I know a woman with unhealthy eating habits. I do not mean to belittle or deride her when I say she is a simple person. I think she is capable of learning about nutritious foods and eating in moderation, but she will probably never be motivated to find out for herself. She is morbidly obese and has a variety of health problems that are exacerbated if not completely caused by the weight and malnutrition. She once said, in regard to eating habits, "I had only mashed potatoes for dinner." She in fact had a dinner plate heaped full of mashed potatoes. Probably enough for five or six servings.
There are a lot of things regular people in this country don't understand about their diets and portion size is one of them. They are the folks who do not read labels and do not measure anything. They assume that all of a 20-ounce bottle of soda is one serving because they will consume it quite comfortably in a sitting. (Actually, if you didn't know, it's 2 1/2 servings so multiply all those calories and other numbers on the nutrition facts panel by 2 1/2.) They are the people who "super size" their servings when dishing up a homecooked meal. Some no doubt think that the food is better for them than fast-food because of where it was prepared.
While the portion sizes and kinds of food offered at fast-food restaurants are certainly not in line with good nutrition, this recent study written up in the Chicago Tribune shows that it is a lifestyle habit to overeat everywhere, not just under the Golden Arches.
Read about the study here.