Nutrition Plan

I'm about 6 foot, 180 lbs, maybe 15-20% body fat, and I've packed on a couple of lbs in the past year or so. I work out 2-3 times a week, usually upper body stuff. Ideally I would like to be about 170 and keep the strength I've gained in the past 6 months or so. I'm thinking about doing a week long, hardcore cutting diet. My thoughts are, I do 2-3 protein shakes per day, and fill in the rest with high fiber fruits and vegetables, and 2 or 3 servings of dairy a day, I could cut 5 pounds this week, take a week or two back to normal, then do one more week of the hardcore diet. Does this sound like a completely stupid idea? Or could I actually cut some of my fat doing this...