The Core Components of the 21-Day Bone Broth Diet
At its heart, the 21-day bone broth diet combines three core principles: a low-carb, whole-food diet, daily bone broth consumption, and intermittent fasting. This structure, popularized by naturopathic doctor Kellyann Petrucci, guides followers through a repeating weekly cycle for three consecutive weeks. The plan claims to leverage the nutrient-rich properties of bone broth while reducing overall calorie intake to promote weight loss and overall wellness.
The 5 Feasting Days
For five days of each week, the diet calls for following a clean, paleo-style eating plan. The focus is on nutrient-dense, unprocessed foods, with specific categories of food to be consumed and others to be strictly avoided.
Allowed Foods:
- Proteins: Grass-fed beef, pasture-raised poultry, eggs, and wild-caught fish are all encouraged.
- Vegetables: The plan emphasizes non-starchy vegetables such as leafy greens, broccoli, asparagus, and mushrooms.
- Healthy Fats: Healthy fat sources like avocados, nuts, olive oil, and seeds are included.
- Fruits: Limited amounts of low-sugar fruits, like berries, are permitted.
Foods to Avoid:
- Grains, including wheat, rice, and corn.
- Dairy products.
- Legumes.
- Added sugars and artificial sweeteners.
- Alcohol.
On these days, participants also consume 1 to 3 cups of bone broth as a snack, which helps to increase satiety between meals.
The 2 Mini-Fasting Days
Two non-consecutive days per week are designated as "mini-fast" days. During these days, solid food is largely eliminated. Instead, participants consume 3 to 6 cups of bone broth throughout the day, along with water and herbal tea. The protein and gelatin in the bone broth are intended to help manage hunger and provide some essential nutrients during this period of significant calorie restriction. Some variations allow for a small, approved snack on these fast days as well.
Potential Benefits and the Lack of Evidence
While specific studies on the 21-day bone broth diet are lacking, proponents point to potential benefits derived from its core components: intermittent fasting and clean eating.
- Weight Loss: The diet's calorie deficit, created by the fast days and restricted eating on other days, naturally leads to weight loss. The high protein and gelatin content of bone broth can also promote a feeling of fullness, which helps reduce overall calorie intake.
- Improved Gut Health: The collagen and gelatin in bone broth are believed to help strengthen the intestinal lining. Additionally, the elimination of common inflammatory foods like processed sugars and grains may reduce gut inflammation.
- Joint and Skin Health: The collagen found in bone broth is a key component of skin and connective tissues. Proponents claim that consuming it can improve skin elasticity and support joint health, though direct evidence for bone broth's effectiveness is limited.
Comparison Table: 21-Day Bone Broth Diet vs. Standard Reduced-Calorie Diet
| Feature | 21-Day Bone Broth Diet | Standard Reduced-Calorie Diet |
|---|---|---|
| Core Structure | 5 days of paleo eating, 2 days of modified fasting per week. | Consistent daily calorie deficit, no fasting required. |
| Food Restrictions | Highly restrictive: eliminates grains, dairy, legumes, sugar, alcohol. | Focuses on calorie control; generally allows for a wider variety of foods in moderation. |
| Weight Loss Mechanism | Calorie restriction, intermittent fasting, and increased protein intake from bone broth. | Consistent reduction of calorie intake below daily maintenance needs. |
| Sustainability | Short-term focus (21 days), with high risk of yo-yo dieting and rebound weight gain. | Promotes long-term, sustainable habits by focusing on moderation and overall balance. |
| Gut Health Approach | Relies heavily on bone broth and eliminating certain food groups. | Can incorporate a broader range of fiber-rich foods, proven beneficial for gut health. |
Risks and Considerations
The restrictive nature of the diet raises several health and sustainability concerns.
- Nutritional Deficiencies: Eliminating entire food groups like dairy and legumes can lead to insufficient intake of important nutrients, such as calcium, vitamin D, and fiber.
- Calorie Restriction: The fast days involve very low caloric intake (around 600 calories), which is well below the recommended daily allowance for most adults. This can lead to fatigue and other side effects.
- Yo-Yo Dieting Risk: The short, restrictive duration can make it difficult for participants to maintain results long-term. Deprivation often leads to overeating once the diet is complete, causing rebound weight gain.
- Lead Content Concerns: Some small studies have raised concerns about the potential for lead to leach from bones during the long simmering process, though other studies dispute this.
- Not for Everyone: Due to the fasting and low-carb approach, the diet is not suitable for pregnant or nursing individuals, those with a history of disordered eating, people with certain medical conditions, or high-intensity athletes.
The Verdict and Maintenance
The 21-day bone broth diet is an extreme, short-term plan that may yield rapid, but often temporary, weight loss due to calorie restriction. While bone broth offers some nutritional benefits, many of the diet's claims about skin tightening and extensive gut healing are anecdotal and not supported by rigorous scientific studies. For sustainable results, focusing on a balanced, whole-food diet and moderate exercise is a more reliable and less risky strategy. Those who complete the 21 days are advised to transition to an 80/20 maintenance plan, where they eat approved foods 80% of the time, with 20% flexibility. It is highly recommended to consult a healthcare professional or registered dietitian before starting this or any other restrictive diet.
Here is an external resource for more information: Dr. Kellyann's official website.
