Many studies have been done in order to isolate causes and contributing factors to the scourge of obesity smothering the nation. I am addressing one particular concern: Are you really that hungry?
Every day at work or shopping I see a great problem: people who feel the need to eat the items they are purchasing while they shop. There is no way that all of the people I see eating a gigantic bag of Ruffles and drinking a Yoo-Hoo while pushing a cart-load of junk are stoned. It is also not possible that the 500lb man eating cookies really can't wait to get home to break open the box. Hey, fat boy, what is up with that? I wonder why your blood sugar is raging out of control. Hey you, lady with the ass trying to reverse digest a chair and crying into a plate of donuts with a double espresso latte, maybe this is partially why your toes have gangrene and you feel like crap all day long,
I don't say these things to be cruel. I myself am known to overindulge and be utterly lazy. The difference here is that I am overweight but I can still see and touch my toes. My blood sugar is relatively normal. I do not get frequent infections in weird places. I can run three miles before I need to sit down. I can also shop for food, pay for it, drive it home, put it in its proper kitchen resting place, and sit down to enjoy my chips and beer when said shopping excursion is over and done: not while I am in the process of shopping.
Moral of the story: DON'T EAT IT TILL YOU GET HOME! That way you have at least burned off a few calories between picking up the chips and eating them instead of eating them and going back to get another bag to take home.