When Samantha Kuczynski contemplated the biggest dietary problem in her lunch recently, she didn't point to the chicken wrap sandwich or the french fries.
It was the dollop of ketchup that caught the eye of the 24-year-old Center Stage props artisan, who was eating outside recently.
The World Health Organization has identified "hidden" sugars in processed foods as a major threat to people's weight and teeth — the condiment contains about a teaspoon of sugar in every tablespoon — and the agency proposed earlier this month that people limit the sweetener to just six teaspoons daily.
Doctors, dentists and nutritionists hope this latest message adds to the information consumers use to make dietary decisions. And they hope it influences public policy and the manufacturers responsible for food content, just as previous campaigns against salt and trans fats did.
"The obesity, particularly child obesity, epidemic can only benefit from such a recommendation," said Kelly O'Connor, a dietitian at Mercy Medical Center in Baltimore.
"There is no research suggesting sugar intake is beneficial in any way, other than it tastes good and often improves our moods," she said. "However, it's become a mainstay of our diet, and for many individuals, it is the foundation of their diet. That way of eating is a recipe for increased risk of diabetes, heart disease, cancer, obesity and numerous other detrimental health conditions."
The World Health Organization's proposal, which recommends cutting sugar from 10 percent of total calories to 5 percent, comes as the U.S. Food and Drug Administration proposes changing the labels on food packages to include added sugars.
Officials say the efforts could help reduce obesity, affecting a third of Americans, and dental cavities, among the most prevalent diseases in children.
That is, if consumers don't tune out the barrage of information.
Kuczynski said she doesn't look at government recommendations but tries to make much of her own food to better control chemicals, salt, sugar and other additives that are "obviously bad for you." But she and a colleague, Elizabeth Chapman, believe such guidelines eventually could influence what ends up on store shelves and, therefore, what the public consumes.
"You have to take some personal responsibility, but you are also limited by your resources and what's available in your area," said Chapman, a Center Stage props fellow. "The amount of sugar in foods is totally unnecessary in a lot of cases."
The World Health Organization agrees. Many countries have adopted the last recommendation made in 2002 to limit sugar to 10 percent of calories, and that's still recommended. But officials say 5 percent is a better goal — the equivalent of about 25 grams of sugar or about six teaspoons for an adult of normal weight.
The new target applies to all "free" sugars added by manufacturers or cooks, including juices and honey, but not sugar found in whole fruit or vegetables.
The recommendation is based on dozens of studies of sugar's effect on body weight. For example, one study found that children who drank the most sugar-sweetened beverages were most likely to be overweight or obese. The agency noted that one can of cola has more than twice the daily recommendation of sugar, at about 15 teaspoons.
In all, the average Americans consumes about 23 teaspoons of added sugar a day, according to the American Heart Association.
World Health Organization officials hope to influence manufacturers, public policy makers and even lawmakers, said Dr. Francesco Branca, its director of nutrition for health and development at the time the recommendations were made. Already, he said, the Philippines, France and some U.S. states are considering forms of sugar taxes, and Mexico recently began taxing soft drinks.
In the United States, the FDA has proposed food label changes that would include a line for added sugars. When a line for trans fats was added in 2006, manufacturers cut back, according to the Center for Science in the Public Interest.
Jeff Cronin, a spokesman for the consumer group, said label changes might be more effective than recommendations alone. The group also supports a national recommendation on sugar limits, but the FDA does not plan to offer one.
And without more study, the U.S. Sugar Association won't support the World Health Organization's recommendation.
"We acknowledge the World Health Organization's efforts to help all nations address the issues of obesity and dental caries," the group said in a statement. "We are concerned that the draft guidelines' suggested limits — which would lump together sugar [sucrose] and other caloric sweeteners — rely heavily on insufficient scientific evidence."
But those who witness the effects of a poor diet say they'd like to see limits on sugar consumption and support the recommendations.
Dr. Norman Tinanoff, a pediatric dentist, said children who consume a lot of sugar tend to be fatter and shorter because they are not getting proper nutrition. They also can have cavities by the time they are 1, causing pain and necessitating sedation to fix with fillings or tooth extraction. Sometimes, a serious infection can arise.
It's the frequency of consumption that is most harmful to teeth, said Tinanoff, chief of the division of pediatric dentistry at the University of Maryland School of Dentistry. Bacteria sitting on teeth use the constant supply of sugar to produce acid that causes tooth decay.
"Some kids are eating all the time, cookies, candies, juices, sodas," he said. "Look at see how much sugar is in animal crackers and fruit juice. If you're walking around all day snacking like this you're going to get tooth decay."
Poor habits formed in youth lead to poor habits as adults. And Tinanoff said pain can make people less productive and the appearance of decay can make them less employable and sociable.
Dropping the harmful snacking and brushing twice a day with fluoridated toothpaste, even in young children, is now recommended. Tinanoff said he never brings up government guidelines, but talks about sugar consumption.
He asks parents why they think their kids have cavities and what they think they should do to prevent them "and they know the answers." He acknowledges he's not always successful.
Dr. Stephen Davis, an endocrinologist, has similar conversations with adults with diabetes. He said he doesn't demonize sugar but emphasizes the benefits of eating a balanced diet and exercising.
New guidelines can reinforce basic information people already know, but there are hurdles such as people's tastes and habits, said Davis, chairman of the department of medicine in the University of Maryland's School of Medicine.
And some information is misleading, such as small portion sizes listed on food labels, which the FDA does plan to update to make more realistic.
For now, he said the bulk of his patients do not eat right or exercise enough. Patients don't feel pressure to improve because diabetes, high blood pressure and high cholesterol don't necessarily have immediate and profound consequences.
"I don't think there is anything bad about sugar per se, but if we have too much sugar, or fat or even protein, there can be deleterious health effects," Davis said. "What we need to be doing is cutting down on our food intake and finding ways to have more physical activity. … It's tough when grabbing a soda and a bag of Doritos is the easiest and probably cheapest meal."