I use an app called Carbmanager to track my food intake; but I don’t do it because of OMAD, I do that because of eating a low carb diet. I have found that since I also started intermittant fasting, and usually doing one meal a day, I can be more lenient on what kinds of carbs I allow, and have added a little more fruit back into my diet. I think that because of the one meal, and then fasting, it burns up the sugar and puts me back into fat-burning mode better than if I were eating 3 meals a day, even when they are low carb.
What I do try to do , is to eat healthy, natural foods, so that I get the nutrients from what I eat. I will still have treats with my meal on occasion, but just not very often, so that it does not get to be a habit.
I know that some people do fine with just having the one meal, and eat whatever they want for that meal, and still lose weight; but for me, it works better when I manage my carb intake.