Does Bone Broth Break a Fast?

This is a surprisingly common question.

To get it out of the way: Yes, it does. Bone broth contains calories, and true fasts do not allow calorie consumption. You eat calories, you break the fast.

However, most people aren’t fasting to be able to brag about eating no calories for X number of days. They fast for shorter (often intermittent) periods of time for specific health benefits. It’s entirely possible that bone broth “breaks a fast” but allows many of the benefits we associate with fasting to occur.

As is the problem with so many of these specific requests, there aren’t any studies addressing the specific question. The scientific community hasn’t caught up to the current trends sweeping the alternative health community. But we can isolate the most common benefits of fasting and see how bone broth—and the components therein—interact.

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Common Benefits of Fasting: Does Bone Broth Help or Hinder?


Fasting is a quick and easy (or simple) way to get into ketosis. You have little choice in the matter. Since you’re not eating anything, and your body requires energy, you break down body fat for energy. And because you’ve only got fat “coming in,” you’ll quickly start generating ketone bodies. If bone broth stops ketosis, it’s probably breaking the fast.

Bone broth doesn’t contain any digestible carbohydrates. Common additions like tomato paste and carrots might add a few tenths of a gram of carbohydrate to your cup of broth, but not enough to throw you out of ketosis.

Bone broth is quite high in protein, especially if you make it right or buy the right kind, but if it’s the only thing you’re consuming during your fast, the overall caloric load won’t be enough for the protein in broth to stop ketosis.

I can’t point to a paper. I know for a fact that I’ve consumed bone broth without affecting my ketones.

Fat Burning

Fat-burning is another important aspect of fasting. Since bone broth contains calories, you’ll probably burn slightly less fat drinking broth during a fast. But the calories come from protein, the macronutrient least associated with fat gain and most supportive of lean mass retention. And at any rate, your total calorie intake on a fasting+broth day will be under 100 calories—plenty low enough to promote fat loss.

Insulin Sensitivity

Over the long term, fasting is an effective way to improve insulin sensitivity and glucose tolerance. Most things that make you better at burning fat and expending, rather than storing, energy—like exercise, low-carb diets, weight loss in general—tend to improve insulin sensitivity over time. But the sometimes counterintuitive piece to all this is that in the short term, fasting can reduce insulin sensitivity. This is a physiological measure the body takes to preserve what little glucose remains for the brain. All the other tissues become insulin resistant so that the parts of the brain that can’t run on ketones and require glucose get enough of the latter to function.

There’s also the matter of sleep, fasting, and insulin sensitivity to consider. Some people report sleep disturbances during fasts, especially longer fasts. This is common. If the body perceives the fast as stressful, or if you aren’t quite adapted to burning fat, you may interpret the depleted liver glycogen as dangerous and be woken up to refuel in the middle of the night. Some people just have trouble sleeping on low-calorie intakes in general, and a fast is about as low as you can get. If that’s you, and your fasting is hurting your sleep, it’s most likely also impairing your insulin sensitivity because a bad night’s sleep is one of the most reliable ways to induce a state of insulin resistance. There’s some indication that total sleep deprivation creates transient type 2 diabetes.

That’s where bone broth comes in. A big mug of broth is one of my favorite ways to ensure a good night’s sleep. It’s a great source of glycine, an amino acid that has been shown in several studies to improve sleep quality and reduce the time it takes to fall asleep. It may “break” the fast by introducing calories, but a broken fast is preferable to bad sleep and the hit to insulin sensitivity that results from it.


Things fall apart. Cars, tools, buildings, toy trucks, civilizations. That’s entropy, which dictates that all things are constantly heading toward disorder. And people aren’t exempt. Our cells and tissues are subject to entropy, too, only we can resist it. One of the ways our bodies resist entropy is through a process of cellular pruning and cleanup called autophagy.  There’s always a bit of back and forth between autophagy and our cellular detritus, but it occurs most powerfully in periods of caloric restriction. Fasting enhances autophagy like nothing else because it’s a period of total caloric restriction.  If bone broth destroys autophagy, that’d be a big mark against drinking it during a fast.

