What is the 21 day soup diet?

October 16, 2025 •

3 min read

According to several observational studies, individuals who regularly consume soup tend to have a lower body mass index (BMI), which aligns with the premise of a 21 day soup diet. This article breaks down the mechanics, claims, and potential downsides of this popular short-term weight loss plan.

Quick Summary

A popular fad diet promising rapid weight loss, the 21 day soup diet involves consuming primarily low-calorie, vegetable-based soups, often with other food restrictions. Health experts caution against its restrictive nature, potential nutrient deficiencies, and unsustainability for long-term weight management. It is designed for short-term use and requires careful consideration of health risks.

Key Points

Restrictive Nature: The 21 day soup diet is a short-term, low-calorie plan that significantly restricts food intake, focusing primarily on vegetable or bone broth-based soups.
Potential Risks: Due to its restrictive nature, the diet poses significant risks, including nutrient deficiencies, muscle loss from low protein intake, and metabolic slowdown.
Unsustainable Results: Rapid weight loss on the diet is often from water loss, with weight typically regained once normal eating patterns resume, creating a 'yo-yo dieting' effect.
Expert Caution: Health professionals advise against this and other fad diets, recommending balanced, sustainable eating patterns for long-term health and weight management.
Healthy Alternatives: Incorporating nutrient-dense, low-calorie soups into a balanced diet is a safer, more effective strategy for sustainable weight loss.
Medical Consultation: Individuals considering this diet should consult a healthcare provider or registered dietitian to ensure it is appropriate for their specific health needs.

Understanding the 21 Day Soup Diet

The 21 day soup diet is a short-term, low-calorie eating plan centered on consuming vegetable-based, and sometimes broth-based, soups. It is a variant of several fad soup diets, which often promise significant and rapid weight loss over a defined period. The diet is highly restrictive, limiting intake of whole food groups like grains and some proteins to create a large calorie deficit. Health professionals do not recommend these extreme plans for long-term health due to nutritional imbalances.

A popular version is the 21-day bone broth diet, which combines a low-carb, Paleo-style diet for five days a week with two days of 'mini-fasting' on bone broth. Other restrictive soup diets, like the 7-day cabbage soup diet, follow similar principles of severe calorie and food group restriction.

Potential Benefits and Promised Results

Proponents often highlight rapid weight loss as a key benefit, attributing it to the significant calorie reduction and the satiating effect of high-water, high-fiber soups. Other claims include increased vegetable intake, simple meal preparation, and improved digestion due to higher fiber content.

Significant Risks and Drawbacks

Experts criticize extended soup diets for various health risks. These include potential nutritional deficiencies from eliminating food groups, muscle loss due to low protein intake, and a slowed metabolism from severe calorie restriction. Weight loss is often water weight and is quickly regained, leading to an unsustainable 'yo-yo dieting' cycle. The diet's monotonous nature and low energy intake can also cause fatigue and make it hard to stick to.

Comparison: Soup Diet vs. Balanced Weight Loss Plan


Feature	21 Day Soup Diet	Balanced Weight Loss Plan
Sustainability	Not sustainable. Designed for short-term, rapid weight loss.	Highly sustainable long-term. Focuses on lasting lifestyle changes.
Nutrient Intake	Limited and potentially deficient in essential nutrients like healthy fats, complex carbs, and protein.	Includes all major food groups for a comprehensive nutrient profile.
Weight Loss Type	Primarily water weight, often regained quickly.	Gradual, consistent fat loss, maintained through sustainable habits.
Metabolic Impact	Can cause metabolic slowdown due to severe calorie restriction.	Supports a healthy metabolism through moderate calorie control and consistent eating.
Flexibility	Highly restrictive, with specific and limited food options.	Flexible, allowing for a wide variety of foods and mindful eating.
Health Impact	Potential for nutrient deficiencies, fatigue, and muscle loss.	Promotes overall health, including better energy levels, digestion, and long-term well-being.

Sample 21-Day Soup Diet Meal Plan (Based on Principles)

For those considering a 21-day soup diet, here is a representative example illustrating its restrictive nature, based on a popular bone broth diet variant. This sample plan avoids grains, legumes, dairy, and added sugars:

Days 1-5 (Paleo-Style Eating):

Breakfast: Eggs with spinach.
Lunch: Chicken and vegetable stir-fry.
Dinner: Lean beef with steamed broccoli.
Snacks: Bone broth.

Days 6-7 (Bone Broth Fasting):

All Meals: Bone broth, water, and herbal tea.

This cycle is repeated over three weeks. This is very hard to sustain and nutritionally incomplete. A healthier approach is integrating nutritious soups into a balanced plan.

Healthy Soup Alternatives for Sustainable Weight Loss

Incorporating nutrient-dense soups into a balanced diet is a safer and more effective long-term strategy. Examples include:

Hearty Vegetable Barley Soup: Provides fiber from vegetables and whole-grain barley.
Lentil Soup: A protein and fiber-rich option.
Minestrone Soup: Contains a variety of vegetables, beans, and pasta.
Chicken and Vegetable Soup: Offers lean protein and vitamins.

Conclusion: A Quick Fix with Hidden Costs

The 21 day soup diet is a quick but unsustainable weight loss method. Initial weight loss is often water loss and quickly regained. Its restrictive nature carries risks like nutrient deficiencies and metabolic issues. For lasting health, integrate nutrient-rich soups into a balanced diet instead of relying on a drastic cleanse. Consult a healthcare professional before starting any restrictive diet. Research suggests pre-meal soup can reduce overall calorie intake A study published in the journal Appetite.

How to Safely Incorporate Soups for Weight Management

Use broth-based soup as a starter before meals to increase satiety and potentially reduce calorie intake. Make homemade soups to control sodium and include lean protein, healthy fats, and plenty of vegetables. This approach leverages the benefits of soup without the risks of a fad diet.

Frequently Asked Questions

The 21 day soup diet is not considered a safe, sustainable, or nutritionally complete long-term plan due to its restrictive nature, which can lead to nutrient deficiencies, fatigue, and muscle loss.

While the diet can cause rapid weight loss initially due to calorie restriction and water loss, much of this weight is often quickly regained. Long-term, sustainable weight loss is not typical with this diet.

The specific soups vary, but many versions focus on low-calorie, broth-based vegetable soups. Some variants, like the bone broth diet, also include bone broth as a primary component.

Yes, severe calorie restriction over an extended period can cause the body to slow down its metabolism to conserve energy. This can make it harder to maintain weight loss later.

No, a 21 day soup diet is not nutritionally balanced. It lacks sufficient protein, healthy fats, and other essential vitamins and minerals found in a varied diet.

The 21 day bone broth diet is a popular variant that combines a Paleo-style diet with intermittent fasting involving bone broth. It is more specific than a general soup diet but shares the same restrictive principles.

A more sustainable alternative involves incorporating healthy, nutrient-dense soups into a balanced diet that includes a variety of whole foods, lean proteins, healthy fats, and whole grains.