That's the bottom line in explaining why 66 percent of Americans are now overweight or obese, according to the Centers for Disease Control and Prevention. You gain weight when you eat more calories than are burned off.
Nutritionists and health advocates are focusing attention on high-fructose corn syrup, or HFCS, the sweetheart of the processed foods industry. It's used in a wide range of foods, from baked goods and jam to salad dressings and drinks. It's nearly ubiquitous in ketchup, soft drinks and barbecue sauce.
The criticisms of high-fructose corn syrup range from the fact that most of it is made from genetically modified corn, to the way it's hidden in foods that appear healthy, to scientific concerns over the way it affects appetite and blood triglyceride levels.
"Corn syrup is in everything; it's in crackers, in fruit juice and soda, and the reason for that is because it has become incredibly cheap," said Michelle Murphy Zive, a registered dietitian and executive director of the Network for a Healthy California at the University of California San Diego.
The Corn Refiners Association, a trade group representing companies that make high-fructose corn syrup, cites studies on its Web site, corn.org, showing that the sweetener is no worse than any other sugar.
Dr. Mike Roizen, a founder of RealAge, a company that teaches people how to adopt a healthier lifestyle, agreed.
"Any sugar in high quantities isn't good for you," he said. "We don't know any redeeming social value for the high dose of sugar you get with a straight carbonated soft drink."
Just one can of soda contains 10 teaspoons of sugar - the recommended daily sugar intake from all sources.
PLENTIFUL PRODUCT
Starchy field corn was first refined into the sweetener dextrose around the Civil War. Today corn products such as dextrose and maltose represent 55 percent of the sweetener market, according to the Corn Refiner's Association. The technology took a leap forward in the early 1970s when scientists figured out how to further process corn syrup to make it into a sweeter substance called high-fructose corn syrup.
That coincided with the start of unfettered subsidies for corn farmers, leading to what investigative food journalist Michael Pollan called a "plague of cheap corn" in his book "The Omnivore's Dilemma" (The Penguin Press). Processors such as Archer Daniels Midland and Cargill jumped at the chance to turn that cheap corn into a range of additives, such as high-fructose corn syrup.
It turns up in many soft and gooey foods such as Gerber Graduates Cereal Bars with apple filling, Smucker's Jam, Bubble Yum gum and Pepperidge Farm Puff Pastry.
"It's sweet and light, so you have to use less of it than sugar," said Dr. John La Puma, a nutrition expert who co-authored "Cooking the RealAge Way" with Roizen. "From a manufacturer's standpoint ... it's cheaper than cane or beet sugar."
Most of the corn turned into high-fructose corn syrup is genetically modified, said Andrew Kimbrell, executive director of the Center for Food Safety in Washington, D.C. The corn may be modified to tolerate the herbicide Roundup or to contain a natural soil bacterium called Bt (bacillus thuringiensis) that kills pests when they nibble on the corn plant.
"If you avoid processed food, you go a long way to avoiding GMO (genetically modified organism) foods," Kimbrell said. "And the good news is, you have a healthier diet because you don't need foods like high-fructose corn syrup anyway."
Unlike governments in Europe, Asia and Africa, the U.S. government doesn't require manufacturers to disclose that they're using genetically modified corn, soybeans, canola oil or cotton. In his book, "Your Right to Know" (Earth Aware Editions) Kimbrell detailed which foods are most likely to contain genetically modified ingredients and how to spot them in ingredient lists.
The Center for Science in the Public Interest, of CSPI, based in Washington, said it's plainly misleading that high-fructose corn syrup is described as a natural ingredient, when it's the result of a series of complex chemical manipulations.
"When you hear corn syrup, you think you squeeze corn and get syrup," CSPI spokesman Jeff Cronin said. "But it's not even close to being natural."
In January 2007, CSPI sued Kraft Foods over the words "all-natural" on Capri Sun packages. Kraft agreed to remove the term. It has been replaced by "no artificial ingredients." There are many other products with high-fructose corn syrup that are labeled as "natural"; the Food and Drug Administration doesn't have criteria for using the word.
