For the millions of Americans trying to lose weight, the familiar message has been to eat less fat and more carbohydrates. But experts say this shift to pasta and potatoes has potential problems.
ABC's World News Tonight medical correspondent John McKenzie reports that experts believe many Americans have gone too far in the switch to carbohydrates.
According to Lisa Tartamella Kimmel, registered dietician at Yale-New Haven Hospital, when it comes to eating right, many people may have been receiving mixed messages.
"The intention of the 'low fat, high carbohydrate' message was to encourage Americans to reduce their excessive fat intake, particularly saturated fat, and consume more carbohydrates from fruits, vegetables and whole grains," Kimmel says. "The message was not 'do not eat fat' or 'eat all of the fat-free and low-fat carbohydrates that you want.' Somehow in the whole process, the message of moderation was ignored."
Too Many Carbs?
Experts agree that carbohydrates themselves aren't necessarily a bad thing, just that Americans need to know the problems associated with eating too many of them.
"There is nothing wrong with carbohydrates, they're a major staple in the diet," says Dr. Robert Eckel, chairman, American Heart Association's nutrition committee.
"The issue here is kind of misinterpreted. People gain weight because they eat too many calories, not too many carbohydrates. So the bottom line is, gaining weight is not attributed to carbos or fat," Eckel adds.
But Dr. Walter Willett, chairman of the department of nutrition at Harvard School of Public Health, explains it's not only the amount of carbohydrates you eat, it's also the type that's important.
"What's become quite clear is that not all carbohydrates are the same," says Willet. "When we eat a baked potato, we get a more rapid spike in blood sugar than we do even after eating pure table sugar."
Willett believes that eating too many carbs that are refined or in the form of sugar can make it difficult to control weight because they're quickly absorbed, sending blood sugar levels soaring, followed by high surges of insulin.
"After two or three hours, the large amounts of insulin bring the blood sugar levels crashing down, sometimes even below normal levels," says Willett. "At this point, people feel strong urges to look for snacks well before the next meal. Over many years, these powerful surges of insulin exhaust the pancreas to the point where diabetes can develop." Willett points to fat-free breakfasts, such as a bagel and jam, as foods that can cause this type of problem.
Eckel disagrees, and points out that "literature suggests higher-fat diets can cause more insulin resistance."
Elizabeth Ward, registered dietician and former spokesperson of the American Dietetic Association, says that when you eliminate fat from your diet, you need more carbohydrates to fill the void. But some carbs may be better for you than others.
"Clearly, whole grains are the good guys. We do eat too many refined carbs such as white bread," adds Ward. "However, I refrain from slamming single foods, including potatoes. Here we are trying to get Americans to include vegetables, and we're telling them certain ones are bad. White bread and refined bagels are not the best choices every day, that's for sure. However, every once in a while won't kill you."
Good Fat, Bad Fat