Is it bad to only eat once or twice a day?

December 1, 2025 •

3 min read

According to a 2017 study involving over 50,000 adults, eating one or two meals daily was associated with a lower body mass index (BMI) compared to eating three. However, the question of whether it's bad to only eat once or twice a day involves far more than just weight, encompassing metabolic health, energy levels, and potential risks.

Quick Summary

Eating one or two meals daily can offer benefits like weight loss and simplified meal planning, often associated with intermittent fasting protocols. Yet, potential downsides include nutrient deficiencies, low energy, and increased risk for certain health issues. The overall impact is highly individual and depends heavily on diet quality and medical history.

Key Points

Not an Extreme Diet: For healthy individuals, eating twice a day is a moderate form of intermittent fasting.
Weight Management Benefits: Reducing meal frequency can create a calorie deficit, promoting weight loss and potential improvements in BMI.
Metabolic Health Improvements: Longer fasting windows can help stabilize blood sugar and improve insulin sensitivity.
Focus on Nutrient Density: Prioritize nutrient-dense, whole foods to avoid deficiencies.
Not for Everyone: This approach is not suitable for certain groups, including those who are pregnant or have specific health conditions.
Gradual Adaptation is Key: Transition slowly into a reduced meal schedule.

For many years, the conventional wisdom suggested that three meals a day was the healthiest approach to eating. However, the rise of intermittent fasting has challenged this notion, with many people adopting one-meal-a-day (OMAD) or two-meal-a-day diets. The truth is that the effect of eating only once or twice a day isn't a simple 'good' or 'bad' answer; it's a complex issue with both potential benefits and significant risks that depend heavily on individual factors and the nutritional quality of the meals consumed.

The Potential Benefits of Reduced Meal Frequency

For some, reducing the number of meals per day can be a highly effective strategy for weight management and overall health, often functioning as a form of time-restricted eating (TRE).

Aids in weight loss: Eating one or two meals daily can lead to a lower overall calorie intake, which is essential for weight loss. Studies have shown reduced BMI and body fat in individuals who eat less frequently.
Improves metabolic markers: Longer fasting periods can improve insulin sensitivity and glucose metabolism, potentially lowering the risk of type 2 diabetes and improving heart health markers.
Enhances mental clarity and focus: Some individuals report improved mental clarity, possibly linked to more stable blood sugar levels.
Boosts digestive health: Longer breaks for the digestive system can improve gut health and reduce symptoms like bloating.
Simplifies life: A two-meal-a-day approach can offer increased convenience and free up time.

The Risks and Downsides to Consider

Despite the benefits, eating only once or twice a day carries significant risks and is not suitable for everyone.

Nutrient deficiencies: It can be challenging to get all necessary nutrients in one or two meals, potentially leading to deficiencies.
Risk of low energy and fatigue: Irregular energy supply can cause blood sugar fluctuations, leading to fatigue and irritability.
Increased cholesterol and blood pressure: Some studies suggest extreme meal restriction may increase 'bad' cholesterol and blood pressure.
Potential for disordered eating: Restrictive patterns can trigger or worsen disordered eating tendencies.
Impact on lean muscle mass: Extremely restrictive fasting may lead to the loss of lean body mass.
Health concerns for specific groups: This pattern is not recommended for pregnant/breastfeeding women, children, teens, older adults, or those with certain medical conditions like diabetes or a history of eating disorders.

Comparison of Meal Frequencies


Feature	Eating Once a Day (OMAD)	Eating Twice a Day (TRE)	Eating Three+ Times a Day
Weight Management	Can lead to significant calorie deficit and fast weight loss, but with a higher risk of rebound weight gain.	Can create a sustainable calorie deficit with consistent energy and nutrient intake.	Easier to maintain balanced nutrition and prevent overeating, but requires more planning.
Nutrient Intake	High risk of deficiencies; careful planning is essential.	More manageable for balanced nutrient intake.	Easiest to achieve a complete nutritional profile.
Energy Levels	High risk of energy crashes and irritability.	More stable energy throughout the day.	Provides a consistent and steady energy supply.
Digestion	Can cause indigestion with one large meal.	Provides longer rest for the digestive system, improving gut health.	Regular intake can be taxing if meals are large or frequent.
Sustainability	Difficult for most long-term.	More sustainable and flexible option.	Most culturally and socially accepted, highly sustainable.

What to Eat for Optimal Health

If you eat only one or two meals a day, focus on nutrient-dense whole foods to prevent deficiencies.

Lean Proteins: Essential for satiety and muscle maintenance.
Healthy Fats: Help with fullness and provide essential fatty acids.
High-Fiber Foods: Support digestive health and provide sustained energy.
Hydration: Drink plenty of water; black coffee or unsweetened tea is also an option.

How to Get Started with a Reduced Meal Schedule

A gradual approach is recommended to allow your body to adapt. Start by slowly shortening your eating window. Listen to your body and consult a healthcare professional before making drastic changes, especially with pre-existing conditions.

Conclusion

Is it bad to only eat once or twice a day? It depends on your health, diet quality, and sustainability. While there are potential benefits like weight loss and improved metabolic health, there are also risks, particularly with extreme patterns like OMAD. A two-meal-a-day pattern is often a more moderate and sustainable form of intermittent fasting. The nutritional value of your food is most important, regardless of meal frequency. Consult a health professional for personalized guidance.

Frequently Asked Questions

For most people, eating only one meal a day (OMAD) is not a sustainable long-term strategy. It is an extreme form of intermittent fasting with higher risks of nutrient deficiencies, fatigue, and potential for disordered eating. Professional guidance is essential.

Yes, eating twice a day can help with weight loss by naturally reducing your total calorie intake. This can create the calorie deficit necessary for weight loss.

Significant risks include potential nutrient deficiencies, low energy levels, dizziness, and irritability due to blood sugar fluctuations. It can be particularly dangerous for individuals with certain health conditions.

Focus on making your one or two meals as nutrient-dense as possible. Prioritize a wide variety of whole foods, including lean proteins, healthy fats, high-fiber vegetables, fruits, and whole grains.

Avoid this pattern if you are pregnant or breastfeeding, a child, teen, older adult, or have a history of eating disorders. Consult a doctor if you have an underlying medical condition, especially diabetes.

While meal frequency can influence health, the quality of your diet is far more important. Eating two nutrient-dense meals is healthier than three unhealthy meals.

TRE is an intermittent fasting pattern where you eat within a specific window, typically 8-10 hours, and fast for the rest of the day. Eating two meals a day fits into this, allowing for longer fasting periods.