Why is eating your food quickly bad for you?

No, fast foods are generally not good for people if they live off it. There are three things that make food taste good and that is salt, sugar and fats. The FDA is now on a rampage and forcing many restaurants (some of the big franchises) to clean up their act. Now there are more fast food restaurants where you can have the choice of healthy foods such as salads, homemade soups, etc., or junk food.

Junk food causes obesity in people and isn't heart healthy. However, in the Western countries we are suppose to have freedom of choice so if a person doesn't care enough to eat properly and only have a little junk food (treats every so often) then they pay the price. If we start allowing governments to dictate what we can eat, where one can smoke (even outside) then they will be telling you what you can read, what religious beliefs you can have and that's called Dictatorship.

In general (although there are exceptions), fast food items contain too much salt, fats, carbs, and cholesterol to be considered "healthy" (Or rather, "healthful", as the correct term is.)

A documentary was made, in which an individual ate 3 meals a day at McDonald's for a month. This was done under a doctor's observation. According to the doctor involved and the physical appearance of the individual, his health suffered greatly from the experiment.