Let us use a glass of water for further clarification. Water does not have any calories. When we drink cold water, our bodies have to expend an amount of energy to raise its temperature to the same level as our body. Therefore, the cold water is regarded as a negative calorie food since our body ends up burning some calories when we drink it.

On a side note, anorexics tend to find negative calorie foods attractive to their goals of keeping slim. Unfortunately, a diet consisting mainly of negative calorie foods will result in nutritional deficiencies and eventually starvation. This is because most of the calories expended come from muscle tissue.

A more appropriate method of utilising negative calorie foods is as part of a supervised fasting or detox programme. You can fast for one to three days to clean out your system. One good time is right after Christmas season or after having gorged on a lot of food. Of course, it's advised that you seek medical advice before attempting a detox plan.

If you may be thinking that you want to start a negative calorie fasting or detox programme, you must pay attention to these areas:

1. You shouldn't concentrate on eating only one particular food. Foods, in fact, comprise of substances that although natural, can have adverse effects when taken in large amounts. As an example, consuming huge quantities of the acid contained in grapefruit can do much damage to your stomach lining. And other foods might result in diarrhea. Thus, if you can, consume as many of the various different negative calorie foods as you can.

2. To avoid bloating and getting sick, you shouldn't eat throughout the entire day. Having 4 or up to 5 salad meals at different times of the day should be enough. Then, do not over burden your digestive system and just leave it to rest.

3. Eat slowly and make sure to chew your food very thoroughly. This aids in releasing enzymes, plus, you also end up expending more calories. Also, if the negative calorie foods can also be consumed raw such as carrots, it'll definitely be better than cooking them.

4. Begin your fasting regimen when you're free of any kind of important commitments. This is very important for you to consider because while you are in your fasting or detox period, you might experience irritability, fatigue, and headaches. Also, if those symptoms continue, end your diet and check up with a doctor.

5. After your fasting is over, be sure to return slowly and gradually to your previous eating patterns.

Once you consider all the above points, you can go through this list of 20 negative calorie foods that you may wish to try.

* Apples

* Blueberries

* Broccoli

* Cantaloupes

* Carrot

* Cauliflower

* Celery stalk

* Cranberries

* Cucumbers

* Grapefruit

* Green beans

* Green cabbage

* Lettuce

* Papayas

* Pineapples

* Prunes

* Raspberries

* Spinach

* Strawberries

* Tomatoes

It may be worthwhile to repeat that seeing a doctor prior to using negative calorie foods in your detox or fasting program is highly advisable.