Not So ... Fast ... (A Rant)

Hammers are great. Except for when you need a wrench.

Wrenches are great. Except for when you need a drill.

Drills are great. Except for when you need a crowbar.

Different job, different tool.

Different need, different tool.

With me so far?

With this in mind:

Fasting is great. Except when it’s not.

I think you’ll find I’m one of the more open-minded people in the low-carb/keto community. (I don’t know if this is good, bad, or meaningless. Maybe I should align myself with one camp and subscribe to that dogma and only that dogma. Then again, there’s enough of that out there already, right? And when Robb Wolf starts talking about eating lentils [as he did on this podcast], and Chris Kresser points out some of the potential dangers of going overboard with vitamin D supplementation, I guess I’m in good company if I’m able [and willing!] to see and respect the nuance some of this stuff requires.) I firmly believe in certain basic principles of nutrition that are forged in unalterable aspects of human physiology and biochemistry, but beyond that, if someone tells me they feel better eating a little bit of rice and potatoes now and then, and that they don’t feel so great loading up a cup of coffee with 4+ tablespoons of butter and coconut oil, who am I to insist they’re lying? Who am I to insist they force themselves to do something they insist makes them feel terrible? (Except bacon. If you’re not eating bacon, you are doing it wrong. [No, just kidding. Shout-out to anyone reading my blog who keeps kosher or observes the laws of halāl!])

So in my non-dogmatic perspective, what’s the deal with fasting?

Most of you are probably familiar with Dr. Jason Fung. Dr. Fung is one of my favorite people in the low carb health community. I love his salty language, razor-sharp wit, and pointed analogies. (I’ll link to some podcast interviews with him at the end of this post. As for the pointed analogies, listen for him talking about plane crashes and just needing “more lift and less gravity.” Classic!)

For those of you who live on Jupiter and have no idea who Dr. Fung is, he’s a nephrologist (kidney specialist) who regularly reverses obesity, type 2 diabetes, and kidney disease in his clinic. The humor, sarcasm, and snark in his blog posts puts mine to shame, and he manages to do so while being way more succinct than I am. (He should give lessons on how to do that...)

I respect Dr. Fung. I’m a huge fan. I loved his book and wrote a review of it here. In fact, we collaborated not long ago on a journal article that we’ll be submitting for peer review and publication. (Woohoo!) On his blog, in his YouTube videos, and in podcast interviews, he's written and talked about obesity, insulin resistance, hyperglycemia, and more. But what he is perhaps best known for is being a vocal proponent of fasting. Skipping a meal, skipping a whole day of meals, doing multi-day or even longer fasts: any and all permutations are okay, depending on what a patient’s goals are and what fits into their lifestyle. (He and Jimmy Moore are set to release a new book about fasting, and I can neither confirm nor deny that yours truly may have contributed some quotes…)

Dr. Fung has a multi-part blog series on the history and benefits of fasting as a religious, cultural, and health practice. He’s up to over 20 posts in the series, but he’s much more to the point than I am, and it’s well worth your time to read as your schedule permits. The first post is here, and each one ends (I think) with a link to the next one in the series. I am not at all doubting the success he’s had with patients. He is a doctor. I am not. As he says in interviews he’s done, when people ask him to address critics of his methods: he has supervised thousands of people through various permutations of fasting. People have generally only gotten better. Less medication. Lower insulin levels. Lower blood sugar. More energy. Greater fat loss. (And the critics? How many people have they supervised through fasting? How much proof do they have that fasting is dangerous? *Crickets.*)

Fasting has its place. I’m not going to write about the benefits of fasting. They are numerous, and if you want to know what they are, you can just check out the forthcoming book. And it should be obvious that, if I was quoted in a book about it, talking about it in a favorable way, then I do understand and respect these numerous benefits, and I think fasting can be incredibly therapeutic. (I talked about it in relation to neurological conditions toward the end of this podcast.) So I hope I’ve made it abundantly clear that I think Dr. Fung is awesome, and I think fasting can be awesome…

…when it’s applied intelligently and rationally, that is.

My fear is that many in the Paleo, low carb, and keto communities have sailed long past intelligence and rationality and have landed squarely in the twilight zone of insanity. Even worse, they are taking other people with them! People who should not fast!

Why do I care? Why does it affect me when someone who’s better off ingesting food on a regular basis chooses not to ingest food on a regular basis?

I care because I am the one who has to talk these people down from the proverbial ledge when they write to me complaining of fatigue, anxiety, loss of their menstrual cycle, or some other worrisome outcome.

