I believe in the idea that changes stick better by starting off slow and a single adjustment at a time. Maybe look at the daily allowances charts and find out if your weakness is in sugars or salts and find a healthier alternative. Also add in a few days a week of devoting 15 minutes of exercise to begin.

What is it about your diet that you don't like? Is it late night snacking? Too much soda? Lack of calories? Too many calories? Emotional eating? Too much sugar? Too many carbs?