Other companies are hoping to attract buyers by noting on the labels that their product doesn't contain high-fructose corn syrup. Both Juicy Juice and Crayons - a colorful new line of fruit-juice drinks - list the lack of the sweetener on their labels. (But a 12-ounce bottle of strawberry-kiwi Crayons has 7 teaspoons of sugar; 8 ounces of Juicy Juice contain nearly the same amount.)
OBESITY ISSUE
The most contentious part of the debate on high-fructose corn syrup surrounds whether it behaves in the body the same as other sugars like glucose, the complex sugar found in a baked potato; sucrose, which is simple table sugar; and fructose, found in fruits and honey.
A 2001 study by researchers at the Children's Hospital of Boston and the Harvard School of Public Health found that adolescents' risk of obesity increased 1.6 times for every sweetened drink they drank over the daily average. The study followed 548 sixth- and seventh-graders for 21 months.
In August 2007, Archer Daniels Midland released its own study - based on self-reported data - stating that drinking soda does not play a role in obesity. That study concluded that eating high-fat foods or watching television played a greater role in obesity risk.
Dr. Peter Havel, a professor in the department of nutrition at the University of California Davis, has spent a decade studying diabetes and obesity and how foods affect metabolism.
When we're hungry, one of the hormones the body produces is grehlin. Once we eat, the amount of grehlin in our bodies declines. During a study, Havel's team found that the level of grehlin declined more quickly when subjects ate glucose compared with when they ate fructose, said Kimber Stanhope, his research associate.
But the researchers saw something more interesting during a 10-week study of adults ages 43 to 70 who were fed a diet that included either three glucose drinks or three drinks sweetened with fructose daily.
Both groups gained weight, but the ones who drank fructose gained it in their midsection. The fructose drinkers also had higher levels of fat and bad LDL cholesterol in their blood.
"When you provide a high-fructose diet to the liver, it tends to process much of that fructose into lipids (fats), which is why you get high triglyceride levels," Stanhope said. "The triglyceride response to fructose is likely to turn out to be the greater health concern."
The preliminary findings from the $1.25 million study, funded by the National Institutes of Health, were reported at the American Diabetes Association conference in June. Further studies are in the works.
CONSUMER AWARENESS
With the line between healthy and not-so-healthy foods becoming blurred, it's important for consumers to know what they're putting in their mouths.
"People don't realize that low-fat salad dressings are high in high-fructose corn syrup," Roizen said. "You've got to read the labels."
In the book "You on a Diet," co-written with Dr. Mehmet Oz, Roizen advises going through the kitchen and trashing any product with high-fructose corn syrup among the first five ingredients, meaning that product has a high percentage of sugar.
Even small changes can make a difference. As director of UCSD's Cancer Prevention and Control Program, Vicky Newman designs strategies to motivate people to eat more healthfully. When researchers taught women to scan labels for hidden sugars and cut down on sugars and white flour during a recent study, the women all lost weight - without any more exercise.
Zive, of UCSD, recommended watching sugar intake from all sources, including raw sugar, honey and even juices that say they're 100 percent apple or grape juice - both of which are high in sugar.
"Don't drink fruit juice," Zive said. "Drink water and eat fruit. An apple has vitamins and minerals and fiber that fruit juice does not have."
Parents also need to keep in mind that the portion sizes listed on many foods are for adults, not children. Zive recommended visiting www.mypyramid.gov to see the recommended daily calorie intake for men and women of various ages, and a breakdown of the empty or discretionary calories in snacks.
Watching portions and sugar intake are two of the recommendations from the Childhood Obesity Initiative, an effort to get many sectors of the community, to work together to reduce childhood obesity and diabetes rates in San Diego County.
"We're saying, let's make a shift so it's easier for parents to go to a store and find healthy alternatives," Zive said. "With balance and moderation, we can have our cake and eat it, too."
