Fast weight loss diets are not for the faint of heart. They're not based on balanced eating plans. You shouldn't exert yourself when you're on one because they can put stress on your body. And you should never stay one for more than a week. Most important of all though, BEFORE you launch one of the diets promising fast weight loss, visit your doctor and get medical advice. Here are three of the most popular fast weight loss diets:

The Three Day Diet is the simplest of the three diets. It consists of an exact menu for three days. Each breakfast is one small amount of protein, one starch, and one fruit. On one day you'll have an egg, 1/2 of a banana, a piece of toast, and black coffee.

Lunch is even less. It's a small amount of protein and a starch. For one lunch you're recommended to have 1/2 cup tuna and a piece of toast along with your black coffee. Dinner is a little different. You will have a larger serving of protein, 2 servings of vegetables, a fruit, and a cup of regular vanilla ice cream. I personally think it's also one of the strangest diets.

However, there are more of these diets that also have their quirks. One is the Chicken Soup Diet. This is based on a complex recipe for chicken soup. You get some choices of different breakfasts, and then you eat as much soup as you want the rest of the day. One breakfast for the Chicken Soup Diet might be Total cereal, nonfat milk, and juice. A different one would be yogurt, fruit, and wheat germ. When it comes to diets for fast weight loss, with the exception of breakfast this one has zero variety and is boring.

The Grapefruit Diet is one of the most intricate of the 3 fast weight loss diets. There's a lot to remember, and it's all considered important. For instance, there's a certain amount of grapefruit or other specified juice to eat with each meal. You're warned not to eat more or less than what's suggested. Otherwise, it's said the diet will not work.

Also, you're not allowed to take anything away from the diet. If you don't want to eat two slices of bacon with your breakfast - too bad. They claim you won't burn fat if you don't adhere precisely to the diet, including eating the bacon. Hmmm.

A diet like this is hard to understand.

You're also advised to drink 8 eight-ounce glasses of water every day, but only 1 cup of coffee at a meal. Butter can be used as a condiment, or to fry foods. You're only allowed to eat at meal time; no snacking except the beverage at bedtime. You're given two lists: one of foods you can eat and one of foods you cannot eat. Yet, on this "accelerated" weight loss diet you're encouraged to eat until you're full at any meal. Again I say...hmmm.

You're warned not to eat certain foods at the same time they claim the more you eat (of the "allowed" foods), the more you fat you burn. Breakfast on this diet is grapefruit, 2 eggs, and 2 bacon slices. That's the basic guideline however; they also indicate you can eat as much eggs and bacon as you wish. Is this also confusing to you?

Lunch is grapefruit, salad, and meat. Dinner is grapefruit, meat, and a salad or vegetable. You get a bedtime snack of tomato juice or nonfat milk. Yippee! Let's face it - you'll be hungry regardless which of the diets you try. They're extremely restrictive with very, very little food variety. Speaking for myself, that usually means I'll not only be miserable but my chances of sticking to it - even for a short time - are pretty slim. (Pun intended)

And doing fast weight loss diets like this can get complicated. If you do participate in one, please be careful. They may not be safe. And definitely consult with your doctor.