Whole-grain foods help control women's weight
Last Updated: 2003-11-25 14:55:29 -0400 (Reuters Health)
By Amy Norton
NEW YORK (Reuters Health) - Middle-aged women who favor whole grains over white bread and other refined grains may put on fewer pounds as they age, a large study suggests.
Harvard researchers found that among 74,000 women, those who ate more fiber-rich grains--such as oatmeal and whole-grain breakfast cereals--gained less weight over time than women who got the least fiber in their diets.
In addition, women with the highest fiber intake were half as likely as those with the lowest intake to become obese over 12 years. In contrast, diets heavy in refined-grain products like white bread and pasta were linked to greater weight gain over time.
Simin Liu and colleagues at the Harvard School of Public Health in Boston report the findings in the November issue of the American Journal of Clinical Nutrition.
While carbohydrates have lately gotten a bad rap in the weight-loss realm, the new findings underscores the fact that not all carbs are alike, Liu told Reuters Health.
Research suggests that when it comes to weight control, whole grains such as oats, bran and brown rice have an advantage over highly processed, low-fiber grain products. For one, fiber-rich whole grains are more filling, and people who favor them over refined grains may take in fewer calories.
It's also thought, Liu explained, that while starchy refined grains cause a rapid increase in blood sugar, whole grains may create a slower, more sustained release of sugar into the blood -- which may have a beneficial effect on metabolism and fat storage.
Liu noted that whole grains also contain enzyme inhibitors that may get in the way of metabolic efficiency -- meaning the body is forced to burn extra calories just to digest and absorb whole-grain foods.
For their study, the researchers analyzed data from a large, long-running study of female nurses in the U.S. More than 74,000 women who were between the ages of 38 and 63 in 1984 periodically gave information on their diets and weight over the next 12 years. Other factors, such as exercise and alcohol intake, were also measured.
Liu's team found that at the start of the study, women who ate more whole grains tended to weigh less than those with diets heavier in refined grains. And over time, higher intake of fiber-rich grains was associated with less weight gain.
On average, women who ate the most high-fiber, whole-grain foods gained a few pounds less than those with the lowest fiber intake. They were also 49 percent less likely to become obese.
In the U.S., the researchers note, most of the grain products people consume are of the highly processed, low-fiber -- and often calorie-laden -- variety. The new findings, they say, emphasize the importance of distinguishing fiber-containing whole grains from refined ones.
SOURCE: American Journal of Clinical Nutrition, November 2003.
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