The prior post dealt with basic units of nutrition. The key is to develop a diet that matches your desires and your body. Every person has different calorie requirements and metabolism. Calorie needs start around 1200 and up (based on weight and age). There are calorie calculators available on multiple web sites.
Exercise is also very important to maintain weight loss. I have found that my most successful patients incorporate exercise into their routines. Walking vigorously for 45 minutes may only burn 150 calories.