New moms who take walks instead of watching TV may lose those post-pregnancy pounds more easily, according to researchers.

In a study that followed 900 women for a year after childbirth, researchers found that those who regularly walked were less likely to retain their extra pregnancy weight. The same was true of women who watched TV less often and those who ate less trans fat -- artery-clogging fats found in a range of packaged snack foods and commercial baked goods.

What's more, the study found, the benefits of walking, limiting TV and shunning trans fats were cumulative -- suggesting that women who do all of these things may get back in pre-baby form more easily.

Dr. Emily Oken and colleagues at Harvard Medical School in Boston report the findings in the American Journal of Preventive Medicine.

"The childbearing years are a time of particular risk for weight gain in women," Oken said in a statement. "Modifiable behaviors in that early postpartum period -- such as diet, television viewing and walking -- can influence a woman's risk of retaining weight."

The study included 902 women who reported on their diet, exercise habits and TV viewing 6 months after giving birth. In general, Oken's team found, women who walked at least 30 minutes a day, watched TV less than 2 hours a day and ate relatively little trans fat were least likely to still have their pregnancy pounds one year after giving birth.

Compared with women who favored TV over walking, they were 77 percent less likely to retain 12 pounds or more.

The results are good news, according to Oken's team, because they suggest that busy new mothers need not work out for hours to shed their pregnancy pounds. A daily walk, whether on the treadmill or outside pushing a baby stroller, might be enough.

"Our findings aren't that you need to run marathons or be at the gym six hours a day," Oken said. "These behaviors are attainable for a lot of people, especially walking."