Many swear by the one meal-a-day plan to improve overall health and lose excess weight.  So what is the OMAD diet exactly?

The OMAD diet entails fasting for 23 hours each day and eating whatever you like during the one-hour window.

The idea behind the one meal-a-day plan is simple: you need to limit your calorie consumption throughout the day and you can feast on one meal within the one-hour window.

Tea, unsweetened coffee, and water are allowed.

However, other than those, the kitchen is closed—for 23 hours at least.

The OMAD Diet Plan vs. Intermittent Fasting

The one-meal-a-day diet is considered a type of time-restricted intermittent fasting where dieters will fast for 12 hours (or more) each day.

Most people begin their OMAD fasting journey by starting a fast at night, skipping breakfast, and having their first meal in the middle of the day.

For many, eating once a day is so extreme that it makes the other versions of fasting look easy. 

For example, with the 16:8 diet (16 hours of fasting and 8 hours of feasting), most will eat between 9 a.m. and 5 p.m. and fast for the next 16 hours.

Alternate-day fasting (more popularly known as the 5:2 diet) will require limiting your calorie intake for a couple of days each week and eating regular meals on the days between.

How OMAD Works

There are various ways to implement the one-meal-a-day diet.

The purpose is to create a calorie deficit that can result in weight loss.

The OMAD diet offers many health benefits related to fasting including the potential to reduce the risk of developing heart disease, reducing inflammation, and decreasing blood sugar. 

Some popular diets also encourage eating only once a day.

For instance, the Warrior Diet encourages eating only a single meal and cycling between long periods of fasting and short periods of energy consumption.

Can OMAD Help You Lose Weight?

When you are eating only one meal a day, you will consume significantly fewer calories than normal.

Reduced calorie consumption typically results in weight loss. 

A study in healthy adults found that restricting calorie intake to 4 hours resulted in significant body fat loss.

Some research also indicated that intermittent fasting, including OMAD, will often result in weight loss.

An analysis revealed that those who consumed only 1 to 2 meals per day noticed a yearly reduction in their body mass index (BMI) compared to those who consumed 3 full meals per day.

Another study also indicated that fasting overnight for 18 hours or more was associated with decreased body weight compared to those who observed shorter fasting windows.

However, many people can also feel deprived when practicing OMAD.

This can cause binging and eventually, falling off the wagon.

Prolonged periods of restriction will also often lead to yo-yo dieting and changes in the metabolism and the hunger hormones.

The Benefits of the OMAD Diet

One great benefit of the OMAD diet is it can help you get to bed early, a crucial component of any successful weight loss plan.

Getting at least seven hours of uninterrupted and quality sleep each night has been associated with weight management, improved metabolic benefits, and reduced risk of chronic disease.

In addition to weight loss, research also linked OMAD (and fasting) to other health benefits.

Fasting has been known to help reduce LDL (or bad cholesterol) and blood sugar.

Fasting has also been known to help reduce inflammation markers, including C-reactive proteins. 

Moreover, fasting may also boost the health of the nervous system.

According to animal research, it can slow down neurodegeneration and promote longevity.

The Downsides of OMAD

While some research has associated calorie restriction and fasting with many health benefits, some research suggests that too much restriction might do more harm than good.

Case in point: some studies suggest that increased food restriction may result in higher blood pressure levels than normal or less extreme eating methods or patterns.

Other studies have also shown that OMAD can increase fasting blood sugar levels, increase levels of ghrelin (the appetite-stimulating hormone), and delay the body’s response to insulin.

Restricting calories might also increase the chances of low blood sugar or hypoglycemia, especially for those with type 2 diabetes.

Aside from the potential adverse effects mentioned, eating only one meal a day might lead to other symptoms including:

• Constipation
• Irritability
• Low energy
• Dizziness
• Nausea

The OMAD diet is also not recommended for some people, including children and teens, older adults, pregnant or breastfeeding, and those with eating disorders.

Limiting food intake to only once a day may also result in disordered eating tendencies and impact your social life.

Another concern is that it might be difficult to take in sufficient nutrients when you only have one meal each day.

This might result in nutrient deficiencies and impact your health negatively.

In addition, there is also the tendency to binge on calorie-dense and highly processed foods like doughnuts, ice cream, pizza, and other fast and junk foods.

What to Eat and Avoid

Regardless of the type of dietary pattern you prefer, it is recommended that your intake should consist of nutrient-dense and whole foods.

While most health professionals would not recommend eating only once a day, if you want to give OMAD a try, you must consume a variety of nutritious foods such as:

• Fruits. This includes citrus fruits, berries, and bananas.
• Vegetables. This includes broccoli, asparagus, peppers, kale, and cauliflowers.
• Starchy grains and vegetables. This includes sweet potatoes, quinoa, barley, oats, and squash.
• Healthy fats. This includes olive oil, unsweetened coconut, and avocados.
• Legumes. This includes chickpeas, lentils, peas, and black beans.
• Nuts, seeds, and nut butter. This includes macadamia nuts, almonds, pumpkin seeds, and cashews.
• Dairy and plant-based products. This includes cashew milk, coconut milk, and unsweetened yogurt.
• Protein sources. This includes eggs, fish, tofu, and chicken.

In a day the general minimum is eating 1,200 calories each day. 

However, some adults might need more to maintain their weight.

Overall, cramming all the calories needed in one meal is not ideal regardless of your health goal. 

This type of dietary pattern is also not practical or sustainable for most.

It is also ideal to limit the intake of highly processed foods such as:

• White bread
• Sugary cereals
• Chips
• Soda
• Fast food

The foods above offer very little nutritional value and eating them often might lead to increased disease risk and weight gain.

If you want to try OMAD, it would be best to check with your trusted healthcare provider so you will be guided accordingly. 

Conclusion

Eating one meal a day may be a popular way to lose excess weight but it’s not for everyone. While prolonged fasting can offer many health benefits, those benefits can still be achieved using other sustainable methods like 16/8 intermittent fasting. 

You can also follow a lower-calorie diet to lose weight and eat in surplus. Many experts won’t recommend OMAD due to its extreme nature. For most experts, achieving weight loss goals and improving overall health through sustainable methods would be best.