Is One Meal a Day or Fasting Better for Your Health?

December 22, 2025 •

3 min read

According to a 2023 study published in the Journal of the Academy of Nutrition and Dietetics, skipping meals and shorter meal intervals were associated with increased mortality risk. When comparing one meal a day or fasting, this highlights the crucial difference between a balanced eating pattern and an extreme restriction.

Quick Summary

This article compares the benefits, risks, and sustainability of the One Meal a Day (OMAD) diet with other forms of intermittent fasting (IF). It discusses metabolic effects, potential health risks, and why less restrictive IF methods are often a safer and more sustainable long-term choice for most individuals.

Key Points

OMAD is an extreme fasting method: Eating one meal a day is an intense form of intermittent fasting, restricting all calorie intake to a 1-2 hour window, unlike more flexible methods.
Sustainability and risks favor less extreme fasting: Most people find OMAD difficult to sustain long-term and face higher risks of nutrient deficiencies, extreme hunger, and binge eating compared to other IF protocols.
Less restrictive IF offers similar benefits: Methods like 16:8 provide comparable benefits for weight loss, insulin sensitivity, and metabolic health with fewer risks and greater sustainability.
Food quality is more important than timing: Regardless of the fasting schedule, a nutritious, whole-food-based diet is essential for achieving long-term health benefits.
Consult a professional before starting: Before attempting a restrictive diet like OMAD, especially if you have underlying health conditions, always consult a healthcare provider.
OMAD may increase long-term mortality risk: A 2023 study found that eating one meal a day was associated with an increased risk of all-cause and cardiovascular disease mortality.

One Meal A Day (OMAD) vs. Intermittent Fasting

For many, the terms one meal a day (OMAD) and intermittent fasting are used interchangeably, but there are important distinctions. OMAD is an extreme form of intermittent fasting (IF) that compresses all daily calories into a single 1-2 hour eating window, fasting for the remaining 22-23 hours. Intermittent fasting, by contrast, encompasses various patterns that cycle between periods of eating and fasting, such as the popular 16:8 method which allows an 8-hour eating window.

While all forms of IF leverage the body's metabolic switch from burning glucose to burning stored fat, the intensity and duration of the fasting period significantly impact outcomes. OMAD’s prolonged daily fast can lead to rapid weight loss by creating a large caloric deficit, but it also presents greater risks and sustainability challenges compared to less restrictive IF regimens.

The Allure and Risks of the OMAD Diet

The appeal of OMAD is its simplicity, but it comes with significant drawbacks. While some benefits like fat loss and increased alertness are reported, a 2023 study linked eating one meal a day to a higher risk of all-cause and cardiovascular disease mortality. Additionally, OMAD makes it difficult to meet nutritional needs, can lead to extreme hunger and bingeing, cause low energy, and potentially disrupt hormones, especially in women.

The Flexibility and Benefits of Intermittent Fasting

Less restrictive IF methods like 16:8 or 18:6 offer similar metabolic benefits to OMAD with fewer risks. These methods help with appetite management, weight loss, and insulin sensitivity, and are generally more sustainable and easier to integrate into daily life.

Comparison: OMAD vs. General Fasting (e.g., 16:8)


Feature	One Meal A Day (OMAD)	Intermittent Fasting (e.g., 16:8)
Eating Window	1-2 hours	6-8 hours
Fasting Period	22-23 hours	16-18 hours
Difficulty & Sustainability	High; often unsustainable long-term due to extreme restriction and risks of bingeing and nutrient deficiency.	Moderate; more adaptable and easier to maintain long-term for most individuals.
Weight Loss Potential	High initial weight loss, but rebound weight gain is a significant risk.	Effective for weight loss comparable to traditional dieting; less risk of rebound.
Metabolic Benefits	Potential improvements in insulin sensitivity, but can also cause adverse effects like increased cholesterol and blood pressure in some cases.	Proven to improve insulin sensitivity, reduce blood pressure, and lower cholesterol.
Risk of Nutrient Deficiency	High; very difficult to meet all nutritional needs in one sitting.	Lower; easier to achieve a balanced diet across several meals.
Impact on Muscle Mass	Challenging to maintain or build muscle due to inadequate protein and calorie intake.	Easier to support muscle maintenance, especially when combined with resistance training and proper protein intake.

Making the Right Choice for Your Body

Choosing between one meal a day or a more moderate intermittent fasting protocol requires considering your health, goals, and lifestyle. Sustainability is crucial for healthy weight management.

Consider Your Personal Health

Consulting a healthcare professional before starting any restrictive regimen like OMAD is essential, especially with existing conditions or a history of eating disorders. A less restrictive approach like 16:8 is often a safer starting point for healthy individuals, allowing for gradual adaptation.

Focus on Quality, Not Just Timing

Nutrient-dense whole foods are vital regardless of the fasting schedule. Prioritize lean proteins, healthy fats, complex carbohydrates, and plenty of produce during your eating window to ensure nutritional needs are met and support long-term health.

The Importance of Sustainability

OMAD's low sustainability rate highlights the need for a plan you can maintain long-term. Less extreme IF offers a better balance for many, promoting a healthier relationship with food and preventing cycles of restrictive dieting.

Conclusion

Less extreme intermittent fasting methods are generally better than one meal a day due to lower risks, greater sustainability, and similar metabolic benefits. A personalized, balanced approach focusing on food quality within a moderate fasting window is often the safest and most effective long-term strategy.

For more in-depth information on the metabolic impacts of different eating patterns, consult resources from authoritative health institutions like Johns Hopkins Medicine.

Note: Before beginning any new dietary regimen, especially one involving prolonged fasting, always consult a qualified healthcare professional.

Benefits of Intermittent Fasting (General IF, not OMAD)

Intermittent fasting offers benefits such as promoting the use of stored fat for energy, improving insulin sensitivity, potentially enhancing mental clarity, and contributing to better heart health by helping to lower blood pressure, improve cholesterol, and reduce inflammation. It can also simplify meal planning.

Frequently Asked Questions

No, OMAD is an extreme type of intermittent fasting. While both involve periods of not eating, OMAD confines all daily calories to a very small window (typically 1-2 hours), whereas other IF methods, like 16:8, allow for a larger eating window.

Both can lead to weight loss, but less-extreme intermittent fasting is generally considered safer and more sustainable long-term. While OMAD may cause rapid initial weight loss, less restrictive IF offers similar fat loss over time without the high risks of nutrient deficiency and rebound weight gain.

No, the OMAD diet is not recommended for everyone. It can be particularly risky for individuals with a history of eating disorders, diabetes, pregnant or breastfeeding women, and older adults. A healthcare professional should always be consulted before starting.

Building and maintaining muscle mass is very challenging on the OMAD diet. It is difficult to consume enough protein and calories in a single meal to support muscle growth and repair, which can lead to loss of lean body mass.

Common side effects include extreme hunger, fatigue, irritability, headaches, dizziness, and low energy. The extended fasting period can also lead to nutrient deficiencies and potential hormonal disruptions.

During your eating window, it's best to prioritize a nutrient-dense diet rich in whole foods, including lean protein, healthy fats, fiber-rich vegetables, and complex carbohydrates. The timing of your meals should not be an excuse to consume low-quality, processed foods.

During a fast, you can consume calorie-free beverages such as water, black coffee, or plain herbal tea. Anything with calories, including milk or sweeteners, will break the fast.