaning pathogen-disabling plant compounds. It tastes great (I think), and makes a passable Christmas decoration!

I started eating this about 1 pm. I had eaten 3/4 of it by 4 pm, when I added 3 egg yolks. It was finished by 6 pm. This was my only food before dinner.

Intermittent Fasting as a Therapy for Hypothyroidism

Reader Adam Kadela has begun intermittent fasting and wonders how it might affect his hypothyroidism:

I have a question pertaining to the section at the end of the book covering extended fasts. I regularly practice the 16-8 fast/feast protocol (breakfast at noon, last meal before eight), and plan to throw in a 36 hour fast once a month per your book. However, I am hypothyroid (hashimoto’s) and take synthetic T4 and T3 (unithroid and cytomel), so I’m wondering if an extended fast could affect my thyroid function negatively.

This is a great question. I think the daily 16-hour fast should be therapeutic for hypothyroidism, but I’m not sure about the 36-hour fast.

In today’s post I want to talk about why daily intermittent fasting may be therapeutic for Hashimoto’s, which is an autoimmune hypothyroidism.

Food Sets The Circadian Clock

The circadian clock is strongly influenced by diet: indeed, food intake dominates light in setting the circadian clock. If you regularly eat at night and fast during the day, the body will start treating night as day and day as night. [1]

(Alcohol consumption at night will also tend to reset the clock, which may explain why college students are often night owls!)

This suggests that controlling the timing of food consumption can help to maintain circadian rhythms.

The Circadian Clock and Hypothyroidism

The thyroid follows circadian rhythms. There is a circadian pattern to TSH levels:  high at night, low during the day.

The thyroid’s circadian pattern is diminished in autoimmune hypothyroidism. In a study of hypothyroid children, the night-time surge of TSH averaged 22%, compared to 124% in normal children. Only one of 13 hypothyroid children had a night-time TSH surge in the normal range. [2]

The study authors concluded:

We suggest that the nocturnal surge of TSH is important for maintenance of thyroid function and conclude that the nocturnal TSH surge is a much more sensitive test than the TSH response to TRH for the diagnosis of central hypothyroidism. [2]

Shift Work and Hypothyroidism

If circadian rhythms are important for thyroid function, we would expect shift workers to have high rates of hypothyroidism. Shift workers sleep during the day and eat at night, which disrupts circadian rhythms.

It turns out that shift work doubles the risk of autoimmune hypothyroidism:

Stress induces autoimmune disorders by affecting the immune response modulation. Recent studies have shown that shift work stress may enhance the onset of the autoimmune Graves hyperthyroidism. On the other hand, the possible association between occupational stress and autoimmune hypothyroidism has not yet been investigated…. Subclinical autoimmune hypothyroidism was diagnosed in 7.7 percent shift workers and in 3.8 percent day-time workers with a statistically significant difference: Odds Ratio (OR) 2.12, 95 percent Confidence Interval (CI) 1.05 to 4.29; p=0.03…. Our data show a significant association between shift work and autoimmune hypothyroidism. This finding may have implications in the health surveillance programs. [3]

Shift Work Affected Adam Too

In a follow up email, Adam told me that night shift work may have helped cause his hypothyroidism:

[T]he paper about thyroid and fasting … is particularly interesting to me due to my experience with night shift work for 10 months last year. My circadian rhythm was all out of whack due to experimenting with different sleep schedules and trying to workout around midnight before going into work at two a.m. I also played around with different diet strategies (grazing method w/ small meals, warrior diet, and ultimately settling on the 16-8, which is by far superior imo). My thyroid, along with other hormones, did not enjoy these trials.

Intermittent Fasting May Be Therapeutic

Since the circadian rhythm is affected by both food and light exposure, lifestyle practices can enhance natural circadian rhythms. These practices should optimize the circadian cycle:

  • Light entrainment:  Get daytime sun exposure, and sleep in a totally darkened room.
  • Daytime feeding: Eat during daylight hours, so that food rhythms and light rhythms are in synch.
  • Intermittent fasting: Concentrate food intake during an 8-hour window during daylight hours, preferably the afternoon. A 16-hour fast leading to lower blood sugar and insulin levels, and the more intense hormonal response to food that results from concentration of daily calories into a short 8-hour time window, will accentuate the diurnal rhythm.
  • Adequate carb intake:  Eat at least 400 “safe starch” carbohydrate calories daily during the afternoon feeding window. Relative to a very low-carb diet, this will increase daytime insulin release and, by increasing insulin sensitivity, may reduce fasting insulin levels. It will thus enhance diurnal insulin rhythm.

Adam tells me that intermittent fasting seems to be improving his hypothyroidism:

I think you’re correct in that I’ve experienced some curative effects. However, with the improved nutrient absorption and gut health from healthier eating and fasting, I think I fluctuate a lot b/w slightly hypo, normal, and hyper, since my medication is constant. I’m still in the process of finding a balance, but it’s a bigger improvement than my past state.


Many doctors mistakenly assume that little can be done to cure autoimmune disorders. In fact, however, autoimmune conditions commonly disappear once the chronic infections, food toxins, or poor health practices that cause them are eliminated.

Circadian rhythms have powerful influences on many biological processes, and disrupted circadian rhythms are a common feature of disease. Without clinical trials it’s impossible to be sure, but efforts to enhance circadian rhythms may be therapeutic for diseases such as hypothyroidism.

Intermittent fasting, daytime light exposure, excluding light from the bedroom, night fasting and daytime feeding are simple practices. But they may be underappreciated keys to good health.


[1] Fuller PM et al. Differential rescue of light- and food-entrainable circadian rhythms. Science. 2008 May 23;320(5879):1074-7.

[2] Rose SR et al. Hypothyroidism and deficiency of the nocturnal thyrotropin surge in children with hypothalamic-pituitary disorders. J Clin Endocrinol Metab. 1990 Jun;70(6):1750-5.

[3] Magrini A et al. Shift work and autoimmune thyroid disorders. Int J Immunopathol Pharmacol. 2006 Oct-Dec;19(4 Suppl):31-6.