You are naive and misinformed. This is wrong with regards to about everything you just said. Basal metabolic rate varies dramatically with the amount of lean m

You are naive and misinformed. This is wrong with regards to about everything you just said. Basal metabolic rate varies dramatically with the amount of lean muscle mass. You can rapidly lose lean muscle mass by having too high of a caloric deficit which is dependent on overall fat %. The less fat, the smaller the deficit. Some people have metabolic disorders, others have allergies or sensitivities which cause inflammation that halt fat loss. This includes inflammation from leaky gut, or certain common gut-based infections that are almost impossible to get rid of like H. Pylori. Physical activity's impact is almost neglible compared against diet and muscle mass. Also a calorie of a food is not necessarily a calorie of the same food cooked differently, the caloric availability changes depending on preparation.