Everything You Need To Know About The OMAD Diet

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You’ve probably heard of people losing weight and experiencing other health benefits through intermittent fasting. Perhaps you’ve even considered trying it. An increasingly popular form of intermittent fasting is the One Meal a Day (OMAD) diet in which you only eat one meal per day. 

We know what you’re thinking—is that healthy? The answer is both “yes” and “no.” Let’s explore OMAD and intermittent fasting to determine if you should incorporate a fasting regimen into your life.

What is intermittent fasting?

Intermittent fasting means eating only during a certain time frame each day. It has been shown to reduce abdominal fat, help maintain muscle mass, and reduce resting heart rate and blood pressure. Intermittent fasting can even launch your body into a state of ketosis where it burns fat, not sugar, for energy. Because fasting lowers your blood glucose levels, ketosis has been shown to mitigate the effects of type 2 diabetes

What is OMAD?

Following an OMAD regiment means fasting for 23 hours and eating for only one hour a day. This 23-hour fasting period is strict; in order for your body to experience maximum effects, you shouldn’t consume a single calorie—not even from beverages (though drinking plenty of water is encouraged). 

Most people following the OMAD plan eat their single meal when their bodies are at a peak metabolic rate and they are the hungriest. This is often in the middle of the day or perhaps early evening. The rule of thumb is to eat your meal immediately after you are most active. 

If you’re thinking OMAD sounds more like starvation than dieting, you’re not wrong. Because OMAD doesn’t require you to make changes to the food you eat (though we still recommend you eat healthily), OMAD isn’t actually a diet—it’s a fasting/eating schedule. When consuming just one meal a day, you’ll naturally consume fewer calories because you simply don’t have as much time to eat.

Is OMAD healthy? It’s complicated.

OMAD has received abundant praise from its practitioners, who often claim it’s the one diet that actually helped them lose weight. However, the effects of OMAD on human health are varied and the body of research to date is relatively small. Here are some of the known pros and cons of following an OMAD regimen:


  • According to an article in the Research Aging Review, “Intermittent fasting increases lifespan and protects various tissues against disease.” 
  • Intermittent fasting has been shown to improve cholesterol levels and decrease inflammation in men, and regulate blood sugar levels in mice.
  • Calorie restriction and intermittent fasting regimens can reverse the impacts of mental aging in mice through a process called autophagy—your body’s natural ability to get rid of old, damaged cells and replace them with new, healthy ones.
  • OMAD can reduce stress. In the first study to measure the weight-loss effectiveness of eating fewer than three meals a day among humans, researchers reported a significant decrease in cortisol concentrations among participants. 
  • OMAD and intermittent fasting don’t require you to actually change your diet, which many people like. Therefore, you don’t have to buy different groceries or spend extensive time meal prepping—although eating healthier foods is always a good idea!


  • It can be hard to get started with an OMAD regimen. Eating only one meal a day seriously increases your hunger in the initial phase, where your body still expects you to follow your existing eating patterns. That being said, research shows that hunger associated with intermittent fasting begins to subside after the first few weeks. 
  • It can be hard to follow OMAD long-term. Friends and family may not understand your choice and you may have to skip meals or a round of drinks you would otherwise share with them. (To mitigate this, you can occasionally give yourself a “cheat” day, as you can on any diet plan.)
  • Eating one meal a day can increase blood pressure and cholesterol concentrations, contributing to one’s risk for cardiovascular disease.

When consuming just one meal a day, you’ll naturally consume fewer calories because you simply don’t have as much time to eat.

  • It’s difficult for most people to consume 2,000 calories in one sitting, therefore the OMAD diet may be dangerous because people aren’t meeting their recommended daily calorie intake. Eating under 1,200 calories a day can weaken your immune system. Additionally, when you only eat one meal a day, it’s difficult to get all of the essential nutrients your body needs.
  • People on an OMAD diet have reported trouble concentrating, feeling weak and/or irritable, feeling hungry, and experiencing constipation.

Ultimately, there isn’t evidence that a strict OMAD diet offers any benefits above more moderate intermittent fasting—and it’s clear the potential risks increase with OMAD. While we’re not writing off intermittent fasting, we can’t endorse an OMAD regimen because it’s so extreme.

Alternatives to OMAD

If you’re still set on trying OMAD after reading this, we recommend starting with a light intermittent fasting regimen first. Here are a few popular approaches to consider:

  • Following the 16/8 approach, you restrict your daily calorie intake to an eight-hour window while fasting for the other 16 hours. 
  • The 5/2 method allows you to eat normally for five days a week while eating only one 500-600 calorie meal on the other two days. It’s recommended that your one-meal days be spaced out by at least one day.
  • A study in the Cureus Journal of Medical Science concludes that alternate day fasting—only eating every other day—may be “an optimal solution” because people can eat normally on their non-fasting days. A popular modified version of alternate day fasting is to eat one 500-600 calorie meal on your “fasting” day.
  • The most moderate option is to simply avoid snacking between meals, keeping your focus on eating a healthy diet and exercising regularly—these are, after all, the most tried and true ways to maintain overall good health.

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