This is a surprisingly
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
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
Common Benefits of Fasting: Does Bone Broth Help or Hinder? Ketosis
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 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.
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?
- 5 grams of glycine. In piglets, dietary glycine activates mTOR, the
pathway that triggers autophagy.
- 1.5 grams of alanine.
- 2.4 grams of proline.
- 2 grams of hydroxyproline.
- 1.75 grams of glutamine. 30 grams of
glutamine inhibits autophagy.
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
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.
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.