There are countless ways to approach dieting, whether you’re trying to lose weight, improve your health, or both.
You can simply try to manage your caloric intake with the CICO (calories in, calories out) diet. You can control your macronutrient intake with a low-carbohydrate diet like the ketogenic diet and Atkins diet, or you might follow a low-fat diet.
Among many other popular diets and dietary approaches, there’s also intermittent fasting, which involves restricting eating windows and extending the length of a prolonged overnight fast.
Falling under the umbrella of intermittent fasting diets is the OMAD diet, an extreme version of time-restricted eating intermittent fasting that involves eating just one meal a day.
In this article, we will discuss the OMAD diet and the pros and cons of eating one meal a day.
We will cover:
- What Is the OMAD Diet?
- How Does the OMAD Diet Work?
- Benefits of the OMAD Diet
- Drawbacks of the OMAD Diet
- How to Do the OMAD Diet
- What to Eat On the OMAD Diet
- 5 Tips for the OMAD Diet
Let’s jump in!
What Is the OMAD Diet?
The OMAD diet, which stands for the one-meal-per-day diet, is a type of time-restricted eating intermittent fasting that people may choose to follow to promote weight loss and/or improve health.
The OMAD diet involves restricting your entire caloric intake for the day to a single meal without having additional snacks or calories outside of the one meal a day.
How Does the OMAD Diet Work?
Like other intermittent fasting diets, the principle behind the OMAD diet is that severely reducing the window of time that you consume calories in a day naturally restricts the number of calories you can eat in the day.
Weight loss is predominantly a matter of maintaining a caloric deficit, such that you are consuming fewer calories per day than you are burning.
A caloric deficit of 3,500 calories per week is enough to lose about one pound of stored body fat.
For some people, generating a caloric deficit can be difficult to maintain, and they may overeat the number of calories they need in a day by the time the day is over.
Diets like the OMAD diet, and other forms of time-restricted eating intermittent fasting diets, essentially make it much more difficult to overeat or exceed your daily caloric intake because you only have a limited time to consume calories.
These time-bound restraints can make it difficult to eat a surplus of calories because it reduces mindless eating and cuts out grazing throughout the day.
For many people, grazing or late-night eating can be a major source of excess energy intake and resultant weight gain. If these potential sources of overindulgence are essentially taken off the table with the OMAD diet, it can be easier to stick within your calorie limits.
In a nutshell, the principle of the OMAD diet is that only eating one meal a day makes it easier to stay in a caloric deficit.
Benefits of the OMAD Diet
There are several potential benefits of the OMAD diet, including the following:
#1: The OMAD Diet Can Support Weight Loss
As mentioned, the OMAD diet can support weight loss because restricting your eating window to a single meal each day makes it easier to maintain a caloric deficit and control your energy intake.
A randomized crossover study found that individuals following the OMAD diet, eating between 17:00 and 19:00 for 11 days, had a significant decrease in fat and body mass with no negative effects on their physical performance.
This showed promising results to the OMAD diet ability to promote weight loss, however, due to the studies small sample size more research is needed.
#2: The OMAD Diet Can Improve Health
Eating only one meal a day necessitates essentially 23 hours of daily fasting. Fasting itself is associated with numerous health benefits.
Some of the reported health benefits of fasting include the following:
- Reducing visceral or abdominal fat
- Reducing insulin secretion and increasing insulin sensitivity
- Improving cellular health
- Increasing the secretion of human growth hormone (HGH)
- Reducing the risk of various diseases, including cancer and neurodegenerative diseases
Drawbacks of the OMAD Diet
There are potential drawbacks to the OMAD diet, such as the following:
#1: The OMAD Diet Is Hard to Maintain
The primary drawback of the OMAD diet is that it is an extreme version of intermittent fasting; as such, it can be quite physically and mentally difficult for people to maintain.
Many people who try to eat only one meal a day end up feeling too hungry at other points of the day, which means that they break the fast and eat anyway, or they try to push through the hunger and fatigue, and often at the detriment to their physical and mental feelings of well-being.
#2: The OMAD Diet Can Cause Binging
Some people find that the OMAD diet promotes binge eating.
If you are only eating once per day, the weight, or importance, of that meal becomes disproportionately significant.
