The Definitive Guide To What Breaks a Fast

One of the most common questions I get is “Does [x] break a fast?”

What they’re really inquiring about is: “Does this interfere with, negate, or nullify the benefits of fasting?”

These benefits include:

Ketosis: Fasting is the quickest way to get into ketosis, an metabolic state characterized by increasing fat burning, fat adaptation, and—in some people—improved cognitive function.

Fat Loss: When you’re fasting, you’re not eating, and not eating is the best way to force your body to burn the fat it already possesses. Fasting also means no additional calories are coming in, and many people find that fasting is a great way to control their calorie intake.

Autophagy: Autophagy, or “self-eating,” is the process by which our cells prune damaged components, maintain proper function, and keep aging at bay. Fasting triggers autophagy. Breaking the fast will stop autophagy.

Let’s go through the most popular queries one by one and figure out how each one affects an intermittent fast.

Common Drinks

Coffee

Depends on who you ask. Some say the fact that coffee triggers a metabolic response means it breaks the fast. I say that coffee increases fat mobilization and burning, independently triggers autophagy (something we’re looking for when we fast), and makes it easier to stave off hunger. For my full treatment, check out this post on coffee and fasting.

I’m going to say “no.”

Tea

Tea contains no calories, improves metabolic health, and can aid fat burning. All signs point to it being great during a fast. Of course, if you had a tablespoon of sugar and a half cup of milk, you’re breaking the fast. But tea itself is a great addition.

I’m going to say “no.”

Yerba Mate

Yerba mate is essentially non-caloric, like tea or black coffee. It also has beneficial effects on glucose tolerance, which is a big plus.

I’m going to say “no.”

Bone Broth

I covered this in full a few months ago. Go read that post. In short, a bit is probably okay. Just keep in mind that the more gelatinous your broth is, the more collagen protein it will contain and the greater its potential to inhibit autophagy. This isn’t established in humans yet (see the collagen section below), but it’s worth considering. A nice salty broth has gotten many a faster through a tough fast, especially if they’re still learning the ropes and need some electrolytes.

I’m going to say “technically yes” but “realistically no.”

Lemon Water

A tablespoon of fresh squeezed lemon juice has a couple calories and a decent amount of potassium. Combined with salt, lemon water is actually a nice way to hydrate during a fast without breaking it.

I’m going to say “no.”

Diet Soda

Diet soda may mess with your gut. It’s linked to weight issues, though not conclusively and certainly not in a causative manner; it’s just as likely that the relationship can be explained by overweight and unhealthy people using diet sodas in a bid to lose weight. I don’t like them myself, and I’ve witnessed people fail to ever kick the sweet tooth as long as they drank diet sodas. But many people find they do improve dietary adherence and do improve fasting tolerance. If that’s the case, they are very pro-fasting.

I’m going to say “no.”

Juice

A juice fast isn’t really a fast. You’re consuming fewer calories than you might eating normal food, but you’re still consuming a good number of calories—most of them carbohydrate, no less.

I’m going to say “yes” unless you’re specifically engaging in “juice fasting,” in which case it’s still not fasting despite what you call it.

Common Drink Additions/Condiments

Cream (Unsweetened)

Technically, as a source of calories, cream breaks a fast. But it doesn’t provoke an insulin response when consumed in isolation, it doesn’t impact ketosis, and many people find it makes sticking to the fast easier.

I’m going to say “technically yes, but realistically no—just keep it to a couple teaspoons or less.”

Almond Milk

It depends on the almond milk. A full cup of the standard sugar-free almond milk has just 36 calories, about a gram of carbs, 2 grams of fat, and a gram of protein. That’s almost nothing. You could probably get away with a quarter or third cup and have minimal impact on your fast, but why not just drink some water or coffee?

I’m going to say “technically yes,” but you can get away with a little bit.

Butter

Like cream, butter doesn’t provoke an insulin response in isolation. It’s more calorically dense than cream, though, so watch how much you eat.

I’m going to say “technically yes, but realistically no as long as you’re not using more than a teaspoon.”

MCT Oil/Coconut Oil

MCT oil is pure fat and thus calorically dense, but it has three benefits going for it. First, it doesn’t provoke an insulin response in isolation. Two, it increases energy expenditure. Three, it converts directly to ketones. People new to fasting can often speed up the fat adaptation process by incorporating a little MCT oil. Coconut oil is the main source of MCT oil, so it’ll have similar effects, though not as pronounced.

