This question is to do with any measurment of what is in food: calories, fat, carbs, protein, vitamins or minerals.
Many people seem to talk about how many grams of carbs they eat or their percentage of fat or type of fat. However few non-processed have a list of nutritional content. Real foods also vary a great deal for example due to breed, enviroment, feed, age, length of storage etc. Every steak, egg, carrot does not have the same nutritional content. Nutritional content of foods listed by the USDA (used by nutritiondata.com and fitday etc) is only an average of the few samples they tested. There is also the human factor. Unless you carefully measure how much butter or coconut oil you add to a meal or how many grams of sweet potato you eat any estimates are probably not very accurate.
Personally I have no real idea about how many grams or percentages or calories of food I eat.
Do you really know the details of what you eat?