I am concerned that the growing fascination (nay, obsession) with fasting is becoming a kind of orthorexia, wherein people become terrified of consuming food outside their self-prescribed window. Or consuming food before they were “supposed to.” People brag on social media about how long they’ve gone without food (and how much intense exercise they’ve done in that time). And even though no one comes right out and points a shaming finger at people who don’t fast, the result is that they still kind of make the rest of us feel like failures as human beings if we eat more than once every 24, 48, or 72 hours. Can we please stop this already?

Eating is a natural, biological imperative. We don’t have to do it multiple times a day, every day, but there’s not necessarily anything “wrong” with eating daily, either. At some point, we do need—and I mean need—to eat. That being said, many of us in the wealthy industrialized world probably do eat too much and too often. And I think Dr. Fung is doing people an important service by talking not just about what to eat, but when. It’s a big missing piece of the puzzle, particularly for people who struggle to lose body fat, or whose blood glucose and/or insulin isn’t coming down to healthier levels even on a “well-formulated” low carb diet. The conventional advice to “eat several small meals a day to keep your blood sugar up” has gotten us results about as nice as the ones that came from everybody basing their diets on starchy carbohydrates and using margarine instead of butter.

So yeah. Regardless of the type of diet those of us blessed with abundant food 24/7 follow—be it low fat, low carb, Paleo, keto, vegetarian—many of us probably do eat too often. We’re wired for feast and famine, not feast, feast, feast. We eat when we’re happy, sad, bored, excited, stressed out, lonely, watching television, celebrating, mourning, and just about anything and everything else. Because we are blessed with abundant food all year long, we now have to make a special effort to impose food scarcity upon ourselves for therapeutic purposes. I get it. I do.

Plenty of people fast, and plenty of people do great with it.

But let’s talk about who should not fast.

And I’m not talking about the obvious ones—the ones Dr. Fung, himself, is clear should not fast: pregnant women, breastfeeding women, children, and people with medical conditions or on certain medications for which fasting might be contraindicated.

I’m talking about healthy, young, active people who think they need to fast, but who actually seem to fare poorly in doing so. The people who seem to do poorly with fasting are not Dr. Fung’s typical patient base. Let’s remember, Dr. Fung is a nephrologist. Almost by definition, anyone who gets referred to him probably has some degree of kidney damage or dysfunction, and the vast majority of those with kidney damage or dysfunction not due to congenital problems or physical trauma most likely have insulin and blood glucose issues. For those of you who are fans of Dr. Bill Lagakos, I’ll emphasize his favorite phrase: context matters.

I have no doubt that Dr. Fung has had great success with his female patients. But what he doesn’t say—and I wish he would—is that the people he supervises on fasts are in his “Intensive Dietary Management” clinic specifically for diabetes, obesity, kidney disease, and the like. His patient population is NOT young, athletic, fit, healthy people who are already chronically undereating and not getting enough sleep, particularly when combined with intense workouts multiple times a week. This is a totally different ballgame! (Please take this with a grain of salt, because unlike Dr. Fung, I have not supervised thousands of people through fasts. But I do deal with the aftermath of what happens when people who should not fast can’t seem to shake the idea that they “should.”)

Based on what I see, hear, and read in the “Paleosphere,” the people who report the most trouble with fasting—the ones whose “adrenals crashed,” or whose “thyroid got killed”—are women. Usually younger women. Usually younger women who do a great deal of intense exercise. Usually younger women who do a great deal of intense exercise on insufficient calories (from whatever combination of macronutrients you like; doesn’t matter – the bottom line is, it’s just too damn little food). They also usually have full-time jobs and wake up at the crack of dawn to get in a spin class, boot camp, or CrossFit WOD, and sometimes do another one after work. These women are already in metabolic and hormonal danger. Add fasting to that mix and, yes, of course they don’t fare well. Why is this a surprise to anyone?!  (*Tap, tap.* Is this thing on?!)

(Case in point: Elle Russ, author of The Paleo Thyroid Solution. According to her profile as a “success story” on Mark’s Daily Apple: “I am 5’2”, I was 110–115 lbs, 16% to 17% body fat, and before hypothyroidism hit me, I exemplified the image of health and fitness. […] My doctor tested my thyroid incorrectly by only testing my TSH. He said the TSH was within range, I did not have a thyroid problem, and I just needed to exercise more and eat less, which I thought was impossible because I had been working out two hours a day and eating 1,200 calories or less…” To be clear, Elle wrote nothing about fasting. I am simply sharing her story as an example of who should not fast, but the kind of person I regularly hear from who is doing so. And I find it inexcusable that none of the doctors she ever saw for her thyroid suggested that she EAT MORE FOOD and EXERCISE A LITTLE LESS. [Also, perhaps 110 pounds and 16% body fat maybe did not “exemplify the image of health and fitness.” And please know I mean absolutely no disrespect toward Ms. Russ. As someone who has struggled with my own thyroid issues, I think her story is an important one, and I’m sure her book will be an incredibly valuable resource for other women, whose doctors are complete morons. I am simply speculating that her thyroid troubles might have—might have—been directly related to working out 2 hours a day on 1200 calories.])