Amino acids tend to be anti-autophagy signaling agents. When we eat protein, or even consume certain isolated amino acids, autophagy slows. Bone broth is pure protein. It’s almost nothing but amino acids. The key is: Which amino acids are in bone broth, and have they been shown to impede autophagy?

The primary amino acids that make up the gelatin in bone broth are alanine, glycine, proline, hydroxyproline, and glutamine.

Let’s say you’re drinking a mug of strong, really gelatinous bone broth with 15 grams of gelatin protein. How do those amino acids break down?

So it’s a mixed bag. The most prominent amino acid in bone broth—glycine—seems to allow autophagy, but the less proinent amino acids may not. It’s unclear just how much of each amino acid it takes to affect autophagy either way. The absolute amounts found in bone broth are low enough that I’m not too concerned.

What Else To Know…

Okay, so while bone broth technically “breaks” the fast, it may preserve some of the most important benefits. Is there anything else related to bone broth and fasting that deserve mention?

If you’re the type to train in a fasted state and eat right after, you might consider incorporating some bone broth right before the workout. Just like my pre-workout collagen smoothie does, bone broth (plus a little vitamin C to aid the effect) right before a workout improves the adaptations of our connective tissue to the training by increasing collagen deposition in the tendons, ligaments, and cartilage. You’ve already done most of the fast honestly. What’s shaving off a half hour of fasting time by drinking some broth or collagen, especially if you stand to improve your connective tissue in the process? Ask any older athlete and they’ll say they wish they could.

Some spices and herbs that are often added to bone broth can have effects similar to fasting. Take curcumin, found in turmeric. Research shows that it’s an independent activator of mTOR, which in turn can activate autophagy. Ginger and green tea (what, you haven’t tried steeping green tea in bone broth?) are other ones to try. Bone broth with turmeric, green tea, and ginger might actually combine to form a decent autophagy-preserving drink during a fast. Only one way to find out!

That’s about it for bone broth and fasting. If you have any further questions, don’t hesitate to ask down below.


Xu X, Wang X, Wu H, et al. Glycine Relieves Intestinal Injury by Maintaining mTOR Signaling and Suppressing AMPK, TLR4, and NOD Signaling in Weaned Piglets after Lipopolysaccharide Challenge. Int J Mol Sci. 2018;19(7)

De urbina JJO, San-miguel B, Vidal-casariego A, et al. Effects Of Oral Glutamine on Inflammatory and Autophagy Responses in Cancer Patients Treated With Abdominal Radiotherapy: A Pilot Randomized Trial. Int J Med Sci. 2017;14(11):1065-1071.

Shaw G, Lee-barthel A, Ross ML, Wang B, Baar K. Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr. 2017;105(1):136-143.

Zhao G, Han X, Zheng S, et al. Curcumin induces autophagy, inhibits proliferation and invasion by downregulating AKT/mTOR signaling pathway in human melanoma cells. Oncol Rep. 2016;35(2):1065-74.

Hung JY, Hsu YL, Li CT, et al. 6-Shogaol, an active constituent of dietary ginger, induces autophagy by inhibiting the AKT/mTOR pathway in human non-small cell lung cancer A549 cells. J Agric Food Chem. 2009;57(20):9809-16.

Zhou J, Farah BL, Sinha RA, et al. Epigallocatechin-3-gallate (EGCG), a green tea polyphenol, stimulates hepatic autophagy and lipid clearance. PLoS ONE. 2014;9(1):e87161.

TAGS:  Keto, prevention

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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30 thoughts on “Does Bone Broth Break a Fast?”

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  1. Hi Mark, I do the keto diet and fast 16 to 17 hrs. most days because I just feel the best when I fast. If I am really busy I can go days with nothing, but generally I take 1 TB. MCT oil in coffee about 14 hrs. in and it carries me to the end of the fast. There are days I also may do 1 cup bone broth added too. It never kicked me out of ketosis. When I think of my old eating habits this is like eating nothing! I love it! 🙂

  2. HI!
    Do you sell or could you recommend a bone broth to buy?
    I do not necessarily have time to make home made bone broth?
    Thank you!

