It's no mystery that weight-loss industry has built a thriving empire. In America, for example, we spend about 35 billion dollars every year on an assortment of weight loss products and plans. In addition, we spend another 79 billion dollars for medication, hospitalization, and doctors to treat obesity-related problems. Even with this, obesity epidemic continues to spread. Sadly, we have become heaviest generation in our Nation's history.

The National Center for Health Statistics reports that we have some very good reasons to be concerned about our weight-gain. Americans, for example are packing-on pounds faster than ever before and weight-related medical problems are taking center stage. Diseases like heart disease, diabetes and yes...even certain forms of cancer have all been linked to obesity.

Here are a few of surprising statistics about our weight:

- A whopping 64 percent of U.S. adults are either overweight or obese. That's up approximately 8 percent from overweight estimates obtained in a 1988 report.

- The percent of children who are overweight is also continuing to increase. Among children and teens ages 6-19, 15 percent or almost 9 million are overweight. That's triple what rate was in 1980!

- Nearly one-third of all adults are now classified as obese. At present, 31 percent of adults 20 years of age and over or nearly 59 million people have a body mass index (BMI) of 30 or greater, compared with 23 percent in 1994.

(The BMI is a number that shows body weight adjusted for height. For adults, a BMI of 18.5 - 24.9 is considered normal. A BMI of 25.0 - 29.9 is overweight and 30.0 or above, is considered obese.)

Modern life both at home and at work has come to revolve around moving from one "seated" position to another: whether it's television, computers, remote controls, or automobiles, we seem to be broadening scope of our inactive endeavors.

At times, life seems to have gotten almost too easy! For entertainment, we can now just sit-down, dial-up our favorite TV program or DVD movie and enjoy hours of uninterrupted entertainment...

And all those simple calorie burning activities that were once a normal part of our daily routine not so long ago? Long gone! You know ones I'm talking about...activities like climbing stairs instead of using escalators and elevators. Or, pushing a lawn mower instead of riding around on a garden tractor. And what about that daily walk to school? Now, our kids complain when school bus happens to be a few minutes late getting to bus stop!

Whether it's Atkins, South Beach or some other low-carb plan, up to 30 million Americans are following a low-carb diet.

Advocates contend that high amount of carbohydrates in our diet has led to increasing problems with obesity, diabetes, and other health problems. Critics, on other hand, attribute obesity and related health problems to over-consumption of calories from any source, and lack of physical activity. Critics also express concern that lack of grains, fruits, and vegetables in low-carbohydrate diets may lead to deficiencies of some key nutrients, including fiber, vitamin C, folic acid, and several minerals.

Any diet, weather low or high in carbohydrate, can produce significant weight loss during initial stages of diet. But remember, key to successful dieting is in being able to lose weight permanently. Put another way, what does scale show a year after going off diet?

Let's see if we can debunk some of mystery about low-carb diets. Below, is a listing of some relevant points taken from recent studies and scientific literature. Please note there may be insufficient information available to answer all questions.

- Differences Between Low-Carb Diets

There are many popular diets designed to lower carbohydrate consumption. Reducing total carbohydrate in diet means that protein and fat will represent a proportionately greater amount of total caloric intake.

Atkins and Protein Power diets restrict carbohydrate to a point where body becomes ketogenic. Other low-carb diets like Zone and Life Without Bread are less restrictive. Some, like Sugar Busters claim to eliminate only sugars and foods that elevate blood sugar levels excessively.

- What We Know about Low-Carb Diets

Almost all of studies to date have been small with a wide variety of research objectives. Carbohydrate, caloric intake, diet duration and participant characteristics varied greatly. Most of studies to date have two things in common: None of studies had participants with a mean age over 53 and none of controlled studies lasted longer than 90 days.

Information on older adults and long-term results are scarce. Many diet studies fail to monitor amount of exercise, and therefore caloric expenditure, while participants are dieting. This helps to explain discrepancies between studies.

The weight loss on low-carb diets seems to be a function of caloric restriction and diet duration, and not with reduced carbohydrate intake. This finding suggests that if you want to lose weight, you should eat fewer calories and do so over a long time period.