What's it called when you only eat eggs?

December 5, 2025 •

4 min read

Although not a formally recognized term, the practice of exclusively eating eggs is a form of a mono diet, while a shorter, more popular version is known as the keto egg fast. A mono diet, by definition, involves consuming only a single food item for an extended period, which can lead to significant nutritional deficiencies. The highly restrictive and often unsustainable nature of these diets makes them controversial among health professionals, who typically recommend a balanced, varied eating pattern.

Quick Summary

The practice of eating only eggs is a mono diet or, more specifically, a keto egg fast, a short-term, low-calorie fad diet popular within keto circles. This article delves into the potential quick weight loss and nutrient benefits, but also the serious risks of nutritional imbalance and sustainability issues associated with this restrictive eating plan.

Key Points

Egg Fast: A specific, short-term version of a low-carb diet involving primarily eggs, cheese, and fat, often used to jump-start ketosis.
Mono Diet: A more extreme version where a person eats only one type of food, in this case, only eggs and water, which is highly restrictive.
Nutritional Gaps: Both the mono diet and egg fast lack essential nutrients like fiber, Vitamin C, and calcium, leading to deficiencies over time.
Unstable Weight Loss: Any initial rapid weight loss is typically water weight and not sustainable, often resulting in rebound weight gain.
Prioritize Balance: Health experts strongly advise against such restrictive plans and instead recommend a balanced diet with a variety of food groups for sustainable health.
Medical Consultation: Always consult a doctor or registered dietitian before starting any restrictive diet, especially if you have underlying health conditions.

Understanding the 'Egg-Only' Diet Phenomenon

Eating an egg-centric diet, or even an egg-only diet, has gained traction in recent years, particularly in niche diet communities. This approach is not a long-term, medically sound nutritional plan but rather a short-term, restrictive diet. While some people may use the terms interchangeably, there are subtle differences between an 'egg fast' and a true mono diet.

The Mono Diet: Eating Only Eggs

A pure egg mono diet is an extreme version of restrictive eating where a person consumes only hard-boiled eggs and water for a specified period, often marketed for rapid weight loss. This plan completely eliminates all other food groups, such as fruits, vegetables, and whole grains, making it nutritionally incomplete. Supporters of this approach often cite rapid initial weight loss, but this is largely due to severe calorie restriction and water weight loss rather than sustainable fat loss. Prolonged adherence to this type of mono diet can lead to significant nutrient deficiencies and potential health complications.

The Keto Egg Fast

The keto egg fast is a more common and slightly less extreme variant, used primarily by those following a ketogenic diet. This plan typically involves eating eggs, along with small amounts of cheese and healthy fats (like butter or olive oil), for three to five days. The goal is to jump-start ketosis or break through a weight-loss plateau. While still highly restrictive, the addition of fats and cheese provides a few more nutrients and calories than a pure egg mono diet. However, it still lacks the dietary fiber, vitamins, and minerals found in a balanced diet.

Potential Benefits (Short-Term) of an Egg-Based Diet

High in Protein: Eggs are a complete protein source, containing all nine essential amino acids. This can promote satiety and help preserve muscle mass during a period of calorie restriction.
Nutrient-Dense: Eggs are packed with nutrients like choline, vitamin D, selenium, and B vitamins. However, relying solely on them creates significant nutritional gaps.
Promotes Satiety: The high protein and fat content in eggs help individuals feel full for longer, which can reduce overall calorie intake.

Significant Risks and Drawbacks (Long-Term)

Nutrient Deficiencies: An egg-only diet lacks essential nutrients like fiber, vitamin C, calcium, and complex carbohydrates. Fiber is crucial for digestive health, and its absence can lead to constipation.
Unsustainable Weight Loss: The rapid weight loss experienced on these fad diets is not maintainable. Once a normal diet is resumed, the weight is likely to return, an effect known as "yo-yo dieting".
Potential Health Complications: Overly restrictive diets can cause side effects such as fatigue, headaches, irritability, and digestive issues. While a concern about egg cholesterol has been debated, experts still recommend a balanced diet and caution against excessive intake, especially for those with certain genetic conditions or a history of heart disease.
Developing an Unhealthy Relationship with Food: The highly restrictive nature of these diets can foster unhealthy eating habits and negative associations with food, potentially triggering disordered eating patterns.

Egg-Based Diets vs. Balanced Nutrition


Feature	Egg-Based Fad Diets (Mono/Fast)	Balanced, Sustainable Diet
Food Variety	Highly restrictive, limited to eggs and a few other items.	Broad variety of fruits, vegetables, whole grains, and lean proteins.
Nutrient Completeness	Deficient in many key vitamins, minerals, and fiber.	Provides all essential vitamins, minerals, and fiber for optimal health.
Weight Loss	Rapid but unsustainable, often water weight.	Gradual and sustainable fat loss, promoting healthy habits.
Health Impact	Short-term fixes with potential side effects; not medically recommended long-term.	Builds long-term health, supports metabolism, and provides sustained energy.
Long-Term Success	High risk of rebound weight gain and poor adherence.	High adherence and maintenance rates; fosters a positive relationship with food.

Conclusion: Prioritizing Health Over Trends

While the prospect of quick results from eating only eggs can be enticing, this practice is categorized as a fad diet and is not a healthy, sustainable, or medically recommended approach to weight management. Whether it's a pure egg mono diet or a keto egg fast, the restrictive nature inevitably leads to nutritional imbalances and potential health risks. True, lasting weight loss and optimal health are achieved through a balanced diet incorporating a wide variety of nutritious foods, combined with a healthy lifestyle. Before embarking on any restrictive eating plan, it is crucial to consult a healthcare professional. For those who enjoy eggs, incorporating them into a well-rounded diet, such as the Mediterranean diet, is a much safer and more beneficial strategy for long-term well-being. You can learn more about balanced eating from reliable sources, such as the Dietary Guidelines for Americans.

Frequently Asked Questions

No, it is not safe to eat only eggs for an extended period. This practice, known as an egg mono diet, is highly restrictive and leads to deficiencies in vital nutrients like fiber and vitamin C, potentially causing health complications.

A mono egg diet means eating only eggs and water, while an egg fast (or keto egg fast) is a slightly less restrictive, short-term diet that includes eggs, some cheese, and healthy fats, typically lasting only a few days.

You might lose weight quickly on an egg-only diet due to severe calorie restriction and water loss, but this weight loss is not sustainable. As soon as you return to normal eating patterns, the weight is likely to be regained.

By eating only eggs, you would miss crucial nutrients such as dietary fiber, which is important for digestion, as well as vitamin C, calcium, and complex carbohydrates.

Yes, risks include fatigue, headaches, constipation due to lack of fiber, and potential nutrient deficiencies. It is not recommended for individuals with specific health concerns, such as high cholesterol.

No, most health professionals do not recommend the keto egg fast. They emphasize that any restrictive fad diet, while potentially offering temporary results, is not a healthy, long-term solution for weight loss or nutritional balance.

A healthier, more sustainable alternative is a balanced diet that includes a variety of food groups, such as lean proteins (including eggs), fruits, vegetables, whole grains, and healthy fats, along with regular exercise.