What Would Happen if You Ate Soup for a Week? An Analysis of a Fad Nutrition Diet

October 16, 2025 •

4 min read

According to nutrition experts, most of the rapid weight loss seen on highly restrictive diets, including those centered on soup, is primarily water weight rather than fat. Delving into what would happen if you ate soup for a week reveals a complex picture of both immediate effects and potential health risks.

Quick Summary

A week-long soup diet may induce rapid, short-term weight loss but often leads to nutrient deficiencies, a slowed metabolism, and eventual weight regain. It is not a sustainable or nutritionally balanced eating plan for lasting health.

Key Points

Rapid Water Weight Loss: Eating only soup for a week can lead to a quick drop on the scale, but this is largely due to losing water and stored glycogen, not significant body fat.
High Risk of Deficiencies: A soup-only diet is unsustainable and often lacks sufficient protein, healthy fats, and essential vitamins and minerals, leading to potential health issues.
Metabolic Slowdown: Severely restricting calories signals starvation to the body, which responds by lowering its metabolic rate and making long-term weight management more difficult.
Unsustainable and Risky: The monotony of eating only soup can lead to irritability and an unhealthy relationship with food, often resulting in a rebound effect where lost weight is quickly regained.
Healthier Approach: The healthiest strategy is to incorporate a variety of nutrient-dense, homemade soups into a balanced diet, rather than relying on a restrictive, week-long plan.

The Allure of the Week-Long Soup Diet

For decades, various forms of the 'soup diet'—such as the cabbage soup diet or Sacred Heart diet—have circulated as quick fixes for shedding pounds. The premise is appealingly simple: fill up on low-calorie, liquid-based meals to create a significant calorie deficit. While this approach can lead to a quick drop on the scale, its effects are much more complex and often short-lived. A week dedicated exclusively to soup can have immediate impacts on your body, but it is critical to understand that these outcomes are largely unsustainable and carry significant health risks.

The Initial Experience: What to Expect

In the first couple of days of a soup-only diet, you will likely experience a rapid reduction in weight. This is a common phenomenon with very low-calorie diets and is primarily due to the loss of water weight and stored glycogen, not body fat. As the body uses up its glycogen stores, it also releases the water that was bound to it. This can give a powerful sense of accomplishment, but it's often a temporary effect that can be psychologically misleading.

Simultaneously, you may notice an increase in energy from the initial flush of a 'detox,' especially if moving from a diet high in processed foods. However, as the week progresses, this can quickly change. Homemade soups, particularly vegetable-based ones, are high in water and fiber, which contributes to a feeling of fullness and can aid digestion. This increased hydration and fiber intake can be a temporary benefit, but it does not compensate for the significant nutrient deficits that will soon follow.

The Risks and Nutritional Deficiencies of a Soup-Only Diet

The most significant drawbacks of eating only soup for an entire week revolve around nutritional imbalance and its impact on your metabolism. Even if you incorporate a variety of homemade, healthy soups, it is nearly impossible to meet your body's full range of dietary needs from liquids alone.

Macronutrient deficiencies: Without a sufficient intake of balanced proteins, healthy fats, and complex carbohydrates, your body can experience issues. A lack of protein can lead to muscle loss, as the body breaks down muscle tissue for energy once carb stores are depleted. Inadequate healthy fats can lead to hormonal disturbances and inflammation.
Micronutrient gaps: A soup-only diet can fail to provide essential vitamins and minerals, such as iron, calcium, and vitamins A, D, and B12. This can lead to serious health issues if continued for too long, including anemia and a weakened immune system.
Metabolic slowdown: A drastically reduced calorie intake signals to your body that it is in a state of starvation. In response, your body will lower its metabolic rate to conserve energy. This makes it harder to lose weight over time and can contribute to rapid weight regain once you return to your regular eating habits, a phenomenon known as the 'rebound effect'.
Fatigue and irritability: The low-calorie and low-carbohydrate nature of many soup diets can cause side effects like dizziness, weakness, headaches, and irritability. This is due to inadequate energy and blood sugar fluctuations.
High sodium intake: Relying on canned or pre-packaged soups can be detrimental due to their high sodium content. Excessive sodium can cause water retention, bloating, and increased blood pressure.