I’m going to say “technically yes, but realistically no—and it may even enhance your fasting experience when consumed in moderation.”

Cinnamon

I don’t advise eating cinnamon alone, dry, and isolated. It’s a terrible and potentially deadly idea. But in some coffee or tea during a fast? Sure. It can even improve insulin sensitivity.

I’m going to say “no.”

Salt

Salt does not break a fast. Actually, adding a pinch or two of salt to your water during a fast can increase your tolerance of the fasting process and improve hydration status.

I’m going to say “no.”

Non-caloric Sweeteners—First Natural, Then Artificial

Stevia

Stevia contains no calories and has no effect on insulin secretion (if anything, it increases insulin sensitivity). However, it’s often used to sweeten foods that do contain calories, so be mindful of how you’re using it.

I’m going to say “no.”

Monk Fruit

For a good overview of monk fruit, read this. Suffice it to say, monk fruit is similar to stevia in that it’s a non-caloric, naturally-occurring sweetener with unique health effects. It will not break your fast.

I’m going to say “no.”

Swerve

Swerve is a sweetener that blends erythritol (a sugar alcohol) and oligosaccharides (a prebiotic fiber that tastes kinda sweet) with natural flavors. Erythritol has no effect on insulin or blood glucose (you just pee it out mostly). I couldn’t find any studies on oligosaccharides during a fast, but as humans cannot by definition digest them, they shouldn’t affect the course of a fast.

I’m going to say “no.”

Xylitol

See the gum section above. Stick to reasonable amounts.

I’m going to say “no.”

Sucralose (a.k.a. Splenda)

Sucralose does not provoke an insulin response or increase blood glucose—great news for fasters who want to use it—but it does seem to impair whole body insulin sensitivity. That’s bad for everyone.

I’m going to say “no,” but there are other downsides.

Aspartame

Those same studies on monk fruit and stevia also tested aspartame, finding similar results. Aspartame does not provoke an insulin or glucose response. I’m no fan of the stuff, but I don’t see any evidence that it will break a fast.

I’m going to say “no.”

Supplementary Powders, Oils, Etc.

CBD Oil

Assuming you’re doing the kind of hemp oil that comes in droppers and not the kind that you pour from a culinary oil bottle, the caloric content can’t possibly impact your fast. There are no studies examining the metabolic effects of CBD in the fasted state, but I don’t see any reason why it would impact ketosis, autophagy, or fat-burning—and without psychoactive THC involved, you won’t be getting the munchies.

I’m going to say “no.”

Protein Powder

Protein powder provokes an insulin response, which opposes autophagy, which means you’re breaking your fast. Plus, protein powder contains calories.

I’m going to say “yes.”

Collagen

If you’re strict and technical, then yes, collagen breaks a fast. There’s evidence that glycine—the most prominent amino acid in collagen—can inhibit autophagy, but it was a convoluted animal study where inhibiting autophagy with large doses of glycine after brain injury actually improved outcomes. It probably doesn’t apply to someone adding a scoop of collagen to their coffee. Besides, even if it slightly reduces autophagy, a little collagen won’t negatively impact ketosis, fat-burning, or energy intake.

I’m going to say “technically yes,” but “realistically no.” Avoid if your main focus is autophagy, though.

Branch Chain Amino Acids (BCAAs)

BCAAs trigger an insulin response and thus stop autophagy and the fast. That said, many proponents of fasted training recommend using BCAAs before a workout to help preserve muscle and improve the post-workout anabolic response.

I’m going to say “yes.”

Apple Cider Vinegar

Apple cider vinegar is made by double fermenting the sugars present in apple juice. First, yeast convert the sugars to alcohol. Next, the alcohol converts to acetic acid. The result is a liquid that’s virtually calorie-free. Studies showing that consuming vinegar lowers the blood glucose response to a subsequent meal aren’t really relevant if you’re fasting, but they don’t hurt.

I’m going to say “no.”

Electrolyte Powder/Tabs

Electrolyte powders/tabs used to come festooned with sucrose, making them decidedly anti-fasting. These days, most of them are sweetened with stevia or some other natural non-caloric sweetener. Even the ones that have a little bit of sugar (1-2 g) are probably okay to consume without much negative effect. Best of all, electrolytes can really help you tolerate a fast.

