All fad diets claim that a certain extremely limited group of foods will help you lose weight really fast. For instance, the cabbage soup diet consists of mostly cabbage, potatoes and bananas. The three-day diet lets you eat grapefruit, a little bit of tuna, a tiny amount of meat or chicken, some veggies, and, strangely enough, a cup of ice cream. The so-called Israeli army diet only lets you eat one kind of food a day - apples one day, cheese the next, and so on.

You really do lose weight on these diets. You have to. These diets used to be called starvation diets for a reason.

But if you go on one of these diets, or any low-calorie diet, for that matter, you want to make sure you don't want to throw away your fat clothes, because within just a few weeks after going off the diet you'll weigh more than you did when you started.

Starvation will cause you to lose weight, there's no question about it. But scientists have known for over 91 years that one of the almost inevitable results of starvation is weight gain. Your body objects strongly to not being given enough food to keep its internal fires burning, and it can't survive for long without the nutrients it needs to keep all the various functions of it's cells working properly.

That's why you slow down when you're on a low-fat diet. You feel tired and irritable because your body is trying to conserve the little amount of food you're feeding it.

You also get cravings for food - almost any food will do, but the cravings are especially strong for the very foods that make us fat - the sugars and breads and pastas and other simple carbohydrates that make us store extra body fat. Since starvation is a threat to your survival, the cravings will continue to get stronger until they're absolutely uncontrollable.

Then you go off the diet, and gain back all the weight you lost. Most people go on to gain an additional 3 to 8 pounds.

And weight gain is obviously not what you had in mind when you started on the diet in the first place.

But the inevitable weight gain is just one of the reasons why fad diets are such a bad idea.

The other reasons are considerably more serious. On the rare occasions when a doctor prescribes a very low calorie diet, of 900 calories a day or less, they almost always require that their patients get constant medical supervision. That's because this qualified as a starvation diet, and they can be very risky.

Even 'normal' reduced calorie diets have health consequences. That scientific study I mentioned earlier put healthy college students on a reduced calorie diet to see how their minds and bodies would react.

The study volunteers actually ate more calories than the kind of diet that almost every doctor tells you to go on when he thinks you're overweight, and they certainly ate way more calories than you get on most fad diets, like the cabbage soup diet and the 3-day diet. The study had the students eat from 1400 to 2100 calories a day.

A later study done in 1945 for the US army found that the symptoms would get worse if you added exercise to the program.

When I found out about this study, it made me downright angry - why haven't we been told that scientists have known for over 91 years that low-calorie and low-fat diets actually cause the following health problems: Listen closely to this list, because this is what you may experience if you go on any of the currently popular weight loss diets:

* Weight gain.

* Depression.

* Food cravings.

* Feeling tired and listless.

* Constant hunger.

* Reduced interest in sex.

* Chronic fatigue.

* Hypothyroidism.

* Hormone imbalance.2100

* Scaly skin or eczema.

* Premature wrinkling of the skin.

* Dandruff or dull, lifeless hair.

* Mood swings.

* Chronic yeast infections.

* Poor immune system - frequent colds or respiratory illnesses.

* Digestive problems.

Most people believe that the only way to lose weight is to cut back on the calories, even though scientists have known for almost a century that those serious psychological and physical problems could result.

Let's take a close look at some of the most serious symptoms on that list:

Depression, mood swings, and chronic fatigue. It is impossible to be motivated to stay on a diet, (or to do anything else, for that matter), when you suffer from chronic depression.

Heck, those healthy college-aged men who participated in the low-calorie diet studies even lost their interest in sex.

And many people take antidepressants, like Wellbutrin, for both depression and to lose weight.

Two important studies have found that the depression caused by a reduced calorie diet may actually get worse for a while after you start eating normally again. It takes time for the body to recover from semi-starvation eating plans.

Constant hunger and food cravings, especially for refined carbs: When you combine the lack of motivation that always accompanies depression and chronic fatigue, and match it up with constant hunger and food cravings, it shouldn't come as much of a surprise to find out that most people who start a low-calorie diet will actually end up gaining weight.

The only safe way to lose weight is to eat a correctly balanced diet that gives your body all the nutrients it needs, every single day. Stop eating the kinds of foods that cause the excess storage of body fat, and eat lots of the foods that help you lose weight faster.