can not really be used by individuals to adjust their calorie intake, since the degree of inaccuracy will vary substantially with the type of food in question. Rather, it s best to use the food labels to get an approximation of calorie content, and focus more closely on selecting foods with the best nutrient profile.

https://www.acsh.org/news/2015/04/28/some-food-labels-probably-overestimate-calorie-content