I’m going to say “no.”

Breath-Freshening Items

Gum

If we’re talking sugar-rich gum, the answer is yes. Those definitely break a fast. If we’re talking xylitol gum, the answer is more mixed. In healthy individuals, 30 grams of pure xylitol triggers a small but significant rise in glucose and insulin. That might sound scary to a prospective IFer, but most people aren’t chewing gum made with 30 grams of xylitol. The average piece of xylitol gum barely weighs a gram.

I’m going to say “no,” unless you’re chewing gum made with real sugar or you’re throwing back 30 pieces of xylitol gum in a sitting.

Toothpaste

I always consume my toothpaste (around a tablespoon of the good stuff per brushing) and I’ve never had it knock me out of ketosis, autophagy, or in any way shape or form break my fast. I’m kidding. I don’t consume my toothpaste, but brushing your teeth doesn’t break a fast.

I’m going to say “no.” Don’t eat it though.

Mouthwash

Pretty much the same as toothpaste. Look for a brand that doesn’t contain sugar or one of the artificial sweeteners above that trips insulin. As the instructions (and common sense) suggest, don’t drink it.

That’s it, folks. If you have additional questions about what does or doesn’t break a fast, leave them down below. Thanks for reading, and I hope you found the post helpful. Forward it on if you did.

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References:

Hansson P, Holven KB, Øyri LKL, et al. Meals with Similar Fat Content from Different Dairy Products Induce Different Postprandial Triglyceride Responses in Healthy Adults: A Randomized Controlled Cross-Over Trial. J Nutr. 2019;149(3):422-431.

Anton SD, Martin CK, Han H, et al. Effects of stevia, aspartame, and sucrose on food intake, satiety, and postprandial glucose and insulin levels. Appetite. 2010;55(1):37-43.

Ili? V, Vukmirovi? S, Stilinovi? N, ?apo I, Arsenovi? M, Milijaševi? B. Insight into anti-diabetic effect of low dose of stevioside. Biomed Pharmacother. 2017;90:216-221.

Noda K, Nakayama K, Oku T. Serum glucose and insulin levels and erythritol balance after oral administration of erythritol in healthy subjects. Eur J Clin Nutr. 1994;48(4):286-92.

Müller-hess R, Geser CA, Bonjour JP, Jéquier E, Felber JP. Effects of oral xylitol administration on carbohydrate and lipid metabolism in normal subjects. Infusionsther Klin Ernahr. 1975;2(4):247-52.

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The Definitive Guide To Autophagy (and 7 Ways To Induce It)

Biological systems are self-maintaining. They have to be. We don’t have maintenance workers, mechanics, troubleshooters that can “take a look inside” and make sure everything’s running smoothly. Doctors perform a kind of biological maintenance, but even they are working blind from the outside.

No, for life to sustain itself, it has to perform automatic maintenance work on its cells, tissues, organs, and biological processes. One of the most important types of biological maintenance is a process called autophagy.

Autophagy: the word comes from the Greek for “self-eating,” and that’s a very accurate description: Autophagy is when a cell consumes the parts of itself that are damaged or malfunctioning. Lysosomes—members of the innate immune system that also degrade pathogens—degrade the damaged cellular material, making it available for energy and other metabolites.  It’s cellular pruning, and it’s an important part of staving off the worst parts of the aging process.

In study after study, we find that impairment to or reductions of normal levels of autophagy are linked to almost every age-related degenerative disease and malady you can imagine.

  • Cancer: Autophagy can inhibit the establishment of cancer by removing malfunctioning cellular material before it becomes problematic. Once cancer is established, however, autophagy can enhance tumor growth.
  • Diabetes: Impaired autophagy enables the progression from obesity to diabetes via pancreatic beta cell degradation and insulin resistance. Impaired autophagy also accompanies the serious complications related to diabetes, like kidney disease and heart failure.
  • Heart disease: Autophagy plays an important role in all aspects of heart health.
  • Osteoporosis: Both human and animal studies indicate that autophagy dysfunction precedes osteoporosis.
  • Alzheimer’s disease: Early stage Alzheimer’s disease is linked to deficits in autophagy.
  • Muscle loss: Autophagy preserves muscle tissue; loss of autophagy begins the process of age-related muscle atrophy.

