Don't "diet", simply make small changes to your current diet.
Water is your friend, drink 8 cups daily, and don't drink anything except water until you have met your daily quota. Americans drink 1/3 of the calories they consume in a day, get rid of all soda, tea, sweet coffee's etc.
Don't consume unnatural sweeteners, aspartame etc.
Now, add fresh to your diet. Homemade soups, stews, salads, sandwich's made with fresh veggies.
Eat homemade everything, don't eat out more than once every couple of weeks. When you do eat out, buy from the kid's menu.
Add in an exercise three times a week.
Shop in the fresh foods- avoid canned, boxed, or otherwise prepared foods.
This is the first step to being a slimmer, healthier, happier person.