It seems too good to be true.  Eat as much as you want and still lose weight?  That's the conclusion of a group of health experts who say a vegetarian diet is just the ticket for losing those unwanted pounds or kilos.  But others say a side order of common sense goes along with it. 

American staples: hamburger and fries

Hamburgers and french fries ... staples of what's called the "Western diet".  Quick ... easy ... often cheap ... and very fattening.  This calorie-rich diet has become one of America's most successful exports.  McDonald's and other fast food restaurants are popping up in China and elsewhere, and health experts lay much of the blame for a worldwide problem of obesity at their doorsteps. 

Obesity is a serious health problem in the United States.  Fad diets that guarantee weight loss often make headlines.  But one of the latest studies to grab attention supports the old-fashioned notion that if you eat your fruits and vegetables, you can lose weight.

Susan Levin

Washington dietitian Susan Levin is with the Physicians Committee for Responsible Medicine, which conducted the research.  She says the diet is simple: just whole grains, fruits, vegetables and legumes. "Those are the four food groups that a plant-based diet should be built around and those food groups are so high in fiber and typically low in calories and low in fat that you don't have to think about quantity."

Janet Zalman

But Washington nutritionist Janet Zalman is concerned about the reality of sticking to this kind of diet. "I think that's for most busy people in major cities pretty impractical because there's no way you can really eat in any kind of restaurant and do it in an effective way, because everything is going to have some butter, some cheese, and I think only having fruits, vegetables,  grains and some nuts is going to be a plan that you're really going to be hungry."

Susan Levin agrees that even a vegetarian has to watch out for the fat. "You don't want to eat things like a lot of olive oil ... a lot of cheese ... a lot of anything that's high in fat, because that's where you get in trouble."

Butter and cheese are what separate the vegetarians from the vegans, says Gail Naftalin, who runs a vegetarian catering company in Wheaton, Maryland.

Gail Naftalin

As a vegan, she doesn't eat dairy products and finds other sources of calcium in leafy green vegetables, like kale.  Gail believes the nutritional balance in her diet can be found in the colors of what's on her plate. "So that if you even think about it in terms of colors, you know ... 'have I had some green things, some orange things, some yellow things,' you can get your nutrients very well satisfied that way."

With the growing concern about obesity and related problems of heart disease and diabetes, Americans are becoming more particular about what they buy.  Frozen vegetables from the grocery store may be more convenient, but Gail Naftalin says fresh produce from the local farmers' market has more appeal:

"Local ingredients that haven't had to be trucked across the country and seasonal ingredients that are growing now -- and that's the food that people really enjoy the most."

So, what is the food you enjoy the most?  Gail Naftalin believes variety is the spice of healthy eating. "Meat eaters certainly can eat vegetarian food, whereas if you have something with meat or chicken stock, the vegetarians won't eat it.  So it's a nice safe route to go and it's healthy and it's setting a good example."

Setting a good example can be critically important to your health.  A British study of 500,000 people in 10 countries has shown that a high fat diet is second only to tobacco as a leading cause of cancer, and when combined with alcohol, accounts for almost one third of the cancer rate in developed countries.