Will I be okay if I only eat one meal a day?

November 30, 2025 •

3 min read

Research on the long-term effects of eating just one meal a day, known as OMAD, is limited, and most health professionals do not endorse it as a sustainable or safe strategy. Before adopting an eating pattern like OMAD, it's crucial to understand the potential consequences and determine if it is right for you.

Quick Summary

This article explores the one-meal-a-day (OMAD) diet, detailing how it works, its potential benefits for weight loss and metabolic health, and the considerable risks like nutrient deficiencies, muscle loss, and eating disorders. Key strategies for safe implementation and important contraindications are outlined.

Key Points

Risks May Outweigh Benefits: OMAD carries significant risks, including potential nutrient deficiencies, loss of muscle mass, and extreme hunger, which may outweigh its benefits.
Not a Long-Term Solution: Most health professionals do not recommend OMAD as a long-term or sustainable eating strategy due to its restrictive nature and potential for adverse effects.
Consult a Professional: Individuals, especially those with medical conditions like diabetes or a history of eating disorders, should consult a healthcare provider before considering OMAD.
Nutrient-Dense Meals are Critical: For those who pursue OMAD, careful planning is essential to pack all necessary macro- and micronutrients into one well-balanced meal.
Hydration is Non-Negotiable: Drinking plenty of water and other non-caloric beverages is vital to stay hydrated and manage hunger during the fasting period.
Safer Alternatives Exist: Less restrictive forms of intermittent fasting, such as the 16:8 method, and traditional calorie-controlled diets offer a more sustainable path to weight loss and improved health.
Adaptation is Needed: The body requires time to adjust to a new eating pattern, and starting gradually with shorter fasting windows can help minimize side effects like fatigue and irritability.

What is the OMAD Diet?

The One Meal a Day (OMAD) diet is an extreme form of intermittent fasting that restricts all daily calorie intake to a single, typically one-hour, eating window. The rest of the day—approximately 23 hours—is a fasting period where only non-caloric beverages are consumed. The core principle is that this prolonged fasting period pushes the body to deplete its glycogen stores and switch to burning stored fat for energy, a metabolic state known as ketosis.

Potential Benefits of Eating One Meal a Day

Proponents of the OMAD diet cite several potential advantages, though research specifically on this extreme method is often limited and mixed.

Weight Loss: OMAD can create a calorie deficit, which is the basis for weight loss. Studies suggest intermittent fasting can be effective for weight loss, often with results similar to simple calorie restriction.
Improved Metabolic Health: Fasting may lead to lower insulin levels and improved insulin sensitivity, aiding blood sugar regulation. This can help the body burn fat more effectively.
Increased Mental Clarity: Some individuals report better focus during fasting, potentially due to stable blood sugar and ketone production.
Simplicity: Eating only one meal simplifies meal planning and preparation.

Significant Risks of the OMAD Diet

Medical experts advise caution regarding OMAD due to potential risks.

Nutrient Deficiencies: Consuming all essential nutrients in one meal is challenging, potentially leading to deficiencies and long-term health issues.
Extreme Hunger: Prolonged fasting can increase hunger hormones, causing intense cravings and potentially unhealthy food choices or binge eating.
Fatigue: Irregular energy intake can cause fatigue, dizziness, irritability, and concentration difficulties. Low blood sugar is also a risk, especially for those with diabetes.
Loss of Lean Body Mass: Weight loss on OMAD may include muscle mass loss, negatively impacting metabolism and health.
Increased Cholesterol: Some studies show OMAD may increase total and LDL cholesterol, as well as blood pressure.

Comparison: OMAD vs. Less Restrictive Fasting


Feature	OMAD (One Meal a Day)	16:8 Intermittent Fasting	Traditional Diet (3 meals)
Fasting Window	23 hours	16 hours	Short or none
Eating Window	1 hour	8 hours	All day
Satiety	Intense hunger, risk of overeating	Less intense hunger, manageable	Regular, consistent feeding
Nutritional Intake	Difficult to meet all needs in one sitting	Easier to balance over 8 hours	Spreads intake throughout the day
Sustainability	Very difficult long-term; high dropout rates	Easier to sustain; fits most lifestyles	Highly sustainable for most
Risk of Bingeing	High risk due to extreme hunger	Lower risk; less restriction	Very low risk
Flexibility	Very rigid schedule	More flexible meal timing	Most flexible for social eating

Is Eating One Meal a Day Right for You?

OMAD is not a universally safe or sustainable option. A gradual approach to intermittent fasting, like the 16:8 method, is often recommended as a safer alternative. Consulting a healthcare professional is crucial before starting OMAD, especially with pre-existing conditions, to assess risks and create a personalized plan.

How to Structure a Nutritious OMAD Meal

Careful planning is essential to get adequate nutrients in one meal.

Prioritize Protein: Include lean protein for muscle mass and satiety.
Include Healthy Fats: Healthy fats provide energy and support hormone function.
Load Up on Fiber: Fill half your plate with vegetables and include fruits and whole grains.
Stay Hydrated: Drink plenty of water and non-caloric beverages throughout the day.

Conclusion

While OMAD can lead to weight loss and may offer some metabolic benefits, it carries significant risks, including nutrient deficiencies, muscle loss, and disordered eating patterns. It is an extreme form of intermittent fasting not suitable or sustainable for many, especially those with pre-existing health conditions. Less restrictive eating patterns or traditional calorie-reduction methods are often safer and more sustainable. Always consult a healthcare professional before starting a restrictive diet.

Frequently Asked Questions

No, OMAD is not safe for everyone. It is particularly risky for individuals who are pregnant, breastfeeding, children, older adults, people with a history of eating disorders, or those with underlying medical conditions like diabetes.

Yes, it is very difficult to consume all the necessary vitamins, minerals, and other nutrients from a single meal, which can lead to nutritional deficiencies over time.

There is a risk of losing lean muscle mass on the OMAD diet, especially if you are not consuming enough protein or are not engaging in resistance training.

Common side effects include intense hunger, irritability, fatigue, dizziness, headaches, and difficulty concentrating, especially during the initial adjustment period.

Yes, it can lead to weight loss by creating a calorie deficit. However, it is not necessarily more effective than other calorie-restriction methods and is generally not recommended as a sustainable long-term strategy.

To make your one meal as healthy as possible, focus on a balanced plate rich in lean protein, healthy fats, complex carbohydrates, and a wide variety of colorful, fiber-rich vegetables.

There is no consensus that OMAD is superior to less restrictive fasting methods like the 16:8. In fact, many health professionals advise against OMAD due to its extreme nature and potential for negative side effects.