So yes, fasting is great for women. Except for the women it’s not great for. I can almost guarantee you that none of the women claiming that fasting “wrecked their adrenals” or “trashed their thyroid” were 250 pounds, type 2 diabetic, and on five prescription medications. They were probably already following a low carb or Paleo diet, highly active, type-A personalities, severely under-fueling their activity, and already stressed to the max. These people are not suitable candidates for fasting.

So what’s up with men, then? Why do women seem to run into these issues far more often than men?

I do think there’s something to the argument that the female endocrine milieu is more “delicate” than that of males, but let’s get real: we delicate flowers can go without eating just fine. We’re not going to stop menstruating, or lose all our hair if we skip a couple meals now and then. The problems come when women combine meal skipping with unrelenting (and largely self-imposed) physiological stress, particularly if their normal, habitual food intake is already a long-term caloric deficit. It’s fasting on top of fasting and stress on top of stress. Robb Wolf and Chris Kresser often talk about the “allostatic load.” English translation: there’s only so much the body can take before (as Robb would say) the wheels come off the wagon.

The difference between the inappropriately fasting women and men of just about any stripe—stressed out, cool as a cucumber, lean, heavy, and anything in between—is that when men fast and do a hard workout, at some point, they will eat a huge meal. Maybe it will be immediately after the workout, or maybe they’ll wait 2, 4, 8, or 15 hours. But eventually, They. Will. Chow. Down. Not so with the women! They’ll fast and do a hard workout, and then “refuel” with three ounces of skinless chicken breast, a slice of avocado, and four cherry tomatoes. For all intents and purposes, they are already fasting. Compared to the demands they are placing on their bodies, they are already not eating anywhere near enough food. If we’re wired for feast and famine, then we’re wired for feast and famine, not famine and famine, or famine and eat a tiny bit of food, which, in the case of the women I’m talking about, are basically the same thing.

(To be clear, I do understand that, biochemically, eating a small amount of food is actually very different from full-on fasting. I’m just trying to make a point.) The larger point I’m trying to make here: if you’re gonna work hard, you gotta eat hard! This is the part most women are just not psychologically prepared to do. We have let magazines brainwash us into thinking that an effing ridiculous “deck of cards”-sized piece of virtually fat-free tilapia is enough to fuel a healthy adult human being. I can’t even… I seriously don’t even know what to say anymore. I get clients like this all the time. (And I will be writing quite the related rant about keto zealotry. Hang onto your hats for that one, folks.)

Okay, since I don’t know what to say anymore, even though there’s lots more I want to say, I’ll make this a two-parter. (Click here for part 2.)

In closing, I haven’t verified this with Dr. Fung, but I would venture to guess that he’s never had a 240-pound, type-2 diabetic female patient on six different medications claim that one of his recommended fasting regimens landed her in “adrenal fatigue” or induced hypothyroidism in her. Honestly, I kind of have to roll my eyes at the mere thought of that.

Like I said: fasting is great. Except when it’s not.

(Also: one more thing before I go: regarding the women who run into hormonal mayhem from fasting, I don't think it’s the fasting that’s the culprit. I think it’s the long-term caloric deficit combined with too-frequent intense exercise and unrelenting psychological stress. What the fasting does is exacerbate and bring to light problems that were already there. So it’s wrong of me to say that women who fit this description “shouldn’t fast.” What they more likely should avoid is exercising themselves stupid on 1200 calories a day and being insanely micronutrient depleted.)

P.S. If you would like to explore intermittent fasting, I highly recommend Dr. Ted Naiman’s guide, which you can find here. (Or the printable pdf version here. A great resource!)

And here are some good podcast interviews with Dr. Fung:

·        What Really Causes Obesity? (With Vinnie Tortorich, 3/4/2016)

·        Unlocking the Secrets of Weight Loss (With Vinnie Tortorich, 10/23/2015)

·        The Obesity Code (on the 2 Keto Dudes show)

And don’t forget one of my all-time favorites: The Two Big Lies of Type 2 Diabetes (Hint: It’s the Insulin, Stupid!)

Disclaimer: Amy Berger, MS, CNS, NTP, is not a physician and Tuit Nutrition, LLC, is not a medical practice. The information contained on this site is not intended to diagnose, treat, cure, or prevent any medical condition and is not to be used as a substitute for the care and guidance of a physician. Links in this post and all others may direct you to amazon.com, where I will receive a small amount of the purchase price of any items you buy through my affiliate links.