When people ask for advice on weight loss, those who are more of an emotional disposition and less of a logical/rational one usually tend to get that "food phobia" thing. I'll spend forever trying to offer advice to them on everthing that worked for me. I always warn that what works for one might not work for another, but some things are pretty universal. It's a good idea to avoid starch and sugar since it offers a lot of calories and no satiation. It's a good idea to eat lots of veggies because they're healthy and add bulk to meals. When you want to impulsive eat and snack, instead of just denying yourself (that wont work) make healthy choices. Grab a baby carrot instead of a handful of chips. Learn to listen to your body and determine which hungers are "true" and which are just yearnings to nibble because of boredom. Feed the previous hunger with the right foods that control sugar; feed the latter hunger with big salads made of zero cal dressings and baby carrots .
It's a bad idea to try to be really extreme and not try to enjoy your diet since that will lead to cheating and binging.
It's a good idea, most importantly, to listen to your body and pay attention to how food makes you feel, impulses to eat, what they mean. Think hard on it and really focus and you'll know what you have to do to reach yoru goal.

I find very often the case they'll try this advice for awhile, and they'll feel better and lose weight...but then they'll become dissatisfied with the fact it's taking "so long" to reach goal. They become impatient. Since they view food irrationally (as something that "attacks them and makes them fat"), they view food as an unnecessary hostile alien to their desired shape/body. So then, despite the fact it goes against generally good advice and common sense, they attempt to be really strict to speed things up. They'll cut out meals, they'll go to bed starving. They keep this up for a short period of time and then they eventually break down and give up and start eating poorly again.

It all comes down to not being rational about this, having an irrational emotional approach to weight/size/food produces the extreme thoughts (unrealistic expectations, the belief that food is unnecessary and the less the better, etc), which leads to extreme behaviors, and inability to be moderate.