    1. If you want to make home made and it’s mostly just a matter of time, an Instant Pot is a great help. You can make nice meat juice jelly out of a couple knuckle bones in just a couple hours.

      1. I find making bone broth is not that time consuming. I throw all the bones and vegetable trimmings in my slow cooker with water and let it go for 24 hours (Set it and forget it!)You could roast the bones ahead of time for a richer broth, but to save time it really isn’t necessary.

  3. I start the day with a mug of bone broth…either chicken or beef and I add turmeric powder, pepper, salt, sliced ginger and top it up with hot water. I have it after about 14 hours of fasting. I think the benefits out way anything else. I don’t like coffee so this is my start to the day. I keenly read the article as I’m such a broth fan.

    1. Catherine how much turmeric do you add to a mug of bone broth? ???? Thanks in advance ?

  4. In Sydney I love the brand Star Anise.
    On the Gold Coast I use Byron Bay which is not as good but I don’t make my own anymore.

  5. I was wondering how bone broth would do as part of a Fast Mimicking diet, using a 9% of calories from protein model.

  6. Thank you so much for this article!!! I have one day left of a four day fast and took bone broth on the first day. It really seems to help me through the fast. I simply forgot to take it the yesterday and today. I use an herbal tea at night to help me sleep through the night while fasting. I love the benefits of fasting. Thank you again!

  7. Funny you mentioned ginger and turmeric as I add both, along with a whole lemon and/or lime, to my list of ingredients when cooking my broth. Here’s another great tip: I juice turmeric root, ginger & lemon together in my Omega juicer and freeze in ice cube trays. I add a cube to curries and other dishes.

  8. Hi Mark,

    Great article, but a couple of amends are required with regards to mTOR. Firstly, you mention in the last paragraph that curcumin activates autophagy by activating mTOR. Reading the actual article abstract though, it states the opposite, ie the effect of curcumin “downregulating AKT/mTOR signaling pathway in human melanoma cells”.

    Secondly, and more widely, it is the activation of AMP-K that activates autophagy – which is in direct opposition to the mTOR ‘build and grow’/ anabolic pathway. Apart from exercise, nutrients that activate mTOR simultaneously down-regulate AMP-K, and by extension down-regulate autophagy. Hence the reason why taking significant levels of protein during a fast will up-regulate mTOR, down-regulate AMP-K, and by extension down-regulate autophagy. The study you mention on piglets states that glycine activates mTOR which in turn induces autophagy – but every study I have ever seen says that this cannot be the case, for the reasons given above. However, since glycine is not one of the anabolic branched chain or essential aminos, my assumption based on previous research studies would be that it actually DOWN-regulates mTOR, up-regulates AMP-K and thus activates autophagy via the established route of AMP-K up-regulation. Have you ever seen another study concluding that mTOR activation actually induces autophagy? I can’t help but think the piglet study is some kind of anomaly. I would love to hear your thoughts on this, as I believe that a good understanding of the mTOR/ AMP-K pathways are so crucial to maintaining good health.

    1. I think you may be on to something, mTOR run amuck can cause cancer cells to proliferate. We need mTOR for protein synthesis I believe, but as for most things in life there must be the correct balance, too little or two much of a critical chemical in our body (like T3 or T4) is problematic. The topic is way over my head, but I do eat a high protein diet with a lot of fat (and a ton of veggies and berries) and take curcumin and other supplements so hope I’m doing the right thing. 🙂

      1. Hi Healthy Hombre – yep I think you are definitely doing the right thing. Even Valter ‘low protein’ Longo agrees that having an acute boost in mTOR after a fast is extremely beneficial (he even implies it is MORE beneficial than the fast itself, stating that is where the good stuff actually happens). But we have to be clear that acutely up-regulating mTOR shifts you into the ‘build and re-grow’ phase. The cellular clean-up/ autophagy phase will be switched off at this point. So, like you I also tend to eat high protein: but in order to balance things out I IF most days for 16-18 hours, to allow AMP-K and the related autophagy space to kick in. Also, preliminary research from Sachin Panda’s lab indicates time-restricted feeding of protein increases the body’s sensitivity to dietary protein, ramping up protein synthesis when protein comes in after a fast. Interesting stuff!

