July 6/Sydney, Australia/ABC Transcripts -- For years, the diet conscious have been warned to watch out for starch. It is the most common carbohydrate in the human diet, but it is also seen as one of the main culprits behind the burgeoning obesity epidemic.

Now, however, an American researcher is singing the praises of a particular type of starch, some found in potatoes and corn that he says can help us lose weight by making people feel full.

The University of Colorado's Paul MacLean says if breakfast cereal makers incorporated digestion resistant starch into their products, consumers would all be better off.

Most Australians who have tried to lose weight in recent years have probably begun by cutting out much or all of the starch in their diets, but it seems that might not be the best move.

MacLean, associate professor of Medicine at the University of Colorado, says, "Not all starches are evil and particularly not all carbohydrates are evil. Carbohydrates are actually a fundamental part of our diet.

"The types of carbohydrates that should be avoided in really large amounts are the simple sugars. It's not like we can't, you know, eliminate those completely but avoiding them in large amounts and of course we can't completely change over and have a diet completely of resistant starch.

"So, it's shades of grey here."

What Paul MacLean says is the good starch -- resistant starch -- earns its name because it is resistant to digestion.

"This type of starch passes through the small intestine, goes to lower bowel where it has beneficial effects on bowel health. It's beneficial for helping us to control weight."

So what is it that resistant starch does that helps us to regulate our body weight?

"It will help us not feel hungry or it will stave off the next bout of a meal affecting how much food we eat because of its satiating effects. However, my research and what's its pointing to is that the effects that it has on helping our glycaemic levels in the blood, our glycaemic control, can help us sustain lean mass growth and bone health when we're trying to lose weight."

Resistant starch is in potatoes, whole grains, legumes, unripe bananas, and cooked and cooled starchy foods like sushi rice and potato salad, but MacLean says the benefits could be spread around if it is added to other foods.

"You can actually put this starch in and use it as part of the baked food. So you don't necessarily have to have a potato or a, you know, a banana. This is a food constituent that could be used to make up some of the things that we eat every day."

From the July 19, 2010, Prepared Foods E-dition