On a healthy person, reducing calories will work fine. For a person whose body is pumping full of cortisol, thus pumping also with raised glucose and insulin l

On a healthy person, reducing calories will work fine. For a person whose body is pumping full of cortisol, thus pumping also with raised glucose and insulin levels, gradually cutting calories can results in even higher stress response, lethargy, disrupted sleep patterns, reduce satiety triggers, changed apatite towards fat and sugar, and a bunch of other problems that all contribute to the opposite desired effect of loosing weight. A body in panic mode will do about everything except loosing weight unless it is actually medically starving.