This is what my husband does. He knows that he rotates between a few different meals, so he figured his calorie count for each meal. For example, he makes and eats a breakfast sandwich of egg and Canadian bacon on a low-calorie English muffin every couple of days. He knows how many calories he is eating with that meal. He keeps a list of the foods he eats most often so he isn't always looking up a calorie count.
He measures portions so his calorie count is accurate. He has a very black and white way of looking at different situations and a strong attention to detail. I see things in shades of gray so when I tried to follow his method, I ended up in tears, frustrated with tracking numbers that told me in black and white that my calorie count was too high. Yes, the method is accurate, but feeling bad about myself often ended in binges that I'd record and then feel worse.
Photo by the author ... no, a meatball sub isn't a common meal
Years ago, I read Judith Beck's book, The Beck Diet Solution, which recommended writing out what you'll eat the next day. If you eat the food (in the quantity that you planned), you put a checkmark next to it. If you don't eat a food, you cross it out; if you eat extra (or something you didn't plan on), you circle that food.
Since I'm an opportunistic eater, relying on leftovers or whatever happens to be available in the refrigerator or cupboard for my meals, I wouldn't give too much thought to what I was going to eat until I was hungry or it was mealtime. I wouldn't make good choices. I found that planning out what I would eat the next day (or the next week) meant that I would buy those foods and have them available. Not only did I not have to think about what I'd eat, I had the foods available, which worked with my 'eat what's there' mentality.
Photo by the author. I made the mozzarella but I didn't grow the tomatoes or basil.
If you find that you don't want to deal with the hassle of writing down what you eat, another option is to simply snap a picture of everything you eat. You get a view of portions and what you are eating. This seems like a good option if you want to tweak your diet, say by adding in more vegetables.
You don't have to keep a video diary, but it is another option. One of the reasons this type of diary may work is that many people also post their pictures so they are held accountable for what they are eating. It's sort of like showing a written log to a diet coach.