> I pity the smoker more because they don’t have to smoke but feel compelled to smoke through addiction.

We all feel compelled to eat.

A lot of cheap food does not satisfy hunger for as long as better food.

Just cutting calories in can make you feel less able to do things, so you automatically cut back on exercise.

People differ in many ways: metabolism, genetics, physical sicknesses, mental health, gut bacteria and probably many more things I cannot think of will change how the same diet affects different people, and their ability to exercise.