I would say one of the main reasons is the cost of food...Vegetables and diet food are expensive....Filling food is filled with carbohydrates and there you gain weight...For many eating is a comfort...They look at life around them and get depressed....They eat to fill this freight with comfort of the moment...Now add to this that years ago they came out with the no fat and low fat foods....People brought them like mad...They considered them a free for all as far as eating...Counted fat instead of calories...The only problem is where the fat was missing other things were filled in that added weight...This alone, in my opinion, could have been a big mistake....I diet by counting the calories...I diet constantly....It is part of my life...I love it...But, this is me....These are just my thoughts....Take care...
I would say, A combination of excessive caloric intake, increased reliance on automobiles and a lack of regular physical activity is mainly responsible for the obesity.
The causes are primarily overeating and sedentary lifestyle.