Kind of following up on Tate's comment:
Yes, they include MSG which switches off the body's ability to say "I'm full."
Also partially hydrogenated oil, a type of fat God never intended and is created in a laboratory, thus our bodies don't know how to process it and it causes all kinds of inflammation. (Yes, it's not on the label but there is a FDA loophole that allows them to round down to zero if it is .5 g or less per serving..and let's face it, who only eats one serving?)
artificial colors (especially in the cool ranch ones), including yellow #5 which is made from petroleum. (not kidding - google it!) Also blue and red dyes, which my friends with kids tell me makes their hyperactivity and ADD symptoms worse.
a crap ton of sodium (80% of your RDA in twelve chips...and, come on, who eats only twelve chips?)
and practically no vitamins and minerals or anything else beneficial.
Don't get me wrong, I like the taste, too. But looking at the ingredient label and knowing the impact on my health can help me to steer clear.