In an opinion piece called “The Toxic ( 毒性的) Truth About Sugar” published Feb.1 in Nature, Robert
Lustig, Laura Schmidt and Claire Brindis argue that it’s wrong to consider sugar just “empty calories.” They
write: “There is nothing empty about these calories. A growing body of scientific evidence is showing that
fructose (果糖) can trigger processes that lead to liver toxicity and a host of other chronic diseases. A little is not a
problem, but a lot kills — slowly.”
Almost everyone’s heard of — or personally experienced — the well-known sugar high, so perhaps the
comparison between sugar and alcohol or tobacco shouldn’t come as a surprise. But it’s doubtful that Americans
will look favorably upon regulating their favorite vice. We’re a nation that’s sweet on sugar: the average U.S.
adult downs 22 teaspoons of sugar a day, according to the American Heart Association, and surveys have found
that teens swallow 34 teaspoons.
To counter our consumption, the authors advocate taxing sugary foods and controlling sales to kids under
17. Already, 17% of U.S. children and teens are obese (肥胖), and across the world the sugar intake (摄入) has
increased three times in the past 50 years. The increase has helped create a global obesity plague that contributes
to 35 million annual deaths worldwide from noninfectious diseases including cancer, heart disease and diabetes.
Linda Matzigkeit, a senior vice president at Children’s Healthcare, said “We have to do something about this or
our country is in danger. It’s not good if your state has the second-highest obesity rate. Obese children turn into
obese adults.”
“There are good calories and bad calories, just as there are good fats and bad fats, good amino acids (氨基
酸) and bad amino acids,” Lustig, director of the Weight Assessment for Teen and Child Health program at UCSF,
said in a statement. “But sugar is toxic beyond its calories.”
The food industry tries to imply that “a calorie is a calorie is a calorie,” says Kelly Brownell, director of the
Rudd Center for Food Policy and Obesity at Yale University. “But this and other research suggests there is
something different about sugar,” says Brownell.
The UCSF report emphasizes the metabolic (新陈代谢) effects of sugar. Excess sugar can alter metabolism,
raise blood pressure, affect the signaling of hormones and damage the liver — outcomes that sound suspiciously
similar to what can happen after a person drinks too much alcohol. Schmidt, co-chair of UCSF’s Community
Engagement and Health Policy program, noted on CNN: “When you think about it, this actually makes a lot of
sense. Alcohol, after all, is simply made from sugar. Where does vodka come from? Sugar.”
But there are also other areas of impact that researchers have investigated: the effect of sugar on the brain
and how liquid calories are interpreted differently by the body than solids. Research has suggested that sugar
activates the same reward pathways in the brain as traditional drugs of abuse like morphine or heroin. No one is
claiming the effect of sugar is quite that strong, but, says Brownell, “it helps confirm what people tell you
sometimes, that they hunger for sugar and have withdrawal symptoms when they stop eating it.”
There’s also something particularly tricky about sugary drinks. “When calories come in liquids, the body
doesn’t feel as full,” says Brownell. “People are getting more of their calories than ever before from sugared
drinks.”
Other countries, including France, Greece and Denmark, impose soda taxes, and the concept is being
considered in at least 20 U.S. cities and states. Last summer, Philadelphia came close to passing a 2-cents-per-
ounce soda tax. The Rudd Center has been a strong advocate of a more modest 1-cent-per-punce tax. But at least
one study, from 2010, has raised doubts that soda taxes would result in significant weight loss: apparently people
who are determined to eat — and drink — unhealthily will find ways to do it. Teens — no surprise — are good at
finding ways to get the things they can’t have, so state policies banning all sugar-sweetened drinks from public
schools and providing only water, milk or 100% fruit juices haven’t had the intended effect of steering kids away
from drinking sugared drinks: the average teen consumes about 300 calories per day — that’s nearly 15% of his
daily calories — in sweetened drinks, and the food and drink industry is only too happy to feed this need.
Ultimately, regulating sugar will prove particularly tricky because it goes beyond health concerns; sugar, for