I think you missed the point... A 2 liter soda might be $1, but the healthy alternative is free... If a person doesn't care to drink water all the time, you can buy a gallon of unsweetened or sweetened tea for less money. Fruit juice is pricey...but it is also not smart to drink too much fruit juice.
A lot of the statistics for people eating fast food all the time usually cover those that are not only poor, but uneducated to a certain extent. You college kids are different. You're smart enough, but really too heavily on conveniences. If course it's difficult to buy food when so many college kids blow their money on alcohol.