March 24, 2011 -- Researchers taking nutritional snapshots of the population around a major metropolitan area for more than 30 years say they’ve noticed something interesting: as consumption of added sugars has increased, so too, have body weights.
Researchers parsing the myriad reasons for America’s collective growing girth have looked at the contributions of total calories and fat, experts say, but less is known about what role added sugars might play.
Added sugars are sugars in foods that aren’t naturally occurring. They’re mixed in as sugar or syrups during processing or preparation.
The sugar in fruit, fructose, for example, wouldn’t count as an added sugar. But the high-fructose corn syrup that’s added to some kinds of fruit cocktail would fall into that category. So would sugars added to sweeten yogurt, soft drinks, and processed snacks and desserts like cookies, cakes, and pies.
“We’re looking at trends,” says study researcher Lyn M. Steffen, PhD, MPH, an epidemiologist at the University of Minnesota School of Public Health. “We looked at them in women and men, and in both men and women, added sugar intake increased since 1980.”
“At the same time, BMI [body mass index] has also increased,” Steffen tells WebMD. Though the study isn’t designed to prove that one is causing the other, the closely parallel trends over 27 years of data collection may point to the need for closer investigation. “It looks suspicious,” she says.
An industry group that represents sugar producers says the evidence of a connection is lacking.
“A single study, performed by AHA [American Heart Association] or any other group, is inconclusive and needs further investigation,” says Andrew Briscoe, president and CEO of the Sugar Association. “When a major review occurs, the results always come back the same -- there is no scientific evidence to support a need to set an intake level for sugar.”
“It is necessary for consumers to understand the importance of practicing moderate consumption of all foods and beverages while maintaining a healthy lifestyle” Briscoe says. “Focusing on any one food takes away from the most important and more tangible goal of caloric balance.”
Looking at Added Sugars
Every five years since 1980, researchers have surveyed about 5,000 people around the Minneapolis-St. Paul, Minn. area, asking questions about what they ate within the last 24 hours. They also collected information about body weight, age, socioeconomic status, and lifestyle.
Researchers ran the answers through a software program that has compiled nutritional analysis information on hundreds of thousands of food products. By doing that, they were able to tell how much sugar people ate was added or naturally occurring.
Over 27 years since 1980, consumption of added sugars increased for all ages and both sexes.
In the latest survey, which was conducted from 2007 to 2009, for example, men were getting about 15% of their total daily calories from added sugars, nearly 40% more than was reported in the study’s first survey, which ran from 1980 to 1982.
Among women, added sugar intake rose from about 10% to about 13% over that same time period.
When researchers organized their results by age, they saw that younger adults reported eating more sugar than older adults.
At the same time, BMIs climbed along with sugar consumption.
There was one bright spot, however: in the 2000 to 2002 survey, added sugar consumption appeared to level off in both men and women and actually decreased a bit over the next seven to nine years. The BMIs of women also went down.
“I think women do pay more attention to their diet, and I think women are also paying attention to the messages of overweight and obesity,” Steffen says.
Watching Extra Sugar
The American Heart Association recommends eating no more than 5% of total calories from sugar. In a 2,000-calorie a day diet, for example, that’s about 100 calories of extra sugar, or about 24 grams, which is how sugar is listed on nutrition labels.
“It’s difficult because the label lists total sugars. The label doesn’t list added sugar,” says Rachel K. Johnson, RD, PhD, a professor of nutrition at the University of Vermont who has studied added sugars, but was not involved in the current research.
“So a good rule of thumb is, if there’s no milk or dairy products, which would have the sugar lactose, or no fruit, which would have the sugar fructose, the total sugars is a good indication of the amount of added sugars,” says. “If you have something like a flavored yogurt or a cereal with dried fruit in it, it’s a little more difficult.”
One way to figure out how much sugar has been added, she suggests, with a product like yogurt is to try to find a plain product to compare.
“Take a plain, unsweetened yogurt, if you can find one of the same brand, and compare the amount of sugars in that and compare the amount in the sweetened yogurt you’re looking at and the difference will tell you what’s been added,” she says.