Comparing a Restrictive Soup Diet to a Balanced Approach


Feature	Restrictive Week-Long Soup Diet	Balanced Diet (Incorporating Soup)
Weight Loss	Rapid, primarily water and glycogen loss; often temporary.	Gradual and sustainable; focuses on fat loss.
Nutritional Profile	High risk of nutrient deficiencies (protein, fat, vitamins, minerals).	Varied and complete; meets all macronutrient and micronutrient needs.
Metabolic Impact	Can cause metabolic slowdown and rebound weight gain.	Supports a healthy metabolism and long-term weight management.
Sustainability	Very difficult to sustain; often leads to cravings and overeating.	Adaptable and enjoyable; promotes healthy long-term habits.
Energy Levels	Initial spike followed by fatigue, dizziness, and low energy.	Steady and consistent energy throughout the day.
Mental Health	Can lead to mood swings, irritability, and unhealthy food relationships.	Promotes a positive and healthy relationship with food.

Healthier Alternatives to a Full Week of Soup

Instead of restricting yourself to a single food group for an extended period, the healthiest and most sustainable approach is to incorporate nutritious, homemade soups into a balanced diet. This allows you to reap the benefits of increased vegetable intake and hydration without sacrificing essential nutrients.

Use healthy homemade broths: Start with homemade bone broth or vegetable broth, which provide vitamins, minerals, and collagen without excessive sodium.
Add lean protein: Incorporate lean proteins like shredded chicken, turkey, tofu, or legumes to maintain muscle mass and increase satiety.
Load up on fiber: Use a wide variety of vegetables, beans, and lentils to maximize your fiber intake, which is excellent for digestive health.
Include healthy fats: Add a source of healthy fat, such as avocado, nuts, seeds, or a drizzle of olive oil, to improve the absorption of fat-soluble vitamins and increase fullness.
Use soup as a meal component: Rather than making soup your only meal, use it as a low-calorie, nutrient-dense starter to your main meal to help you feel full faster and manage your overall calorie intake.

Conclusion: The Path to Sustainable Health

While a week-long soup diet may promise rapid results, the reality is that the weight loss is often temporary, and the method poses significant risks to your nutritional and metabolic health. The potential benefits, such as increased vegetable intake and hydration, can be achieved far more safely by simply including healthy, balanced soups as part of a varied and sustainable eating plan. Rather than engaging in a restrictive and monotonous short-term approach, focus on adopting long-term lifestyle changes that foster a positive relationship with food. Consulting a healthcare professional or registered dietitian before starting any restrictive diet is always the wisest course of action to ensure your eating habits are both effective and safe for your individual health needs. Learn more about sustainable weight management from reliable sources like Healthline.

Frequently Asked Questions

You will likely experience short-term weight loss due to the calorie restriction, but much of this is water weight and stored glycogen. It is not a sustainable method for long-term fat loss.

No, a diet consisting solely of soup is not nutritionally balanced. It often lacks adequate protein, healthy fats, and essential micronutrients, which can lead to deficiencies.

Health risks include muscle loss, metabolic slowdown, fatigue, dizziness, electrolyte imbalances, and potential nutritional deficiencies if followed for more than a few days.

While convenient, many canned soups are very high in sodium. Excessive sodium can cause water retention and is not healthy, especially for individuals with blood pressure concerns.

For most healthy individuals, doing a soup-only diet for a week is not likely to cause serious harm, but it is not recommended. It's crucial to consult a healthcare professional first, especially if you have pre-existing conditions.

When you drastically reduce your calorie intake, your body's metabolic rate can slow down to conserve energy. This can make it harder to maintain weight loss in the long run.

Incorporate healthy, homemade, and balanced soups (with protein, vegetables, and fiber) as part of a regular, varied diet. Use soup as a nutritious starter or meal component, not as your sole source of food.