If you have been awaiting your eating window for 22-23 hours, for some of which you were potentially extremely hungry, once it becomes time to eat, you may embark with an all-or-nothing mindset and gorge on as much food as you can get your hands on.
Although our stomachs have a physical capacity, you might end up making poor food choices that end up derailing your diet plans and weight loss goals.
For example, instead of having a sensible meal with lean proteins, vegetables, and healthy fats, you might grab the nearest sleeve of cookies, fast food burger, or heat up a frozen pizza.
It can become easy to want to reward yourself or get in as many calories as you can quickly to satiate your appetite.
In these cases, the OMAD diet may be less healthy than trying to eat sensibly throughout the day by focusing on nutritious foods that manage hunger levels and prevent binges.
#3: The OMAD Diet Can Increase Hunger
Eating only one meal a day isn’t just hard from a psychological perspective, and feeling increased hunger because you are only eating one meal a day isn’t just a trick your mind is playing on you.
Evidence suggests that compared to eating three meals a day, diets that involve eating only once per day can increase fasting blood sugar levels, decrease your responsiveness to insulin, and increase the levels of ghrelin, the appetite-stimulating hormone.
These metabolic effects all coalesce to increase hunger.
#4: The OMAD Diet Can Cause Blood Sugar Issues
Although some studies suggest that fasting can improve blood sugar regulation, there is also evidence that demonstrates that eating one meal a day can increase the chances of hypoglycemia, or low blood sugar, particularly in people with type 2 diabetes.
Symptoms of low blood sugar can include headaches, fatigue, nausea, shakiness, lightheadedness, difficulty concentrating, irritability, mood swings, sleepiness, and anxiety, among others.
How to Follow the OMAD Diet
There are no specific rules or guidelines about when you need to eat the meal, what you need to eat at the meal, or how many calories you need to eat at the meal.
Those decisions can be made based on personal preferences and weight goals.
For example, some people following the OMAD diet eat a large morning meal—brunch or breakfast—and then fast all day and through the night until the next morning, when they break the fast to have their one meal a day again.
Other people extend the overnight fast until early afternoon, and have their one meal a day in the middle of the day and then begin the fast for the later afternoon, evening, through the night, until mid-day the next day.
Finally, some people who practice the OMAD diet fast throughout the entire day until supper time and have a large meal in the evening, repeating the same pattern the next day.
It should also be noted that some people who follow the OMAD diet don’t necessarily engage in the one-meal-a-day eating pattern every single day of the week.
They may have some days during the week where they eat two, three, or more meals and snacks along the lines of a traditional diet but then eat only one meal a day or multiple days of the week interspersed in between.
The key is finding something that works well for you. If you tend to feel sluggish and have trouble focusing if you have not eaten, you might do best by breaking your fast and having your one meal a day in the morning hours.
On the other hand, if you have experience with intermittent fasting and can’t do well extending the overnight fast well into the following day, you might be best served to eat your one meal a day in the afternoon or evening.
In addition, your eating window can be adjusted to anywhere between one to three hours.
What to Eat On the OMAD Diet
There are no specific rules as to what you can or cannot eat when following the OMAD diet.
With that said, the success of the diet—in terms of not only supporting weight loss and improving health but also helping you stay full enough to maintain a 21-23-hour fast every day— is contingent upon the quality and quantity of food that you are eating for your one meal a day.
From a weight loss perspective, the total caloric intake of the meal needs to be less than your total daily energy expenditure, or daily caloric needs, in order to create the caloric deficit you need to lose weight.
For example, if you want to lose one pound per week, you need to burn 500 to 750 calories a day more than you are eating.
If your total daily energy expenditure (the sum total of the calories burned through your BMR, deliberate exercise, physical activity throughout the day, and digesting food) is 2000 calories, you will need to eat no more than 1250-1500 calories a day on the OMAD diet.
In terms of what to eat, the focus should be on whole, natural, unprocessed foods such as the following: whole grains, lean proteins, vegetables, fruits, nuts, seeds, eggs, low-fat dairy, legumes, and healthy fats.
You should limit and avoid excess sugar, hydrogenated and trans fats, excess salt, alcohol, artificial sweeteners, artificial flavors and colors, and highly-processed foods like refined grains, snack cakes, sugary cereals, lunch meats, processed deli meats, fast food, etc.
