You do realize that most of the fast food chains that offer salads post the calorie count of their food. The salads typically have more calories than a burger and fries.
Many people who have had coronary bypass surgery are thin people who had a diet low in calories but high in fat and salt, David Letterman comes to mind. Please learn how intakes of calories, fat and salt are actually processed and stored by the body before blaming random shit for causing obesity.
When it comes to how healthy a meal is, you have to take everything into consideration: calories, fat (saturated and trans vs. monounsaturated and polyunsaturated), sodium, sugar, cholesterol, amount of ingredients, how processed something is, etc.
While it's true that proper nutrition is important and what you eat can affect how well your body works, in terms of gaining and losing weight calories are important. With a low calorie intake you can lose weight even if what you're eating is junk food. This was demonstrated by Mark Haub, a professor of human nutrition at Kansas State University.
http://www.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor/
That's not why we have obesity. We have obesity because people are lazy and don't care enough to take care of their health. People can easily afford to eat healthy, just stop eating out and make your food at home and bring it with you if need be, it's way cheaper. And don't waste your money on things you don't need.
Yeah, because nobody should have to pick $9 and healthy over $3 and crap. Nobody should have any responsibility to make the smarter or better choice, only the cheapest choice.
http://www.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor/