What Happens if I Eat Only Eggs for a Week?

November 22, 2025 •

4 min read

While eggs are a powerhouse of nutrients and protein, a diet consisting solely of them for a week is a short-term, unsustainable practice that can lead to health complications. The appeal of rapid weight loss from such a restrictive plan often overshadows the risks of severe nutritional deficiencies and other negative health effects.

Quick Summary

Eating only eggs for a week may lead to initial weight loss due to calorie restriction, but it causes significant nutrient deficiencies, including a total lack of fiber and vitamin C. This restrictive diet can result in short-term side effects like constipation and fatigue, and the lost weight is often quickly regained.

Key Points

Nutrient Deficiencies: An egg-only diet is completely devoid of fiber and lacks critical vitamins like C, leading to digestive issues and a weakened immune system.
Initial Weight Loss is Mostly Water: Any rapid weight reduction is likely water weight loss from carb restriction, not sustainable fat loss, and is often quickly regained.
Digestive Problems are Inevitable: Without fiber, constipation and other gastrointestinal distress are highly probable within the first week.
Fatigue and 'Keto Flu': The severe restriction of carbohydrates can trigger side effects like fatigue, headaches, and nausea as your body adapts.
Rebound Weight Gain is Common: The unsustainability of the diet often leads to binge eating and the regaining of lost weight, sometimes more, once normal eating resumes.
Risk of High Cholesterol: While individual reactions vary, high intake of dietary cholesterol can be a concern, especially for those with existing risk factors.
Unsustainable and Psychologically Taxing: A restrictive monodiet is hard to adhere to, can cause food cravings, and may create an unhealthy relationship with food.

The Lure of a Short-Term Egg-Only Diet

The idea of a simple, quick-fix diet is tempting, and few things are simpler than eating only eggs. Proponents of such restrictive plans, like the egg fast, are often chasing rapid weight loss by forcing the body into a calorie deficit. Eggs are nutrient-dense, providing high-quality protein and healthy fats, which can promote satiety and reduce overall calorie intake in the short run. For a few days, this can lead to a quick drop on the scale, but it's largely due to a loss of water weight rather than sustainable fat loss. The body quickly adapts to the low-carbohydrate intake, shifting into a state of ketosis, where it burns fat for energy. However, even with the apparent simplicity, the reality of a single-food diet is far more complex and risky than many anticipate.

The Nutritional Void and Physical Side Effects

Despite being a nutritional powerhouse, eggs cannot meet all of the body's needs alone. A diet consisting solely of eggs will create significant nutritional gaps that manifest through a range of uncomfortable and potentially harmful side effects. A primary concern is the complete lack of dietary fiber, a nutrient critical for digestive health. Without fiber, constipation is a near-certainty. A one-week egg-only diet also excludes a host of vitamins and minerals found in fruits, vegetables, and whole grains, most notably vitamin C, which is absent from eggs. This deficiency can weaken the immune system and cause a general feeling of being unwell. The sudden and extreme change in eating habits can also trigger a temporary state known as the 'keto flu,' with symptoms like fatigue, headaches, and nausea.

The Short-Term vs. Long-Term Health Outcomes


Feature	Eating Only Eggs for a Week (Short-Term)	Balanced, Sustainable Diet (Long-Term)
Weight Loss	Rapid initial weight loss, mostly water weight.	Gradual, sustainable fat loss.
Satiety	High protein keeps you feeling full temporarily.	Balanced macronutrients ensure consistent fullness.
Nutrient Intake	Severe deficiencies in fiber, vitamin C, and other vital micronutrients.	All essential vitamins, minerals, and fiber are consumed.
Digestive Health	Likely to cause constipation and other issues due to zero fiber.	Promotes regular and healthy digestion.
Energy Levels	Initial energy boost may be followed by fatigue from low calories and carbs.	Provides steady, consistent energy throughout the day.
Dietary Variety	Highly restrictive and boring, leading to food cravings and fatigue.	Offers a wide array of foods and flavors, promoting long-term adherence.
Metabolism	Long-term energy restriction can lower metabolic rate, making future weight loss harder.	Supports a healthy metabolic rate through balanced nutrition.

Beyond the Single Week: The Unintended Consequences

While a week might seem like a manageable period, it can set the stage for unhealthy habits and rebound weight gain. The severe calorie restriction and absence of variety make an egg-only diet difficult to sustain, leading many to binge-eat once it's over. This can trigger a "yo-yo dieting" effect, with the lost weight quickly returning, and sometimes more, as the body aggressively stores calories from the newfound food intake. The psychological toll should also not be underestimated. The extreme restriction can foster a negative relationship with food and may be particularly harmful for those with a history of disordered eating. For individuals with pre-existing conditions, such as kidney disease or high cholesterol, an exclusively egg diet can pose serious risks and should be avoided.

A Better Path: Sustainable and Balanced Nutrition

Eating eggs can be a healthy part of a balanced diet, but they should never be the sole source of nutrition. For those seeking weight loss or better health, a more evidence-based approach is always preferable. Sustainable, long-term health is achieved through a varied diet rich in whole foods, including a mix of lean proteins, fruits, vegetables, whole grains, and healthy fats. Adopting an eating pattern like the Mediterranean diet offers proven benefits without the risks and discomfort of a restrictive monodiet. Adding exercise and mindful eating habits further solidifies the foundation for lasting health. A discussion with a healthcare professional can also help develop a personalized, safe, and effective nutrition plan that incorporates eggs in a healthy moderation. For more on building healthy dietary habits, consider resources like the Dietary Guidelines for Americans (DietaryGuidelines.gov).

Conclusion

Eating only eggs for a week is a potentially harmful and unsustainable approach to dieting. While it might yield temporary weight loss, the cost to your health is significant, including severe nutrient deficiencies, digestive problems, and a high likelihood of rebound weight gain. Eggs are a valuable, nutritious food, but moderation and variety are key to unlocking their benefits. The best path to health and weight management is a balanced, whole-foods-based diet that can be maintained for a lifetime.

Frequently Asked Questions

Yes, you will likely lose weight due to the extremely low calorie intake. However, most of this weight will be water loss from carbohydrate restriction, not sustainable fat loss, and you will likely regain it once you stop the diet.

The most significant risks include a complete lack of dietary fiber, leading to constipation, and a deficiency in vitamin C, which can weaken your immune system.

No, it is not safe for everyone. Individuals with conditions like kidney disease, high cholesterol, or a history of eating disorders should avoid such restrictive diets. Pregnant or breastfeeding women, children, and teenagers should also abstain.

Without fiber, the digestive system slows down considerably. This can lead to severe constipation, bloating, and other forms of gastrointestinal discomfort.

While eggs are an excellent source of high-quality protein and many nutrients like choline, they are not a complete source. They lack fiber and vitamin C, and you'll miss out on numerous other vitamins and antioxidants found in a varied diet.

You may experience an initial energy dip or 'keto flu' as your body adapts to a low-carb intake. Low overall calories and a lack of variety can lead to fatigue and general malaise.

No, dieticians generally do not recommend it. The restrictive nature can set up unhealthy eating patterns and lead to a cycle of rebound weight gain. Sustainable, balanced eating is a better foundation for long-term health.