One man put the ‘One Meal a Day’ diet, also known as OMAD, to the test and shared his true thoughts in a video, which may surprise you. The OMAD diet is a form of intermittent fasting which forces the body to burn fat. The person following the diet eats all their daily calories in one main meal, usually within a 1-hour eating window. This is followed by fasting for the remaining 24 hours of the day.