Overweight mothers who exercise daily a year after the birth of their first child are, on average, 12 pounds lighter than overweight mothers who rarely work out, reports a new study from Cornell nutritionists.
What sets the exercisers apart from the nonexercisers, the Cornell researches say, is their "can do" attitude toward exercise during pregnancy.
"A woman's intention during pregnancy to exercise after delivery, as well as her confidence in her ability to exercise frequently, were the strongest predictors as to whether women would exercise frequently and lose weight after giving birth," said Christine Olson, professor of nutritional sciences at Cornell.
The research was conducted by Olson and Pamela Hinton, a former postdoctoral research associate in the Division of Nutritional Sciences at Cornell who now is assistant professor of dietetics at the University of Missouri. It was published in the Journal of the American Dietetics Association (December 2001) and is described on the Cornell "Ask the Nutrition Expert" web page this month at www.cce.cornell.edu/food/.
The researchers also found that the more positive feelings a woman has about motherhood, the more likely she is to exercise frequently after giving birth. Women in the study who restricted their food intake after pregnancy were almost four pounds lighter one year after birth than women who did not. And women who were still breastfeeding a year after birth were almost three pounds lighter than women who were not, when other factors were controlled for statistically.
In a related study by the same authors, published in Maternal and Child Health Journal (March 2001), the nutritionists found that older and more educated women and women living in households with higher incomes were more likely to work out before they became pregnant. Exercising before pregnancy strongly predicted whether women would exercise during pregnancy. But a woman's belief in her ability to exercise regularly -- which researchers describe as exercise self-efficacy -- also was a strong predictor for working out during pregnancy.
The studies are based on a sample of 622 women at the Research Institute of Bassett Healthcare in Cooperstown, N.Y., from pre-pregnancy through one year after the birth of their first child.
Although pregnant women eat for two, gaining more pounds than guidelines recommend puts women at six times the risk for obesity by a child's first birthday. The extra pounds contribute to the growing epidemic of obesity in this country, boosting the risks of a number of diseases including diabetes, heart diseases and high blood pressure, Olson said.
Previously she reported that by one year after delivery, more than one-quarter of the women in the sample were still 10 or more pounds heavier than their early pregnancy weight. She reported that 38 percent of normal-weight women, 67 percent of moderately overweight women and 46 percent of obese women gained more than the recommended guidelines during pregnancy.
Current guidelines issued by the Institute of Medicine recommend 25 to 35 pounds of weight gain for normal-weight women, 15 pounds of weight gain for obese women and 28 to 40 pounds for underweight women.
"We need to do a better job in enhancing women's intentions to exercise and their exercise self-efficacy by stressing the favorable effects of regular exercise and reduced food intake after giving birth," Olson said. "These benefits include better appearance, mental and physical health and physical fitness. We also need to help new mothers overcome common barriers to exercise, which include bad weather, exercise safety, lack of transportation, child care and time and money."
Said Olson: "Regardless of how much weight a mother gains, frequent exercise, appropriate reductions in food intake and breastfeeding up to at least one year after birth all significantly help take off gestational weight gain, which is critical for women's health."
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