ROBERT SIEGEL, host:
Before you wash down that Christmas cookie with your favorite soda, you might want to hear this. The good news first, several scientific papers now say that high-fructose corn syrup, that's the stuff sweetening your soda, isn't any worse for you than table sugar, at least when it comes to gaining weight. Now, here's the bad news from NPR's Allison Aubrey.
ALLISON AUBREY: We'll start with a question that's easy to answer. It's about this Olympian.
(Soundbite of Beijing Olympics)
Unidentified Man: Look at him go, the champion, Michael Phelps, the swimming power…
AUBREY: Does he need to worry about what type of sweetener or how much of it is in his pancakes?
Professor ELIZABETH PARKS (Nutrition, University of Texas Southwestern Medical Center, Dallas): However many calories he's eating per day, do you think it matters if he eats fructose or glucose?
AUBREY: Different kinds of sugars that will not make a difference in his case, says researcher Elizabeth Parks. She's professor of nutrition at the UT Southwestern Medical Center in Dallas. She says with the amount of training Phelps does, he's burning calories like mad.
Prof. PARKS: That's an extreme example, but he's able to use those for energy efficiently.
AUBREY: For all of us who don't have the muscle mass, metabolism, not to mention the youth of Michael Phelps, many of us are eating too many refined sugars. And nutritionists say they're not so good for us.
Prof. PARKS: This is the hard part is that what - at what level do we need to be careful about the intake of our sugars?
AUBREY: All the empty calories that come from sugars have no doubt helped expand waistlines globally, says researcher Barry Popkin of the University of North Carolina. He studies obesity around the world.
Dr. BARRY POPKIN (Researcher; Director; Interdisciplinary Obesity Center, University of North Carolina): A critical component of the American, the Mexican and many other countries' increase in overweight is caloric beverages.
AUBREY: Namely soft drinks, juices and sports drinks. Several years back, Popkin began to wonder if high-fructose corn syrup, which is used to sweeten many of these drinks, was of particular concern. He says before 1970, the world consumed a trivial amount of fructose, but when refined corn syrup became abundant and cheap, production exploded.
Dr. POPKIN: All of a sudden we're consuming dozens or hundreds of grams of this product, depending on the individual, and so you would have to raise questions.
AUBREY: Table sugar, which is made from sugar beets or cane, is a combination of two sugars, glucose and fructose. And so is high-fructose corn syrup. So from a molecular point of view, table sugar and high-fructose corn syrup look very similar. But they're metabolized differently.
Dr. POPKIN: Let's look at the effect on human health. That's what counts. It's not a question of, they look the same.
AUBREY: In the last few years, scientists have done a lot of research on how sugars work in the body, and they have some evidence that our bodies convert fructose to fat faster than we turn other sugars into fat. But remember, both table sugar and high-fructose corn syrup contain fructose. Barry Popkin says with all the new results, he's now convinced that both sweeteners, consumed in excess, are bad. One is no worse than the other in causing people to become overweight.
Dr. POPKIN: I would admit that we don't have an obesity effect, and I was the one who posed it before, and now we have a number of studies that show we don't have that.
AUBREY: But the case is not closed when it comes to other possible health effects. Richard Johnson is a researcher at the University of Colorado, and he's interested in how sugars are metabolized. Table sugar, he explains, enters the body with the glucose and fructose molecules bonded together. Enzymes in the gut have to separate them.
Dr. RICHARD JOHNSON (Researcher, University of Colorado): However, with high-fructose corn syrup, the two sugars are not bonded. And so there are different absorption characteristics. And that could - it's theoretical that it could lead to differences in manifestation of metabolic syndrome and other conditions. And we're studying that.
AUBREY: So if you followed the sugar chemistry lesson here, excellent. If not, here's the take-home message. If you look more like the average Joe than Michael Phelps, you might do well to cut back on sugary drinks and sweets of all kinds. Remember, New Year's Day isn't too far off. Allison Aubrey, NPR News, Washington.