Quite often it's really a question of gut flora and lack of knowledge regarding good eating habits.

Also fat cells are endocrinologically active, so they try to compel the person to, well, get fatter.

I've been doing this the hard way lately and there's still much that I don't know, because food and lifestyles used to be different, so my parents only told me what they knew from theirs.

To illustrate just how different, my great-grandmother reportedly disliked food that she described as "rich" - too calorie dense for her taste. By this definition cottage cheese was "rich".