I'm not sure I know anyone like that. I mean, I know they exist because I've seen them documented. But people I know in real life--I have no idea, skinny or fat, how many calories they burn in activity/exercise per day, or how many calories they eat.
On the other side, I'm sure there are people at work who think I'm leaner than usual for my age because I don't eat much at work, most days just a 60 gram packet of poutine cheese curds that claims to have 200 calories. Not everybody knows that when I'm in maintenance, I go through a half liter of heavy cream a day, that's 1600 calories before adding my protein foods.
Just cutting out dessert--one way to make that effective is to eat way too much dessert to start with.
I'm somebody who can lose weight by cutting out dessert, but my dessert is 800+ calories of homemade heavy cream ice cream.
I don't think counting calories or measuring is useless. But the smaller the deficit you're shooting for, the less likely you are to even have one.
The stereotypical bodybuilder diet--tuna and lean chicken breast, white rice, broccoli.
Or the fish and rice cakes guy;
Limited variety of foods does make it easier to portion out a more precise amount of food. It still might not be as precise as you imagine. But if on paper, one month, you're eating 2500 calories of such foods, and then the next month you eat 2000 calories of such foods--you likely are eating 20 percent less calories or so. If you're eating from restaurant menu boards, and varying your choices, maybe not so much. Lean protein sources--not my favourite, but variation in calories will be less. A fatty pork chop--I don't think I'll know, looking at the fat streaks, that my pork chop has 20 percent fat versus 30. In terms of keto--if you wanted to go the calorie counting route, very lean protein sources and very fat fat sources--butter, lard, heavy cream--is probably more precise than various fatty meats.
Probably on average, even with fatty meats, if you stay to the same cuts at the same store, you'll know you're eating less if you go to say 5 ounce portions of pork chops versus 8 ounce. I measure more for keeping protein from going too high because I target ketosis. There I don't care as much that the numbers aren't quite real because if one meal has 6 grams of protein per ounce of meat and the next 8, it doesn't really make that much difference.