What is the best time of day to eat one meal?

January 7, 2026 •

3 min read

A 2022 study in Frontiers in Physiology noted that participants eating one meal a day in the evening experienced significant reductions in body weight and fat mass. However, the specific timing can be highly individual, and understanding what is the best time of day to eat one meal depends on various factors, including your goals, lifestyle, and natural body clock.

Quick Summary

The ideal time for a single daily meal varies based on individual factors like metabolic health, digestion, and schedule. Early eating windows may improve metabolic markers, while later windows often align better with social lifestyles. Consistency and a nutrient-dense meal are critical regardless of the timing chosen.

Key Points

Align with your circadian rhythm: Eating earlier in the day (morning/afternoon) aligns better with your body's natural metabolic cycles and insulin sensitivity.
Evening meals prioritize lifestyle: An evening meal plan fits more easily with social gatherings and modern work schedules, promoting long-term sustainability.
Nutrient density is critical: Since all daily nutrients are consumed in one sitting, the meal must be dense in protein, fiber, and micronutrients to prevent deficiencies.
Consistency aids adaptation: Eating at the same time every day helps regulate hunger hormones and makes fasting periods more manageable as the body adapts.
OMAD is not for everyone: Individuals with specific health conditions, such as diabetes or a history of eating disorders, should avoid OMAD unless under strict medical supervision.
Start gradually: For newcomers, a gradual transition from less extreme fasting, like 16:8, can help the body adjust to longer fasting periods more comfortably.
Prioritize hydration: Staying hydrated with calorie-free beverages like water, black coffee, or herbal tea is crucial throughout the 23-hour fasting window.

The one-meal-a-day (OMAD) diet, an extreme form of intermittent fasting, has gained popularity for its potential benefits, including weight loss and improved metabolic health. The debate, however, centers on timing: is it better to eat in the morning or the evening? The answer is nuanced and depends on how your body responds and what you are trying to achieve.

Early Eating: Aligning with Your Circadian Rhythm

Aligning your eating schedule with your body's natural 24-hour cycle, or circadian rhythm, is a key consideration for many health experts. Research suggests that eating during the earlier, daylight hours may optimize your body's metabolic functions.

Potential Benefits of Morning/Afternoon OMAD

Studies suggest that eating earlier in the day may lead to improved insulin sensitivity and blood sugar response, as the body is more efficient at processing glucose during daylight hours. This timing may also enhance fat burning and lead to better digestion compared to eating late at night.

Evening Eating: The Lifestyle-Friendly Option

For many, an evening eating window is more practical, allowing for social dinners and aligning with the body's 'rest and digest' state in the late afternoon and early evening. While metabolic benefits might be less pronounced than with earlier eating, the social flexibility can make this approach more sustainable long-term.

What happens to your body when you eat one meal a day?

When following an OMAD schedule, your body undergoes several changes. You'll likely experience a metabolic shift where your body uses stored fat for energy (ketosis) after extended fasting. Hormonal changes, including the regulation of hunger hormones, can also occur. Extended fasting may activate autophagy, a cellular repair process. However, obtaining all necessary nutrients in a single meal requires careful planning to avoid deficiencies.

Timing Your Single Meal: A Comparison


Aspect	Morning/Early Afternoon (eTRF)	Evening (Later TRF)
Metabolic Health	Generally considered superior due to higher insulin sensitivity and better glucose response earlier in the day.	Insulin sensitivity decreases in the evening, potentially leading to poorer glucose tolerance.
Weight Loss	May be more effective as it increases fat oxidation during fasted periods.	Studies show weight loss is still possible, but potential metabolic benefits may be slightly reduced.
Digestion	Aligns with the body's peak digestive activity. More efficient digestion is common.	Digestion slows down at night, which can cause discomfort or sluggishness for some.
Social Flexibility	Can be challenging to align with family and social dinners, potentially leading to isolation.	Easily fits into modern social routines, allowing for shared meals with family and friends.
Energy Levels	May lead to sustained energy throughout the day by avoiding the mid-day crash associated with lunch.	Can provide a large energy reward at the end of the day, but requires more willpower during the fasting period.

The Role of Consistency

Regardless of the chosen time, consistency is vital for success with OMAD. Eating at a similar time daily helps the body adapt, regulate hunger signals, and manage energy levels, making fasting more manageable.

Who Should Be Cautious?

OMAD is not suitable for everyone. Individuals with diabetes, those who are pregnant or breastfeeding, people with a history of eating disorders, and those prone to nutrient deficiencies should approach OMAD with extreme caution or avoid it entirely, ideally consulting a healthcare professional first.

Conclusion

Determining what is the best time of day to eat one meal is a personal decision based on individual goals, metabolic responses, and lifestyle. Early eating windows may offer metabolic advantages, while evening meals provide greater social flexibility and sustainability for some. Consistency and ensuring the single meal is nutritionally complete are paramount for success with OMAD. It is highly advisable to consult with a healthcare provider before adopting this restrictive eating pattern.

For more information on circadian rhythm and eating, you can refer to the Sleep Foundation's article: What is Circadian Rhythm Fasting? - Sleep Foundation.

Frequently Asked Questions

Yes, eating one meal a day can be unhealthy, especially if not carefully planned. Risks include nutrient deficiencies, low energy, fatigue, and potential for disordered eating. It can also cause undesirable metabolic changes like increased LDL cholesterol and blood pressure for some individuals.

While weight loss can occur with OMAD at any time, research suggests that eating your single meal earlier in the day may offer superior metabolic benefits for weight loss, including better insulin sensitivity and increased fat oxidation.

Some evidence suggests that prolonged periods of fasting could potentially slow down metabolism over time, although research is limited and findings can be mixed. However, proponents of OMAD argue it can boost metabolism through mechanisms like increased fat burning.

Your single meal should be nutritionally dense and balanced. It should include sufficient protein to preserve muscle mass, healthy fats, fiber from plenty of vegetables, and some complex carbohydrates to meet your daily needs in one sitting.

From a metabolic standpoint, some studies indicate that eating earlier in the day aligns better with circadian rhythms and insulin sensitivity. However, an evening meal can be more sustainable for many lifestyles and allows for social dining.

Yes, you can drink calorie-free beverages like black coffee, plain tea, and water during your fasting period. These do not significantly impact the fast. However, adding milk, cream, or sweeteners would break the fast.

The adjustment period for OMAD varies by person but typically takes 2 to 3 weeks. During this time, the body adapts to burning fat for fuel, and hunger signals become more predictable.