Intermittent fasting is a popular health and fitness fad, and many people utilize it to lose weight. There are numerous varieties of intermittent fasting practices, including one meal a day (OMAD). OMAD is often referred to as 23:1 intermittent fasting. It is commonly used to lose body fat. This diet plan requires you to eat only one meal every day. For the remainder of the day, you should avoid calorie-containing foods and beverages. This eating pattern has both advantages and disadvantages.
What is the One Meal a Day (OMAD) Diet?
The One Meal a Day Diet is a form of fasting. Fasting is defined as refraining from eating and drinking calorie-containing beverages for an extended period of time.
There are two primary types of intermittent fasting diets: time restricted eating (TRF) and alternate day fasting (ADF). Examples include fasting for 16 hours followed by an eight-hour eating session, as well as fasting on alternating days. Intermittent fasting diets all have one thing in common: they require periodic interruptions from eating.
According to L.J. Amaral, a registered clinical and research dietitian at Cedars-Sinai in Los Angeles who specializes in cancer nutrition research as well as ketogenic and fasting-mimicking diets, OMAD involves eating only one meal throughout the day.
How does the OMAD Diet Work?
According to Amaral, the OMAD diet’s one meal is often taken around dinnertime.
“You fast all day for up to 22 to 23 hours,” explains Ella Davar, a licensed nutritionist and health counselor located in NYC. However, non-calorie beverages like water and coffee are permitted throughout the day, she says.
“There are not necessarily calorie restrictions, but most people try to fit all of their [nutritional] needs in this one meal,” Amaral tells me.
“Intermittent fasting has been shown to help individuals lose weight,” says Joan Salge Blake, EdD, a nutrition professor at Boston University and host of the nutrition and health podcast SpotOn!. “However, OMAD is the extreme variant. Weight loss is expected if calories are reduced,” she says, emphasizing how difficult it is to meet all of your calorie and nutrient requirements in one meal.
The OMAD diet has no eating limits or restrictions. As a result, Dr. Salge Blake states, “The meal can contain any food, which can make it unhealthy.” For example, she says that a person “could feast on cookies and cakes” in one meal, making it sugar-rich.
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Many people adopt OMAD, or one meal a day, to lose weight and improve their health. While the mix and timing of meals vary according to personal desire, people on the OMAD diet frequently limit calories to a single meal or a short period of time.
A diet consisting of one meal every day
There are numerous intermittent fasting practices and methods for carrying out OMAD. Examples include eating only one meal per day and fasting during the day, or eating one meal and only a small amount of food during the fast. This type of diet causes a calorie deficit, which can result in weight loss. Other health benefits of fasting include the capacity to lower heart disease risk factors, blood sugar levels, and inflammation.
However, when compared to other fasting regimens, such as the 16/8 method, which takes only one meal per day, it is one of the most stringent intermittent fasting methods.
Some popular diets propose only one meal each day. For example, when following the Warrior Diet, a person eats only one meal per day, alternately fasting and consuming energy.
People who follow the OMAD once-a-day diet typically eat only dinner, while some have breakfast or lunch. Some versions of the one-meal-a-day concept allow for one or two snacks in addition to the main meal. Some OMAD devotees, however, do not consume any calories while fasting and only consume calories during their selected meal.
Implement a weight-loss regime.
To lose weight, you must establish an energy deficit by either burning more calories or eating fewer calories.
The OMAD technique has the potential to help you lose weight because it absorbs less calories than a typical diet. For example, a study in healthy adults found that limiting calorie intake to a 4-hour period in the evening resulted in much higher body fat loss than eating three separate evening meals.
However, this strategy does not appear to be any more effective than typical calorie restriction methods, such as limiting the number of calories ingested at each meal. An research of 50,660 adults using this method discovered that those who ate 1 or 2 meals per day had a lower annual body mass index (BMI) than those who ate three meals per day. Research has also indicated that overnight fasting for 18 hours or more leads to weight loss when compared to shorter fasting durations.
However, the weight loss benefits of this method are associated with fasting. Furthermore, extreme fasting regimens, such as OMAD, might cause adverse effects that people must consider, such as increased hunger and problematic metabolic alterations.
Who should avoid trying the OMAD Diet?
While Dr. Salge Blake recognizes the overall benefits of less restricted intermittent fasting, she does not advocate the OMAD diet to anybody. “There are other ways to improve [health markers] and lose weight without such severe restriction,” she says, adding that she prefers meal timing. “Eating more calories during the day and tapering them as the day progresses can influence your weight and other [health] markers,” Dr. Salge Blake adds, citing a 2013 Obesity Society randomized study[4]. A recent Nutrients analysis from 2021 illustrates the effects of meal timing[5].
Dr. Salge Blake advises against intermittent fasting diets for the following individuals.
- Growing persons, such as children and teenagers
- Individuals who are pregnant or breastfeeding
- Older adults.
- Individuals with a history of disordered eating
- People with diabetes
- Fasting has the potential to influence blood sugar and blood pressure, hence Amaral does not recommend intermittent fasting for anyone using the following drugs without medical supervision.
- High dosages of insulin
- Medications that reduce blood sugar
- Steroid medications.
- Blood pressure-lowering medications
- The OMAD diet, like other intermittent fasting diets, may promote weight loss. However, because it only allows for one meal a day, meeting nutritional needs can be difficult and may have negative health consequences. It can also be difficult for people who love the social components of food, such as family meals and lunch with coworkers, says Amaral.
