Your second paragraph is the answer to the first. The issue isn't nutritional balance - a good multivitamin pill costs ten cents per day if that's what you're w

Your second paragraph is the answer to the first. The issue isn't nutritional balance - a good multivitamin pill costs ten cents per day if that's what you're worried about. The issue is that fast food is designed to exploit security flaws in your motivation system. That's one of the reasons Americans in particular are suffering so badly from the obesity epidemic despite food being available in effectively unlimited quantity in every developed country. Doubtless given another few thousand years, evolution would patch some of the security flaws, but that doesn't do you any good right now. All you can do as an individual to protect yourself is stay away from fast food.