After years of discussion, the U.S. Food and Drug Administration this week issued a recommendation that Americans limit consumption of added sugars in the foods they eat to the equivalent of about one soda per day.
The FDA is advising adults and children to limit their sugar intake to no more than 10 percent of their daily calories — about 50 grams or 12.5 teaspoons per day, roughly the amount found in an ordinary soft drink. But that benchmark applies only to sugars added to foods, not to those found naturally in items like fruit and milk.
The news, as first reported by The New York Times, comes amid an intense debate over what kind of diet will prevent weight gain and reduce the risk of disease. Public health experts and scientists have decried Americans’ ever-expanding waistlines — with more than one-third of all American adults now considered obese — and increased rates of obesity-related illnesses including Type 2 diabetes, hypertension and heart disease.
Prevailing consensus about what to eat and what to avoid has been mercurial for decades. In the 1970s Americans were advised to avoid saturated fats in order to prevent heart disease. But many compensated by eating more carbohydrates and sugar, and a bevy of “fat-free” foods — some laden with added sugar — began to flood the market.
Many scientists now believe that a low-fat diet doesn’t help people lose weight and keep it off in the long term. And epidemiologists and nutritionists say excessive consumption of added sugar is killing us, with obesity being only one indication of the problem.
Robert Lustig, an endocrinologist and professor at UCSF School of Medicine, explains that refined carbohydrates — those found in bread, pasta and French fries — are making Americans obese by priming the pancreas to produce insulin, which causes energy to be stored as fat.
And the added sugar people eat is making them sick, he says.
Naturally occurring sugars found in foods like fruits and some dairy products often come with fiber, which staves off hunger. But when the body digests food with added sugar, some of it is sent to the liver to be processed into energy. Because the liver can only handle so much sugar, it has to convert excess into liver fat — and over time that can lead to a condition called metabolic syndrome, a gateway to insulin resistance and Type 2 diabetes as well as high blood pressure and heart disease.
“Normal-weight people get metabolic syndrome, too,” Lustig said. “It’s not the obesity that causes it. Sugar causes that.”
The FDA has also said it wants food labels to differentiate between added sugars such as high-fructose corn syrup and the naturally occurring ones found in fruits. Most labels currently list only the total amount of sugar, and it’s up to consumers to wade through listed ingredients and decipher what they’re actually eating.
Industry groups including the Sugar Association have balked at the recommendations, saying the FDA hasn’t provided any scientific evidence of a “compelling public health reason” for changing the labels.
Obesity levels in the United States do appear to be leveling off. The Centers for Disease Control and Prevention’s National Center for Health Statistics on Thursday released new data on obesity rates from 2011 to 2014, and found that about 36.5 percent of adults and 17 percent of children were obese during those years, the latest for which data are available. That represents a statistically insignificant increase in obesity rates in adults among from in 2003-2004. Among children, the rate was unchanged from the previous decade.
Laura Schmidt, a professor of health policy at the University of California, San Francisco School of Medicine, said the flat levels of obesity are an encouraging sign that Americans are getting the message and changing their behavior, starting with their declining consumption of sugar-sweetened beverages.
Schmidt offered the example of tobacco, explaining that it took about a decade between the initial public health warnings that smoking caused lung cancer and the drop in lung cancer rates, because it takes a number of years for symptoms to develop and for scientists to begin cataloguing those changes.
“I think we need to be patient and wait, and I think we need to stay on this topic until we see the decline in obesity outcomes and ultimately in diabetes rates,” Schmidt said, though she is still concerned that the decline in soda is being replaced by sugary sports and coffee drinks.
However, Schmidt also points out that among very young children, obesity rates are actually dropping — they’ve plummeted by more than 40 percent in the last decade —because the children are benefiting from new wisdom and haven’t spent half their lives eating poorly.
“What we really need to be concerned about is the big picture, getting our children off of this processed junk food,” Schmidt said. “It all goes back to eating a diet of processed foods.”