Less stringent forms of intermittent fasting with a longer eating period that allows for more than one meal or meal scheduling might be more practical than the OMAD diet. Consult your doctor before beginning any new diet. According to Dr. Salge Blake, a licensed dietitian can also provide specialized nutrition advice.
OMAD Diet Food List
Although you can eat whatever you want on the OMAD diet, a well-balanced meal with healthy carbs, lean proteins, and healthy fats will keep you satisfied and energized. Furthermore, “limiting alcohol and added sugar may reduce cravings during the time you are supposed to fast,” states Andrews. She also mentions that you can drink black coffee, unsweetened tea, seltzer water, and other non-caloric beverages when fasting.
During the “eating” part of the OMAD diet, create a balanced plate with
- Fruits, vegetables, and whole grains are all examples of healthy carbohydrates.
- Lean proteins include poultry, eggs, fish, beans, soy products, lentils, and dairy.
- Nuts, seeds, avocado, and oils are all sources of healthy fats.
Is The OMAD Diet Safe?
Before jumping into the OMAD diet, think about the benefits and drawbacks. There has been some studies on the benefits of fasting, but eating once a day is extreme and certainly unsustainable (and potentially dangerous) for most people.
One meal every day: Understand the advantages and disadvantages
The OMAD diet promotes weight loss by challenging your body to burn fat. This diet plan prohibits you from eating for 23 hours each day and requires you to consume all of your calories in one meal. The majority of people simply choose dinner, while others choose for breakfast or lunch. Aside from the one main meal, you are permitted to have one or two snacks in between.
The advantages of the OMAD diet
- It can help you lose weight quickly.
- Unlike other diet regimens, there is no need to calculate calories throughout the day.
- Your one meal can include any food.
- It can assist enhance the metabolism.
The disadvantages of following the OMAD diet
- Studies have revealed that it may increase cholesterol and blood pressure.
- You can feel incredibly hungry most of the time.
- You may also have nausea, dizziness, poor energy, constipation, and irritability.
- OMAD diet can cause nutritional deficits.
- You won’t be able to ingest enough calories at one dinner.
- You will experience decrease of muscle mass.
- It may be tough to sustain.
- It may also trigger blood sugar falls.
Eating one meal a day may help you lose weight, but it can have a negative impact on your health. In addition, it is not a long-term weight loss strategy. A well-balanced, nutritionally dense diet combined with frequent physical activity is crucial for healthy and long-term weight loss.
Risks of the OMAD Diet
While experts agree that intermittent fasting has benefits, they also emphasize the hazards of the OMAD diet and fasting in general.
The OMAD diet’s harsh restrictions “may lead to disordered eating and make it extremely difficult to meet daily nutrient needs for vitamins, minerals, and fiber,” warns Dr. Salge Blake.
“Fasting for more than 14 hours may cause some people to experience a higher stress response, irritability and lower blood sugar,” according to Davar.
“Symptoms of low blood sugar include dizziness, headaches, shakiness, elevated heart rate, and cold intolerance,” notes Amaral, who also warns that the OMAD diet may cause dehydration.
Additional dangers include
Faster weight loss than experts consider safe.
Insufficient calories (less than 1,200 calories).
The OMAD diet does not promote good eating habits.
The diet is tough to maintain, especially in social circumstances.
One meal a day is contraindicated in those with diabetes or who are on certain drugs that have to be taken with food during the day.
Who Can Benefit from Trying the OMAD Diet?
According to Amaral, intermittent fasting can benefit those with metabolic syndrome, borderline diabetes, and those seeking to reduce weight.
Davar suggests that for the OMAD diet, “it may be beneficial to incorporate for one to two days a week, to see if it’s something that your body responds well to.” It may also be beneficial for busy persons with demanding schedules or those who have already tried intermittent fasting and seen the benefits, she adds. She does, however, advocate that you start with less rigorous kinds of intermittent fasting, such as fasting for 14 to 16 hours and eating two to three meals. Always consult with a qualified nutritionist or a medical practitioner before beginning such a diet.
Time-restricted fasting with a longer meal window, such as 8 hours, has been extensively researched. A 2020 review in The Journal of Physiology looked at the effects of time-restricted fasting on weight and cardiometabolic health. They discovered that time-restricted fasting can reduce calorie intake by 20% to 30% while causing weight reduction of 1% to 4% of body weight. Furthermore, independent of weight loss, fasting for a set amount of time reduced systolic and diastolic blood pressure.
Furthermore, having one meal per day may not be feasible if you enjoy exercising, dining out, or traveling. Finally, eating only a few items per day may put you at risk for nutrient deficiencies because different foods contain different nutrients, making it difficult to achieve all of your nutritional needs in a single meal.
Should you try the OMAD diet?
“​​As a registered dietitian, this seems like a punitive eating plan,” Andrews adds. “Personally, I couldn’t do it or advise this to my clients,” according to her. If a person decides to try it, they should drink enough of water to stay hydrated and take a daily high-potency multivitamin to help bridge nutritional gaps. This eating style is not recommended for pregnant or breastfeeding women, those with diabetes, or anyone who has had an eating disorder or is at risk of developing one.
The Bottom Line
Although many types of fasting have metabolic and cardiovascular benefits, the OMAD diet has not been well explored. It’s an extremely restrictive eating style that isn’t sustainable in the long run and can lead to disordered eating practices. However, some people may find it intriguing owing to its simple principles and the lack of calorie limitations. If you decide to try the OMAD diet, please contact with a health care provider.
