Here's my .02 cents Michele.
When losing weight, you shouldn't be so much concerned about the pounds you lose but rather the amount of fat. I would say a safe goal (where you do not lose as much muscle) is about 1-2 lbs every week. The amount of weight you have put on has been gradual so expect the same when you're losing. If you're losing more weight than 1-2 lbs/week, then you should know you're cutting into lean muscle and water.
In a perfect world, 1 lb of fat is equal to 3500 calories. You can go to nutritiondata.com and find out what your daily caloric needs are. To lose a pound a week, you should consume 500 calories less than what is recommended everyday to maintain your weight (daily caloric needs). If you wanted to lose 2 lbs a week, then you would eat 1000 calories less than what's recommended to maintain your weight (1000 x 7 days a week = 7000 = 2 lbs of fat in a perfect world). If you go much higher than this, you're basically starving your body, which will then slow your metabolism and then weight loss will not be as efficient.
You should eat proportionately to your weight, height and lifestyle. So not only should you watch what you eat, but you should also incorporate some form of exercise to your life. The more you exercise, the more energy you need to give your body (the more food you can eat).
Now I'll tell you what I have done since Jan. 2007 to where I am currently at now. I basically eat a diet that has cut out all processed foods. So nothing but whole foods for me. Basically I won't touch anything that comes out of a box or plastic bag. I eat about 2 ounces of nuts everyday (I love all natural peanut butter. Make sure when looking at the ingredients, it should only list peanuts and salt). I drink about 50 ounces of green tea every day. I take around 2.5 grams of omega 3's everyday (my omega 3 to omega 6 ratio is about 1:2 or 3). I consume dark chocolate with over 70% cocao everyday (about .5 ounce). I do not watch the amount of cholesterol or salt I eat (although I am well aware of the amount, it just doesn't mean anything to me). I try to consume around 100 grams of fats, 180 grams of protein (which is a gram of protein per pound of weight) and around 160 grams of carbs (from which around 40-50 grams is fiber). All of my fats come from either canola or olive oil, nuts, dairy, avocado's and meats. My protein comes from a variety of meats. I try to consume chicken, fish, pork, beef and lamb every week however it seems like it's mostly chicken, fish and beef. My carbs come from vegetables, lentils, beans, fruits and dairy, in which most of it is consumed during the beginning of the day (usually before 3 pm) and around my workouts. At night I usually go with meat and vegetables. I eat around 4-6 times a day. So with all this said, I do not touch breads, flour, sugar etc. Not saying you should follow and completely omit these items but they should definitely be limited. One last thing, since our bodies need fuel when we're sleeping, I consume cottage cheese before going to bed (which is mostly made out of caseinate protein, a slowly digested protein).
I wish I knew how much I weighed before, but I believe it was around 270 lbs as of Jan. 2007. I am currently at 183 lbs and have a body fat % of around 11%. I hope no one feels I am bragging, I just know the feeling of wanting to lose weight. If you have any questions (or anybody for that matter), don't hesitate to ask or email me. Good luck.
Erik