Okay, so autophagy is rather important. It’s fundamental to health.

But how does autophagy happen?

The way it’s supposed to happen is this:

Humans traditionally and historically lived in a very different food environment. Traditionally and historically, humans were feasters and fasters. While I don’t think our paleolithic ancestors were miserable, wretched, perpetually starving creatures scuttling from one rare meal to the next—the fossil records show incredibly robust remains, with powerful bones and healthy teeth and little sign of nutritional deficits—they also couldn’t stroll down to the local Whole Foods for a cart full of ingredients. Going without food from time to time was a fundamental aspect of human ancestral life.

They worked for their food. I don’t mean “sat in a cubicle to get a paycheck to spend on groceries.” I mean they expended calories to obtain food. They hunted—and sometimes came back empty handed. They dug and climbed and rooted around and gathered. They walked, ran, stalked, jumped, lifted. Movement was a necessity.

In short, they experienced energy deficits on a regular basis. And energy deficits, particularly sustained energy deficits, are the primary triggers for autophagy. Without energy deficits, you remain in fed mode and never quite hit the fasted mode required for autophagy.

Now compare that ancestral food environment to the modern food environment:

Almost no one goes hungry. Food is cheap and plentiful, with the tastiest and most calorie-rich stuff tending to be the cheapest and most widely available.

Few people have to physically work for their food. We drive to the store and walk a couple hundred steps, hand over some money, and—BOOM—obtain thirty thousand calories, just like that. Or someone comes to our house and delivers the food directly.

We eat all the time. Unless you set out to do it, chances are you’ll be grazing, snacking, and nibbling throughout the day. We’re in a perpetually fed state.

The average person in a modern society eating a modern industrial diet rarely goes long enough without eating something to trigger autophagy. Nor are they expending enough energy to create an energy deficit from the other end—the output. It’s understandable. If our ancestors were thrust into our current situation, many would fall all over themselves to take advantage of the modern food environment. But that doesn’t make it desirable, or good for you. It just means that figuring out how to trigger autophagy becomes that much more vital for modern humans.

Here are 7 ways to induce autophagy with regular lifestyle choices.

1) Fast

There’s no better way to quickly and reliably induce a large energy deficit than not eating anything at all. There are no definitive studies identifying “optimal” fasting guidelines for autophagy in humans. Longer fasts probably allow deeper levels of autophagy, but shorter fasts are no slouch.

2) Get Keto-Adapted

When you’re keto- and fat-adapted, it takes you less time to hit serious autophagy upon commencing a fast. You’re already halfway there.

3) Train Regularly

With exercise-related autophagy, the biggest effects are seen with lifelong training, not acute. In mice, for example, the mice who are subjected to lifelong exercise see the most autophagy-related benefits. In people, those who have played soccer (football) for their entire lives have far more autophagy-related markers of gene activity than people of the same age who have not trained their whole lives.

4) Train Hard

In studies of acute exercise-induced autophagy, the intensity of the exercise is the biggest predictor of autophagy—even more than whether the athletes are in the fed or fasted state.

5) Drink Coffee

At least in mice, both caffeinated and decaffeinated coffee induce autophagy in the liver, muscle tissue, and heart. This effect persists even when the coffee is given alongside ad libitum food. These mice didn’t have to fast for the coffee to induce autophagy.

Certain nutrients can trigger autophagy, too….

6) Eat Turmeric

Curcumin, the primary phytonutrient in turmeric, is especially effective at inducing autophagy in the mitochondria (mitophagy).

7) Consume Extra Virgin Olive Oil

The anticancer potential of its main antioxidant, oleuropein, likely occurs via autophagy.

Disclaimer: The autophagy/nutrient literature is anything but definitive. Most studies take place in test tube settings, not living humans. Eating some turmeric probably won’t flip a switch and trigger autophagy right away, but it won’t hurt.

Autophagy is a long game.

This can’t be underscored enough: Autophagy is a lifelong pursuit attained by regular doses of exercise and not overeating every time you sit down to a meal. Staying so ketotic your pee tests look like a Prince album cover, doing epic 7-day fasts every month, fasting every other day, making sure you end every day with fully depleted liver glycogen—while these strategies might be “effective,” obsessing over their measures to hit some “optimal” level of constant autophagy isn’t the point and is likely to activate or trigger neurotic behavior.