5 Tips for the OMAD Diet
The following are a few helpful tips for the OMAD diet:
- Focus on fiber, protein, and healthy fats: These nutrients are more satiating and take longer to digest so that you will stay fuller for longer.
- Drink water with electrolytes: Staying well hydrated will keep hunger at bay, but it’s important to add electrolytes to your water during a prolonged fast. This will help maintain electrolyte balance so that you aren’t lightheaded.
- Play around with the schedule: Experiment with the timing of your daily meal and see what works best for you in terms of when you eat.
- Join an online support group: There are Facebook groups and Reddit communities for people doing the OMAD diet. You can find support and tips from others.
- Listen to your body: The OMAD diet doesn’t work for everyone. See how you feel and consider other forms of intermittent fasting or dietary approaches if you are not feeling good eating one meal a day.
For more information on intermittent fasting, check out our 16/8, 14/10, and 18/6 intermittent fasting guides.
These tips for reducing hunger have never worked for me. Whether it’s eating more protein, fats, staying hydrated, etc., I always still feel hungry. And eating healthy sucks. I’ve lost a lot of weight. My heaviest was about 215. I’ve never been that heavy in my life. Now I’m down to 186 lbs. But the crap I’ve had to eat to get there is nauseating. One meal that comes to mind is a chuck steak filet, a serving of baby potatoes, and two servings of broccoli. It was cooked and prepared as well as you can make it, but thinking about it now makes me gag. It wasn’t satisfying at all. Bland. Boring. And broccoli is disgusting. I had to choke it down. I hate all vegetables unless there’s salad dressing to disguise their awful taste. Even the potatoes weren’t enjoyable which surprised me because I like potatoes (more so when they’re mashed with cream and butter or deep fried in oil).
Calories in, calories out works. I’ve lost a ton of weight consuming only BBQ chicken and beer. Forget that thermic crap about certain macros only burning a certain percentage of calories through digestion. At the end of the day, if you burned more calories than you consumed, you will lose weight. Take some vitamins if you’re worried about nutrients.
Sure, my way isn’t ideal, but the important thing is losing the weight. And I feel fine. You can worry about balancing nutrients later. Unless you have some kind of health condition, it’s not going to kill you. You can argue the importance of developing healthy eating habits and relationships with food from the beginning, but you can just as easily do that later.
These health nuts want you to be perfect. That’s why they downplay any weight loss diet that doesn’t prioritize optimal nutritional consumption. They can’t endorse anything different. Maybe for liability reasons? Maybe they’re afraid of criticism? They have to stick to the script. Humans aren’t built that way. Yes, we’ve come a long way in nutrition science and research and have discovered what kinds of diets and foods are optimal for supreme health. But that doesn’t mean adherence to such diets are realistic. If you can do it, good for you. But you’re an outlier. An exception. Not the rule. People like food that tastes good. That’s just the way it is.
So if you want to lose weight, know that you don’t have to punish yourself by only eating disgusting vegetables or bland, tasteless foods. There’s nothing you can do to make healthy food mimic the taste of the foods you love. There will always be something missing. All the alternatives are terrible. You won’t get used to it. Maintain a calorie deficit eating what you want, get the weight off, and then you can implement more nutritional foods in your diet.
Steak with mashed potatoes and broccoli sounds delicious to be honest, they serve that in 5 star restaurants. Just cook and season them perfectly. I think it has to do with you convincing yourself that it is disgusting and being too used to eating crap foods.
I have been eating 2 meals a day for long and now i have retired I came across Dr Jason Fung’s videos on fasting as I am diabetic controlled with metformin but my BP never get stable with pills & I sufferred the side effects worst. So I quit my BP meds & willing to die not of complications surrendering my life to the giver.
Now I acquired new hope and started OMAD 5 days today. My 2 meals before was just skipping breakfast & eat normally like everybody. I was on and off vegan 90% 10% vegetarian when I ocassionally indulge ice scream cakes. I was also not eating healthy as I eat fast food, chips not fully realizing processed veggies have no nutritional value. High blood sugar high insulin. levels; just me dumb.
The transition was easy. Feel more calm, sleeping better eating between 2-3p. I am still learning more about what to eat right as I don’t count calories. Haven’t have found yet but I already feel the difference in small tidbits. I strongly believe OMAD is very healthy in my inflammatory state osteoarthritis osteoporosis worst DM2 & HTN.