Go right ahead and reach for that slice of white bread, for a researcher from the University of Virginia insists that the theory that eating so-called "bad" carbohydrates will make you fat is all hogwash.

Professor Glenn Gaesser insists that the latest common wisdom on carbohydrates is "just nonsense".

Gaesser came to his conclusion after analysing peer-reviewed, scientific research on carbohydrate consumption, glycemic index and body weight.

He found that not only are diets high in carbohydrates almost universally associated with slimmer bodies, but also that consuming lots of high-glycemic foods is not associated with higher body weights.

"There is no reason to be eating fewer carbs -- they're not the enemy," says Gaesser, a professor of exercise physiology and director of the kinesiology program in the Curry School of Education.

"People who consume high-carb diets tend to be slimmer, and often healthier, than people who consume low-carb diets," he adds.

Carbohydrates are classed as "good" or "bad" on the basis of the glycemic index -- a measure of the quality of the carbohydrate in terms of how much it raises blood sugar.

Foods having a high GI such as white bread and doughnuts are generally thought to be "bad" because they raise blood sugar more than "good" carbs do.

Several popular low-carb diets use glycemic index as a key feature for optimum weight control, but it is not a reliable description of carbohydrate quality.

Gaesser also looked for a clear association between carbohydrate consumption and illnesses, such as type 2 diabetes, heart disease and cancer, but did not find any compelling evidence that avoiding carbohydrates with a high GI would help prevent these.

He also said that though reducing any part of the diet -- carbs or proteins or fats -- will result in modest weight loss in the short term, if calorie consumption is reduced, for long-term weight maintenance, a high-carb, low-fat diet is still the best bet.