The 21-day bone broth diet was first popularized by Dr. Kellyann Petrucci, who wrote the book Dr. Kellyann’s Bone Broth Diet.

Since then, many other practitioners of the low-carb, paleo, and intermittent fasting mindsets have used or adapted the concept

One cup of bone broth contains: – 42 calories – 0.6 grams of fat – 0.4 grams of carbohydrates – 8.8 grams of protein – 17% daily value of vitamin B3 – 12% daily value of vitamin B6

– 12% daily value of selenium – 9% daily value of vitamin B12 – 8% daily value of potassium – 7% daily value of vitamin A – 7% daily value of phosphorous – 5% daily value of choline

Dr. Kellann's regimen doesn't involve drinking bone broth for 21 days. On six of the 21 days, you drink just bone broth while following a rigorous paleo diet.

Bone broth isn't stock. It comes from ancestral food habits that included bones. Animal bones were boiled for 24 hours to extract nutrients.

Collagen is vital for skin, tendons, and joints. Bone broth includes collagen that can support the body's own collagen storage, relieving arthritis and other inflammatory joint diseases.

A bone broth diet is a modified fasting plan, incorporating principles of intermittent fasting. When most people think of fasting, they think of not eating anything at all.