  9. Hi Mark,
    I’ve been doing 18-20 hour water only fasts recently and feeling great. I tried to get to 24 hours and I became very light headed, weak and feeling lousy all over. I assumed it was my glucose being too low so I ate a handful of nuts and almost immediately felt better. Are some people unable to perform multi day fasts due to low blood glucose? Strangely though I’m not experiencing much weight loss, only a couple of pounds.

  10. “Bone broth with turmeric, green tea, and ginger might actually combine to form a decent autophagy-preserving drink during a fast. Only one way to find out!” You say this as if there is a way for us to try this and see. Since we cannot measure autophagy, this statement makes no sense.

  11. I’m reminded. I just felt like saying this eventually, about days when I consume green tea, cannabis, and fish: I am the alpha brain waves and the omega 3.
    I’ve thought of using teas in broths/soups/etc. before. I was thinking that if someone wants to eat rice, cooking it in chai tea would probably make it taste nice.

  12. I love the face of your yellow bone broth graphic. That’s exactly the look I got from my husband, when I said. drink this and only this till tomorrow noon, your guts need a rest.

  13. What about drinking a cup of black coffee with one tablespoon of coconut oil blended in? What affect does that have on fasting?

  14. Do probiotics or L glutamine throw you out of thefastinf state?


  15. Wow, so comprehensive and informative. Thank you for taking the time to write this.

  16. Is there a difference in chicken bone broth and beef bone broth. (chicken seems easier to get the ingredients for)

    Someone has said I need to boil the heck out of the bones til they all but disappear. I get a good gelatin for my several hours of cooking and the bones are soft. Do I need to go further?

  17. I’m confused… towards the end of the article, you talk about how curcumin is an “independent activator of mTOR, which in turn can activate autophagy.”
    But don’t we want to decrease mTOR in order to activate autophagy? My understanding is that when mTOR is increased, autophagy is decreased… or do I have that mixed up somehow?

  18. Great article that shockingly addressed ALL of my questions! I was surprised it had even been written lol.

    I have a few questions I would be eternally grateful if you happened to know the answers to:

    I’ve been drinking 5 calorie chicken bullion like 6 times a day – it’s <1 carb per serving and zero everything else except salt I believe. My question is if this will ruin my fast in regards to autophagy and insulin sensitivity? And if it will hinder them a bit is it just while it's being digested then my body resumes being a fat burning autophagy machine?

    PS: I'm on a 40 day fast – I have 2tbsp sugar free creamer with coffee a day, 6 bowls of this broth, and occasional diet sodas. I'm on day 9 so there's still time for me to stop if it will really hinder the benefits of doing full water

    Thanks in advance!

  19. Hi Mark I enjoyed the information I just read on bone broth and fasting. I’ve been doing intermittent fasting for 3 1/2 months without any thing except water during my fast. I wanted to ask you your opinion. Do you believe that if we fast, just say,18/6 That would be enough time for our body to go into autophagy? You know, I haven’t really changed my eating and I don’t calorie count and I really exercise except to do some walking and I feel like my body composition is changing up a little bit and that’s saying a lot because I’m 64 years old. So I just wanted to see what you thought about being able to change your body by doing the Intermittent Fasting Without lots of exercise or change in eating. Just to let you know, I Eat fairly clean. My main problem Area is that I love fruit And I ate way too much as far as the guidelines go.

  20. Appreciated this article! Just wanted to let you know- mTOR actually INHIBITS autophagy. So if glycine activates mTOR that means that that amino acid would actually decrease autophagy, not increase it.