Besides, we don’t know what “optimal autophagy” looks like. Autophagy isn’t easy to measure in live humans. You can’t order an “autophagy test” from your doc. We don’t even know if more autophagy is necessarily better. There’s the fact that unchecked autophagy can actually increase existing cancer in some cases. There’s the fact that too much autophagy in the wrong place might be bad. We just don’t know very much. Autophagy is important. It’s good to have some happening. That’s what we have to go on.

Putting These Tips Into Practice

Autophagy happens largely when you just live a healthy lifestyle. Get some exercise and daily activity. Go hard every now and then. Sleep deeply. Recover well. Don’t eat carbohydrates you don’t need and haven’t earned (and I don’t just mean “earned through glycogen depleting-exercise”). Reach ketosis sometimes. Don’t eat more food than you need. Drink coffee, even decaf.

All those caveats aside, I see the utility in doing a big “autophagy session” a few times a year. Here’s how mine looks:

  1. Do a big training session incorporating strength training and sprints. Lots of intense bursts. This will trigger autophagy.
  2. Fast for two or three days. This will push autophagy even further.
  3. Stay busy throughout the fast. Take as many walks as possible. This will really ramp up the fat burning and get you quickly into ketosis, another autophagy trigger.
  4. Drink coffee throughout the fast. Coffee is a nice boost to autophagy. Decaf is fine.

I know people are often skeptical of using “Grok logic,” but it’s likely that most human ancestors experienced similar “perfect storms” of deprivation-induced autophagy on occasion throughout the year. You track an animal for a couple days and come up short, or it takes that long to make the kill. You nibble on various stimulants plucked from the land along the way. You walk a ton and sprint some, then lift heavy. And finally, maybe, you get to eat.

If you find yourself aging well, you’re on the right track. If you’re not progressing from obesity to diabetes, you’re good to go. If you’re maintaining and even building your muscle despite qualifying for the blue plate special, you’ve probably dipping into the autophagy pathway. If you’re thinking clearly, I wouldn’t worry. Obviously, we can’t really see what’s happening on the inside. But if everything you can verify is going well, keep it up.

That’s it for today, folks. If you have any more questions about autophagy, leave them down below and I’ll try to get to all of them in future posts.

Thanks for reading!

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References:

Yang ZJ, Chee CE, Huang S, Sinicrope FA. The role of autophagy in cancer: therapeutic implications. Mol Cancer Ther. 2011;10(9):1533-41.

Barlow AD, Thomas DC. Autophagy in diabetes: ?-cell dysfunction, insulin resistance, and complications. DNA Cell Biol. 2015;34(4):252-60.

Sasaki Y, Ikeda Y, Iwabayashi M, Akasaki Y, Ohishi M. The Impact of Autophagy on Cardiovascular Senescence and Diseases. Int Heart J. 2017;58(5):666-673.

Florencio-silva R, Sasso GR, Simões MJ, et al. Osteoporosis and autophagy: What is the relationship?. Rev Assoc Med Bras (1992). 2017;63(2):173-179.

Li Q, Liu Y, Sun M. Autophagy and Alzheimer’s Disease. Cell Mol Neurobiol. 2017;37(3):377-388.

Jiao J, Demontis F. Skeletal muscle autophagy and its role in sarcopenia and organismal aging. Curr Opin Pharmacol. 2017;34:1-6.

Schwalm C, Jamart C, Benoit N, et al. Activation of autophagy in human skeletal muscle is dependent on exercise intensity and AMPK activation. FASEB J. 2015;29(8):3515-26.

De oliveira MR, Jardim FR, Setzer WN, Nabavi SM, Nabavi SF. Curcumin, mitochondrial biogenesis, and mitophagy: Exploring recent data and indicating future needs. Biotechnol Adv. 2016;34(5):813-826.

Przychodzen P, Wyszkowska R, Gorzynik-debicka M, Kostrzewa T, Kuban-jankowska A, Gorska-ponikowska M. Anticancer Potential of Oleuropein, the Polyphenol of Olive Oil, With 2-Methoxyestradiol, Separately or in Combination, in Human Osteosarcoma Cells. Anticancer Res. 2019;39(3):1243-1251.

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