It's no secret that processed foods contain disquieting amounts of added sugar. Rates of obesity, diabetes, tooth decay and heart disease - all linked to sugar consumption - are rising, especially in countries like China where packaged foods have made fast inroads.

One recently reported statistic was particularly startling: A cup of pasta sauce from the supermarket shelf typically contains 20 grams of sugar. Didn't the health gurus just tell us we'd live long with the Mediterranean diet?

With Italy's National Day on the horizon in early June, we checked in with a fellow who should know: Eugenio Iraci, chef de cuisine of award-winning restaurant Barolo at The Ritz-Carlton in Beijing.

"Ready-made sauces are still regarded with a sort of shame among the majority of Italians," says Iraci. "Any sauce should be rigorously handmade.

"A successful tomato sauce has the right balance between acidity and sugar," he says, noting that canners add sugar to balance the acid. "The factors that condition this balance varies from the ripeness of the fruit (the tomato is a fruit) to the actual recipe the chef is using."

The most traditional recipe you can find requires simply a "soffritto" of garlic in extra-virgin olive oil to which you add the tomatoes (the term used to describe this preparation in Naples is sciue 'sciue', which means "quickly").

Eugenio Iraci, chef de cuisine, Barolo

But even in such perfect conditions, Iraci concedes, it would not be unusual for a professional Italian full of virtue and honor to add "a pinch" of sugar, he says.

"But a pinch is a pinch!"

Given the amount of preservatives and added sugar in storebought products, he notes: "I can understand this confusion that tomato sauces are sweet."

Meanwhile, the World Health Organization recently sounded a battle cry: Only 5 percent of our total daily calories, it now recommends, should come from sugar.

That works out to about 26 grams of sugar per day in a 2,000-calorie diet - a hefty reduction for many folks, especially those who don't prepare home-cooked meals from fresh ingredients. A can of Campbell's tomato soup contains 26 grams of sugar all by itself, while a cup of store-bought cabbage slaw includes 23 grams.

The WHO's new recommendation, however, has stirred debate, with some experts like US dietitian Keri Gans saying a 5-percent sugar diet "is unrealistic". Gans, author of The Small Change Diet, recently told Time magazine: "We should focus on what we should be eating and not what we shouldn't be."

Chef Iraci notes that the modern lifestyle has left its mark even in Italy.

"The original Mediterranean diet is now contaminated with refined carbohydrates, sugars and processed foods," he laments. "To ensure that sauces and any other dish is healthy, it is always best to prepare it using the freshest, best-quality ingredients you can afford - and to take the time to prepare it yourself."