Introduction
The One Meal a Day (OMAD) diet, a type of intermittent fasting, is one of the strictest eating plans. You eat one meal of your choice, then fast for the rest of the day.
Supporters say it helps with weight loss, sharper thinking, and even longer life. However, critics say it is hard to follow, risky for nutrition, and may cause harm.
You can read more about why diets often fail and what actually works in practice in the article “Why Diets Fail (And What Actually Worked)” from Everyday Mastery.
So, who is right? And what does the science say?
This guide looks at OMAD’s benefits, problems, and evidence. In addition, it shares what short trials and reports show. Above all, it aims to give you clear, simple facts you can use.
What is the OMAD Diet (One Meal a Day)?
OMAD is a fasting plan where all daily calories are eaten in one meal. This is usually within one hour. As a result, you fast for about 23 hours and eat once.
Unlike diets that cut calories, OMAD is based on timing, not food type. There are no strict food rules you could have a burger meal and a cake if you wish. However, success depends on the quality and balance of the meal.
In short: one plate, once per day — nothing else
Medical News Today – OMAD Diet Explained
Potential Benefits of OMAD
🔹 Weight Loss
Eating once a day often lowers calorie intake. As a result, many people lose weight. For example, a controlled study showed reduced body weight when meals were limited to once per day [Stote et al., 2007].
🔹 Fat Burning & Ketosis
Long fasts push the body to burn stored fat. Furthermore, fasting may trigger ketosis, where ketones fuel the brain and body. Because of this, many people report more steady energy [Patterson & Sears, 2017].
🔹 Better Metabolic Function
Fasting helps the body switch between carbs and fat for energy. In other words, the body becomes more flexible in how it fuels itself [Sutton et al., 2018].
🔹 Cellular Health Benefits
Fasting can trigger autophagy. This is a process where the body clears out damaged cells. It links to longer life, better immune health, and less inflammation [Mizushima & Komatsu, 2017].
🔹 Improved Mood & Energy
Many people report fewer cravings and sharper focus once their body adjusts. In fact, some small studies show fasting can also help mood and brain health [Paoli et al., 2019].
🔹 Improved Insulin Sensitivity
Insulin resistance makes it hard for the body to use insulin well. It is linked with weight gain, type 2 diabetes, and poor metabolic health.
Fasting has been shown to lower insulin levels and improve sensitivity, even without weight loss [Sutton et al., 2018]. OMAD may give similar or stronger effects, although further research is needed. At the same time, lighter fasting plans can also improve insulin control.
🔹 Reduced Disease Risk
Fasting plans are linked with better insulin control and lower inflammation. Therefore, OMAD may lower the risk of obesity, type 2 diabetes, and heart disease [Patterson & Sears, 2017].
What the Science Says
Research on OMAD is still early.
Short-term human trials: A study compared one meal to three meals per day. It showed better fat burning but also more hunger and some muscle loss [Stote et al., 2007].
Population studies: Some link one meal a day with higher risk of heart problems and death [JAMA Network Open, 2022]. On the other hand, other research shows strong benefits when diet quality is high.
Broader fasting research: Intermittent fasting plans like 16:8 show clear benefits for weight and metabolic health. In fact, these lighter versions often work as well as stricter methods like OMAD [Sutton et al., 2018].
Animal studies: Meanwhile, animal research shows fasting can boost brain health, autophagy, and lifespan [Mizushima & Komatsu, 2017].
Who Promotes OMAD?
Dr. Jason Fung – A kidney doctor and author who uses fasting to treat insulin issues and weight gain.
Dr. Eric Berg – A health coach who promotes fasting and OMAD for fat loss and brain health.
Celebrities – Bruce Springsteen and Chris Martin (Coldplay) say OMAD helps them stay slim and in control.
Overall, advocates highlight OMAD’s simplicity and discipline.
Concerns & Criticisms (and How They Can Be Addressed)
⚠️ Nutrient Deficiency
It is hard to get all protein, vitamins, and fiber in one meal.
Solution: Use nutrient-dense foods. Include protein, vegetables, healthy fats, and whole carbs. Nevertheless, this issue can be managed with good planning. In contrast, poor food choices can make OMAD unhealthy.
⚠️ Risk of Disordered Eating
Some fear OMAD may cause binge eating. Yet many users say it reduces cravings and helps them feel in control.
⚠️ Negative Health Outcomes
Some studies link meal skipping with higher death rates [JAMA Network Open, 2022]. However, context matters. Many people in these studies already had poor diets or other risks.
⚠️ Digestive Stress
Eating a very large meal can cause bloating or discomfort.
Solution: Keep portions moderate and meals balanced.
⚠️ Lack of Long-Term Trials
True — OMAD trials in humans are still limited. Although gaps remain, history shows humans often ate one main meal a day when food was scarce.
National Institutes of Health (NIH) – Intermittent Fasting and Human Metabolic Health
What Short-Term Experiences Show
Reports and studies show common stages. For instance, many people report hunger first, then better focus later.
Real 30-Day Results Reported
In a small controlled trial, people eating one meal a day lost between 3–5 pounds in 30 days while also showing better insulin sensitivity [Stote et al., 2007]. Other reports note reduced cravings, improved focus, and better appetite control by the end of the month. While not dramatic, these changes are meaningful for many beginners.
First 1–2 weeks: Hunger and low energy as the body adapts.
Weeks 2–4: Appetite settles, cravings fall, focus improves.
After 30 days: Many see modest weight loss, sharper thinking, and more time for daily life.
Is OMAD Right for You?
OMAD may be effective for:
- Adults who want weight loss
- Busy workers who want simple eating
- People already used to fasting
OMAD may not be good for:
- Children, teens, pregnant or breastfeeding women
- People with diabetes or illness (unless supervised)
- Athletes who need high fuel
Alternative Intermittent Fasting Methods (16:8, 20:4)
Many experts say lighter fasting plans are easier to keep up. For example, the 16:8 plan (16 hours fasting, 8 hours eating) or the 20:4 plan (20 hours fasting, 4 hours eating).
Large studies show these give similar benefits for weight and metabolic health. At the same time, they reduce risks like poor nutrition or stomach upset.
For many, these plans act as a first step to OMAD. In summary, they may be the best option for long-term use.
Tips for Trying OMAD Safely
- Start with lighter fasting (16:8 or 20:4) before OMAD.
- Focus on whole, nutrient-rich foods.
- Drink plenty of water.
- Stop if energy, mood, or performance drop.
Balanced Conclusion: Is OMAD Worth Trying?
The OMAD diet is debated. Many praise its simple style and strong effects. However, others warn it is too strict.
What the evidence shows:
Short-term: Weight loss, fat burning, focus, better insulin sensitivity.
Medium-term: Appetite control and steady energy.
Long-term: Still unclear — ultimately, success depends on food quality and health status.
For some, OMAD is a strong tool for discipline, weight loss, and mindful eating. For others, it may be too hard to follow. Overall, the best plan is the one that matches your lifestyle and health.
The bottom line: OMAD is not magic. But if you eat well and stay flexible, it can be a safe and useful plan. As well, it can help build discipline and awareness around food. Some people get benefits by using this short term to deal with insulin resistance & achieve some weight loss before continuing long term with Intermittent fasting
👉 Thinking about OMAD? Start slowly, listen to your body, and get advice if you have health issues.
👉 Tried OMAD or other fasting plans? Share your story in the comments — and subscribe to Homosapien Health for more simple, science-based health tips.
