The following principles should be at the core of any weight loss plan. You can forget quick-fix diets, if you follow these rules and maintain your diet you will lose weight.

1. Improve your health - Make sure your diet includes adequate amounts of vitamins and minerals.
Drink plenty of water and get enough sleep and air.

2. Reduce the amount of calories you consume - To lose weight you have to consume less energy than you use. The 2 ways to do this are to exercise more and to eat less, cut down the size of your meals and stop eating large quantities of high-calorie food.

3. Boost your metabolism - You should be careful not to reduce your calorific intake too far as doing this will reduce your metabolism and slow your weight loss, changes should be made slowly to allow your body to adjust. The best way to increase your metabolism is to exercise more.

4. Keep hunger at bay - Hunger will be the main challenge to your successful diet. You should always try to eat before you get hungry as hunger can take a long time to go away.
Eat smaller, more frequent meals, and include more slow to digest foods in your meals, such as protein and fat - but you will need to be careful to keep a balanced mix of carbs/fat/protein in your diet.

5. Keep a food diary - This is a great way to track your intake and prevent yourself from lapsing back into old ways of eating. The best time to make an entry is just after you've eaten - it will make you consider everything you eat. This is also a good place to add up the calories you've eaten every day.
