Bone Broth and Fasting: Will It Break Your Fast?
Your fast, your answer
What kind of fast are you doing?
Keep your 16 fasting hours clean: water, black coffee, plain tea. A cup of broth runs 30 to 50 calories and 5 to 10g of protein1, which fails every strict definition of a fast (the accepted rulebook: over about 10 calories breaks it). But here's the part most pages skip: the best place for broth in a 16:8 routine is the moment your window opens. Your gut has been empty for 16 hours, and warm liquid protein is the gentlest first thing you can give it. The rule: nothing during the 16, broth first at the open.
This is where broth earned its reputation. Long-fasters openly call broth-assisted fasting "dirty fasting" and use it deliberately: one warm cup at the hard point (many say the wall hits around hour 36) can be the difference between finishing and quitting. What you're really getting is sodium, potassium and magnesium, the minerals behind the classic fasting headache, plus something warm to hold. Yes, it technically ends the "pure" fast. The long-fast community accepts that trade with open eyes. The rules, from people who do this: one cup, not two. Two a day on a 72-hour fast is widely considered too much. Save it for when you genuinely need it.
If your reason for fasting is autophagy, the cellular cleanup process fasters chase, broth is off the menu, and we won't pretend otherwise. Its protein (even 5g) triggers an insulin and mTOR response, and mTOR is the switch that pauses autophagy. This camp fasts "clean": water, black coffee, plain tea, nothing else. Broth's place in an autophagy protocol is at the end, as your first gentle step back to food. The rule: during, no. To finish, yes.
Keto note: easier answer. Plain broth carries little to no carbs, so it won't kick you out of ketosis, even when it breaks a "clean" fast.
Still gritting through the last few hours of your window? Water, black coffee and plain tea are your friends right now. A proper serve of bone broth protein isn't for mid-fast sipping, it's your reward the moment your window opens.
The bit nobody explains
What actually happens when you break a fast
By the end of a fast your body is in a different state, which is why what you break it with matters more than usual.
Your gut has been resting
Digestion winds right down during a fast. Heavy or greasy food lands hard on a system that's been idle for hours.
Blood sugar is primed to spike
After hours without food you're more insulin-sensitive, so a sugary "reward" hits faster and crashes harder.
Minerals are running low
Sodium and potassium dip while fasting. That's the headache-and-slump feeling near the end.
So the ideal fast-breaker is gentle, liquid, rich in protein and minerals, and easy on blood sugar. Bone broth ticks every box… almost.
The catch
A cup of broth is
mostly water
Every camp above ends at the same place: broth is the gentle way back in. Now look at the numbers you've just seen. A cup of broth carries 5 to 10 grams of protein1. As a first step, lovely. As rebuilding material after your body has been running on reserves, thin. One 2019 analysis found many broths' amino acid levels too low to deliver what's claimed of them2.
So how do you keep broth's gentleness, and get a real serve of protein at the same time?
This is where bone broth protein comes in
The same broth, with the water taken out
Bone broth protein is exactly what it sounds like: real bone broth, concentrated into a powder. hewn makes ours the slow way.
Grass fed bones
Beef bones from New Zealand farmers, 100% grass fed and finished.
Simmered for hours
Slow-cooked with vegetables and spices until the collagen and protein are drawn from the bones.
The water removed
What's left is broth in its most concentrated form: 15.3g of protein and 12g of collagen per serve, instead of 3g in a watery cup.
Flavoured with real food
Real cacao or real vanilla bean. No synthetic flavours, no artificial sweeteners.
Here's the honest part, and it lands better than it sounds: you were never really after a zero-calorie sip. You were after something worth breaking your fast for, instead of undoing your effort with a heavy meal. That's exactly what a real serve of bone broth protein is.
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Break your next fast with real protein
15.3g protein, 12g collagen, real cacao or vanilla. Your reward the moment your window opens.
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Fasting questions, answered straight
What people ask us
Does bone broth kick you out of ketosis?
No. At roughly 2g of carbs a serve, bone broth is keto-friendly, whether it's a thin cup or a concentrated serve.
How much bone broth can I have without breaking my fast?
Strictly, anything over about 10 calories breaks a fast, and a cup of broth is 30 to 50 calories. On long fasts, the working rule from experienced fasters is one cup at the hard point, not two. A full serve of bone broth protein (88 calories, 15.3g protein) is a fast-breaker, so save it for ending your window.
Is bone broth protein powder the same as liquid broth for fasting?
No, and that's the point. A thin cup is the sip-through tool some fasters allow themselves. A serve of bone broth protein is concentrated food: it breaks any fast, which is exactly why it belongs at the end of one, not during it.
Does it break autophagy?
Yes. Protein triggers the mTOR response that pauses autophagy, so keep a strict autophagy fast to water, black coffee and plain tea, and use bone broth to end it well.
When should I drink it?
At the end of your fast, as your first nourishment. Blended into a smoothie or stirred warm, one scoop, sipped slowly.
What about longer fasts, like 24 to 72 hours?
Most long-fasters who use broth sip one thin cup at the hard point, mainly for the sodium, potassium and magnesium. Then the longer the fast, the gentler the refeed should be: a liquid, protein-rich first serve instead of a heavy meal is exactly the job bone broth protein does well.
Which flavour is best for breaking a fast?
Both work beautifully. Velvet Cacao is the crowd favourite warm; Creamy Vanilla shines in smoothies.
Sources
- Shaw MH, Flynn NE (2019). Amino acid and macronutrient content of bone broth. Journal of Undergraduate Chemistry Research.
- Alcock RD, Shaw GC, Burke LM (2019). Bone broth unlikely to provide reliable concentrations of collagen precursors compared with supplemental sources of collagen. International Journal of Sport Nutrition and Exercise Metabolism.
- Lowe DA, et al. (2020). Effects of time-restricted eating on weight loss and other metabolic parameters. JAMA Internal Medicine.
- Morell P, Fiszman S (2017). The role of protein in satiation and satiety. Food Hydrocolloids.
Fasting practices described on this page reflect common conventions in fasting communities, not health advice. Speak with your healthcare professional before starting any fasting protocol.
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Break a few fasts with it. If you don't feel the difference, we'll refund you. Simple.
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