What happens if I only eat eggs for 7 days?

October 22, 2025 •

3 min read

Overly restrictive mono diets are generally unsustainable and can lead to nutrient deficiencies. So, what happens if I only eat eggs for 7 days, and are the potential benefits of this short-term approach worth the associated health risks and discomfort?

Quick Summary

A 7-day egg-only diet, or 'egg fast,' can cause rapid water weight loss due to its low-carb nature, potentially triggering ketosis. It leads to nutritional deficiencies, side effects like constipation, and is not a sustainable weight-loss solution.

Key Points

Initial Weight Loss: Any initial weight lost will likely be water weight and quickly regained once normal eating resumes.
Nutrient Deficiencies: An all-egg diet is severely deficient in fiber, Vitamin C, and complex carbohydrates, among other vital nutrients.
Common Side Effects: Expect symptoms like constipation, fatigue, headaches, irritability, and potentially 'keto flu' as your body adapts.
Unsustainable and Boring: The diet is monotonous and difficult to stick to, often leading to rebound weight gain and a strained relationship with food.
Risks for Certain Groups: Individuals with kidney or heart disease, as well as pregnant women, should avoid this diet entirely.
Promotes Unhealthy Habits: Fad diets like this one do not teach sustainable eating patterns and are not a long-term solution for weight management.

The Immediate Effects: Days 1-3

During the first few days of eating only eggs, your body undergoes significant changes. Due to the high protein and fat content of eggs and the complete absence of carbohydrates, your body will transition into a state of ketosis. This metabolic state uses fat stores for energy instead of glucose. For many, this can lead to an initial period of rapid water weight loss, as the body uses up its stored glycogen.

The 'Keto Flu'

As your body adapts to this new fuel source, you may experience 'keto flu' symptoms. These can include:

Headaches
Irritability
Fatigue
Nausea
Poor mental function

While eggs are very filling due to their high protein content, the sheer monotony of eating the same food can lead to intense food cravings and mental strain.

The Mid-Week Reality: Days 4-7

By the second half of the week, the initial boost of energy for some wears off, replaced by the reality of an unbalanced diet. Critical nutritional deficiencies begin to manifest, and the lack of fiber from fruits, vegetables, and grains can lead to digestive issues.

Nutritional Deficiencies and Risks

An egg-only diet, even for just 7 days, is severely lacking in essential nutrients. A large egg contains many vitamins and minerals, but it is not a complete food source. Here is a list of key nutrients you would be missing:

Fiber: Absent in eggs, crucial for healthy digestion and preventing constipation.
Vitamin C: Eggs contain virtually none, a critical nutrient for the immune system and skin health.
Phytochemicals and Antioxidants: Found abundantly in fruits and vegetables, which are completely excluded.
Calcium: An egg contains only about 24mg of calcium, far short of daily requirements.
Complex Carbohydrates: Necessary for sustained energy and brain function.

This nutritional imbalance can cause or worsen feelings of fatigue, dizziness, and low energy as the week progresses.

Comparison: All-Egg Diet vs. Balanced Diet for Weight Loss


Feature	7-Day All-Egg Diet	Sustainable, Balanced Diet
Nutrient Variety	Very low; deficient in fiber, Vitamin C, and complex carbs.	High; includes all food groups for complete nutrition.
Weight Loss	Initial rapid water weight loss is common; minimal long-term fat loss.	Gradual, steady, and sustainable fat loss over time.
Weight Regain	High risk of rebound weight gain once normal eating resumes.	Low risk; focuses on establishing long-term healthy habits.
Side Effects	Constipation, fatigue, headaches, bad breath, irritability.	Few to none; promotes overall wellness.
Sustainability	Very low; boredom and cravings make it hard to maintain.	High; flexible and adaptable to personal preferences.
Health Risks	Potential for nutrient deficiencies and other health issues, especially for those with pre-existing conditions.	Minimal; supervised diets reduce risks and improve health outcomes.

What to Expect After the 7 Days

Once you stop the egg-only diet, it's highly likely that any weight you lost, primarily water weight, will return quickly. The restrictive nature of the diet does not teach you sustainable eating habits. Instead, it can disrupt your relationship with food and slow down your metabolism, making future weight loss more challenging. The best approach is to reintroduce a variety of nutritious whole foods slowly, focusing on fiber, healthy carbs, and diverse protein sources to restore a balanced nutrient intake.

Conclusion: Is the Egg-Only Diet Worth It?

While the prospect of quick weight loss is tempting, the verdict on an egg-only diet is clear: the health risks outweigh the minimal, short-term benefits. Nutrition experts do not recommend mono-diets due to their highly restrictive and nutritionally imbalanced nature. For lasting, healthy results, focus on a balanced and sustainable eating pattern that includes a variety of whole foods, coupled with regular physical activity. A consultation with a registered dietitian can provide personalized, safe guidance for achieving your health goals.

For more information on balanced eating and sustainable weight loss, consult resources from reputable health organizations like the National Institutes of Health.

Frequently Asked Questions

No, an egg-only diet is not considered safe or healthy. While a week may not cause severe harm for all healthy individuals, it is highly restrictive and poses risks like nutritional deficiencies and potential health complications for certain people.

Most of the weight lost on this diet is temporary water weight, not sustainable fat loss. People may lose a few pounds quickly due to calorie and carb restriction, but this is usually regained after resuming a regular diet.

Common side effects include fatigue, headaches, constipation due to lack of fiber, nausea, and irritability. These are often linked to a metabolic shift into ketosis and severe nutrient restriction.

The relationship between dietary cholesterol and blood cholesterol is complex. While eggs contain cholesterol, recent guidelines have relaxed limits. However, consuming large quantities of eggs on a restrictive diet could still pose a risk, especially for those with existing cardiovascular issues.

No, the diet is not sustainable. Its highly restrictive nature, nutrient gaps, and monotony make it difficult to follow for more than a few days. Sustainable weight loss requires a balanced diet and long-term healthy habits.

You will be critically deficient in fiber, Vitamin C, calcium, complex carbohydrates, and many antioxidants found in plant-based foods. Eggs alone cannot provide all the essential nutrients your body needs.

Healthier alternatives include balanced eating patterns like the Mediterranean or DASH diet, which focus on a variety of whole foods, lean protein, and fiber. Consulting a dietitian is recommended for a personalized, sustainable plan.