Bone broth on keto and while fasting.

Will bone broth break my fast?

Not in any way that undoes what you are fasting for. A 240ml cup of our broth is 31 to 50 kcal depending on the blend, with 0.8 to 1.3g of carbohydrate and 5.9 to 11g of protein. That is a rounding error against a day's intake, and it barely moves blood sugar or insulin.

Intermittent fasting works by keeping the eating window narrow and insulin low. A cup of savoury broth does neither harm — no sugar spike, no rebound hunger, nothing to knock you out of a fat-burning state.

The one exception is a strict water-only fast: a research autophagy protocol, or the hours before a blood test or procedure. Then it is water only, and your clinician's instructions win.

Where broth genuinely helps during a fast

• Electrolytes. Most fasting headaches and lightheadedness are sodium and fluid, not hunger.
• Warmth. A hot savoury cup blunts appetite far better than cold water.
• Structure. It gives the long hours a marker, which is often what makes a longer fast survivable.
• A clean edge to the window. Breaking a fast on broth before a full meal is gentler on the stomach than breaking it on a heavy plate.

Bone broth on keto

Macro-wise it is one of the easiest things on a ketogenic diet. Our broths run at 0.8 to 1.3g carbohydrate per 240ml, around 0.4 to 1g fat, and 5.9 to 11g protein. Nothing there disturbs ketosis at normal intake.

The bigger benefit is in the first two or three weeks. As glycogen falls, the body sheds water and with it sodium, potassium and magnesium — the fatigue, headache and cramp cluster people call keto flu. A cup of broth once or twice a day is the simplest way to put some of that back, without a powdered electrolyte drink.

It is also a good base for keto cooking: braise greens in it, make a fat-added soup, or use it in place of water when cooking cauliflower rice.

A simple daily pattern

• 16:8 eating window: one cup around hour 14, when hunger usually peaks.
• 24-hour fast: two cups spread across the day.
• Keto, first fortnight: a cup morning and late afternoon.
• Keto, settled: one cup daily as a protein top-up, or as a cooking base.
• Breaking any fast: broth first, then a full meal 20 to 30 minutes later.

What to look for

Read the label. Many so-called broths are stocks with added sugars, maltodextrin or yeast extract — small amounts of carbohydrate that matter when you are counting them. Look for a 36 hour simmer, a short ingredient list, stated protein per serving, and a broth that gels when chilled.

Common questions

Does bone broth break a fast?

Not for intermittent fasting. At 31 to 50 kcal per 240ml with almost no carbohydrate, it keeps insulin and blood sugar essentially flat, so it doesn't undo what a fasting window is doing. Only a strict water-only fast, or medical fasting instructions, rule it out.

How many carbs are in bone broth?

Our broths contain 0.8 to 1.3g of carbohydrate per 240ml serving depending on the blend, which fits comfortably within ketogenic macros.

How much protein is in a cup of Matsu broth?

5.9g of protein per 240ml in the beef and chicken blends, and 11g in the unsalted Pure Chicken broth.

Does bone broth help with keto flu?

It supplies sodium and trace minerals lost as the body sheds water in the first weeks of a ketogenic diet, which is the usual cause of keto-flu symptoms. A cup once or twice a day is the simplest approach.

What is the best time to drink broth in a fasting window?

At the point where hunger peaks — usually 12 to 15 hours in — and again as the first thing you take when you open your eating window.