# Bone Broth Fasting: Benefits, Rules & What to Expect
Bone broth fasting is a modified form of fasting where you replace solid food — for part or all of the day — with bone broth, while continuing to drink water. It gives your digestive system a rest, may support gut lining repair, and delivers protein and collagen without triggering a full insulin response. Most people find it far easier to sustain than a water-only fast.
This guide covers how bone broth fasting works, what the evidence says, how to choose the right format, and what to expect in your first few days.
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What Is a Bone Broth Fast?
A bone broth fast typically means consuming only bone broth (and water) for a set period — anywhere from 24 hours to 5 days. Some people do a "partial" bone broth fast, drinking broth in the morning and evening while eating one clean meal in between.
Unlike a water fast, bone broth provides:
- **Collagen and gelatin** — proteins that may support gut lining integrity
- **Glycine** — an amino acid associated with sleep quality and liver function
- **Electrolytes** (sodium, potassium, magnesium) — which help prevent the weakness many people feel when fasting
- **Glutamine** — an amino acid that may help maintain the gut mucosa during periods of caloric restriction
Because bone broth contains protein, it does technically break a strict fast (it will trigger some insulin response). However, the response is minimal compared to a full meal, which is why bone broth fasting is classified as a "modified" or "therapeutic" fast rather than a true water fast.
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Who Does Bone Broth Fasting?
Three main groups are drawn to bone broth fasting:
1. People doing intermittent fasting who want something more sustaining than water or black coffee during their fasting window — but don't want to break the fast with a full meal
2. People with digestive issues (IBS, leaky gut, bloating) who want to give their gut a rest while still getting nutrients
3. People doing a general reset after a period of heavy eating (post-holiday, post-illness) who want a structured, manageable approach
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The Potential Benefits of Bone Broth Fasting
Research on fasting in general is substantial. Bone broth specifically adds a few unique dimensions.
1. Gut Rest and Repair
When you remove solid food, your digestive system gets a break from the mechanical work of breaking down fibre, fats, and complex carbohydrates. This is associated with reduced bloating in most people.
The gelatin in bone broth may support the tight junctions in the gut lining — the gaps that, when compromised, are associated with "leaky gut." While human clinical trials are limited, glycine (abundant in bone broth) has shown promising effects on gut permeability in animal models.
2. Collagen Support Without Breaking the Fast Fully
A 250ml serving of grass-fed beef bone broth concentrate diluted with hot water delivers approximately 10–12g of collagen protein. This is well below the threshold that would significantly disrupt fasting ketosis in most people, while still providing the building blocks your body uses for skin, cartilage, and connective tissue repair.
3. Electrolyte Maintenance
One of the most common complaints during water fasting is weakness, headaches, and low energy — often caused by electrolyte depletion. Bone broth naturally contains sodium, potassium, and trace magnesium, which help maintain electrolyte balance throughout a fasting period.
4. Reduced Hunger and Cravings
Protein suppresses hunger hormones (particularly ghrelin). The small amount of protein in bone broth may make the fasting period more manageable compared to water alone — without the caloric load of a meal.
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How to Do a Bone Broth Fast
The Basic Protocol
24-Hour Fast:
- Morning: Start with water and black coffee or herbal tea
- Every 3–4 hours: Drink 200–300ml bone broth (prepared from concentrate or liquid)
- Evening: Finish with a final serving of broth
- Next morning: Break your fast with a light, easily digestible meal (eggs, steamed vegetables, lean protein)
3–5 Day Fast:
- Aim for 3–4 servings of bone broth per day (approximately 600–1,000ml total)
- Continue drinking water freely
- Take electrolytes if you feel faint or develop headaches
- Eat lightly when you break the fast — a sudden large meal can cause digestive distress after days of fasting
Choosing Your Bone Broth Format
Concentrate vs powder vs ready-to-drink:
| Format | Pros | Cons |
|---|---|---|
| Concentrate (gel) | Most collagen, no fillers, easy to portion | Needs diluting with hot water |
| Powder | Convenient, shelf-stable | Often contains maltodextrin/fillers; lower collagen content per gram |
| Ready-to-drink carton | Convenient | High water content, often low protein; expensive per serving |
For fasting, bone broth concentrate gives you the most protein and collagen per calorie — critical when you are limiting total intake. A 10ml portion of concentrate makes one serving and delivers more active collagen than most ready-to-drink cartons.
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What to Expect: A Day-by-Day Guide
Day 1
Most people feel fine on day 1. You may feel slightly hungry by the afternoon, particularly if you are used to grazing. The bone broth will take the edge off hunger without feeling like a full meal. Some people experience mild detox-style headaches if they normally consume a lot of caffeine or sugar — this is normal and usually passes.
Day 2–3 (if doing a multi-day fast)
This is typically the hardest stretch. Your body is shifting energy sources and hunger may spike. Stay consistent with broth timing — having a serving every 3–4 hours prevents the hunger from becoming overwhelming. Most people who successfully complete 3+ day fasts say day 2 is harder than day 3.
Breaking the Fast
This step matters. Do not break a multi-day fast with a large meal. Start with:
- Bone broth (a familiar, gentle first food)
- Soft-cooked eggs
- Steamed vegetables
- Plain yoghurt or kefir
Give your digestive system 24–48 hours to return to full meals.
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Who Should Avoid Bone Broth Fasting
Bone broth fasting is not appropriate for everyone. You should not attempt it without medical guidance if you:
- Are pregnant or breastfeeding
- Have a history of eating disorders
- Are on medication that requires food to be taken with doses
- Have diabetes or blood sugar management conditions
- Have kidney disease (bone broth is high in protein and certain minerals)
If you are unsure, speak with your GP or a registered dietitian before starting any fasting protocol.
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FAQ
Does bone broth break a fast?
Technically, yes — it contains protein which will trigger a small insulin response. However, the response is minimal compared to any meal, and many practitioners consider bone broth "fasting-compatible" in the context of therapeutic or modified fasting protocols. Whether it breaks a strict fast depends on your goal (ketosis, autophagy, weight management, gut rest).
How much bone broth should I drink when fasting?
Most protocols suggest 3–4 servings per day (600–1,000ml of prepared broth). This delivers sufficient protein to prevent muscle breakdown while keeping caloric intake very low.
Can I use bone broth powder instead of concentrate?
You can, but concentrate is preferable for fasting because it delivers more collagen per calorie and contains fewer additives. See our guide to bone broth concentrate vs powder for a full comparison.
Will bone broth fasting help me lose weight?
Bone broth fasting typically creates a significant caloric deficit, which may support weight loss in the short term. However, the more evidence-backed benefit is digestive rest and gut repair rather than sustained weight management. For lasting weight management, bone broth is best incorporated as part of a balanced diet — not relied upon as a long-term meal replacement.
Can I exercise while bone broth fasting?
Light exercise (walking, yoga, gentle stretching) is generally fine. High-intensity workouts during a multi-day fast are not recommended — your energy availability will be limited and your body is in a recovery mode.
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The Bottom Line
Bone broth fasting is a well-tolerated way to give your digestive system a rest while maintaining some protein intake and electrolyte balance. The collagen and gelatin in high-quality bone broth — particularly grass-fed, slow-cooked concentrate — make it a better companion to fasting than water alone, without the significant caloric load of a full meal.
If you want to try it, start with a 24-hour fast before committing to anything longer. Use a quality concentrate to get the most collagen per serving, and break your fast gently.
Explore our grass-fed beef bone broth — available in plain, turmeric, and garlic & herb flavours, with free UK delivery.
