OMAD diet stands for One Meal A Day Diet. It is a kind of intermittent fasting where you fast for 23 hours and eat in 1 hour. In that 1 hour, you can eat whatever you want. It doesn't limit the amount of calories and the quantity of the food, as long as you consume it within one hour. You may have seen someone do an OMAD diet. But is OMAD a good health practice or just another fad diet?

Reasons for the OMAD diet

Many try the OMAD diet for weight loss or weight management. A 2017 study from a large Adventist population in the US and Canada shows that eating 1-2 meals per day can help Body Mass Index (BMI) reduction over the year compared to those who eat 3 meals per day or more.(1) The study recorded there are only 847 people  that eat 1 meal a day from about 50.000 people. But what happens if someone who usually eats 3 times a day and then switches to an OMAD diet? 


A study tried to compare 1 meal/day eaten in the evening vs 3 meals/day for 8 weeks on each diet on "healthy 4050-year-old men and women with body mass indexes between 18 and 25 kg/m2 with a usual eating pattern of three-meals-per-day." (2)

They experience poorer glucose tolerance and "more prolonged elevation of plasma glucose concentrations," "a significant reduction of fat mass, and significant increases in levels of total and LDL and HDL cholesterol."

The Positive and The Down Side of OMAD

Some might like the idea of OMAD because of spending less time cooking or preparing food, eating whatever you want as long as it is in the 1-hour mealtime, and simply because you don't have to think about many recipes. However, we've seen some problems that might come up with the OMAD diet from blood work. 

What about from a nutrition point of view? It needs to be monitored carefully, whether you get all the nutrients your body needs by eating one meal a day, from carbs, protein, fats, minerals, vitamins, and even fiber. But imagine how much food you need to eat to get all the nutrients your body needs in a meal? 


If you are vegan, plant foods have a lot of fiber, and it makes you feel fuller faster; you might eat low calories and not get enough nutrients. Another concern is that you might experience bloating, indigestion, and an upset stomach by eating too much in one meal.

Eating should give us energy, help us to feel great and not terrible. If eating one meal makes your life worse than better, you might want to reconsider and seek professional's help.