Families tend to eat more healthfully when they dine together regularly, but when kids enter the teen years, it may be hard for family dinners to thwart weight gain.

So say Elsie Taveras, MD, PhD, and colleagues in May's issue of Obesity Research.

Taveras isn't knocking family meals. She tells WebMD that families who eat dinner together have been shown to eat more vegetables and fruits than those who rarely or never dine together. They also tend eat less fried foods, soda, and items containing trans fats, says Taveras.

Her study also notes other researchers have found improved school and psychological performance in teens who eat dinner with their families, as well as fewer risky teen behaviors (such as using tobacco, alcohol, and marijuana).

That sounds like a recipe for all-around health. So why doesn't that translate to teen's weight?

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Pulling Up a Chair at the Family Table

At the study's start, 84 percent of the 14,000 boys and girls in the study said they ate dinner with their families on "most days" or "every day." They were 15 percent less likely to be overweight than those who said they only ate dinner with their families on "some days" or "never," says Taveras.

At that point, they were 9-14 years old. But three years later, it was a different story.

Family dinners are "known to have multiple health benefits and improve diet quality among kids" and didn't incline anyone toward weight problems, Taveras tells WebMD. However, she says "overweight protection didn't seem to be one of the benefits" as kids became teens.

"We weren't seeing the window where frequency of family dinners was protective," says Taveras.

Click here to read Web MD's "Why Do Low-Carb Diets Cause Weight Loss?"

About the Data

Data came from questionnaires completed by the kids on topics including their height, weight, and frequency of family meals.

The participants came from all 50 states and several U.S. territories. They were all children of nurses from a national nurses' health survey; more than 90 percent were white. So their results might differ from other children's, researchers write.

Blowing Off the Family Dinner?

By the study's end, the youths were 12-17 years old. They became less likely to eat dinner with their families as they got older, says Taveras.

Past studies have echoed that pattern, which may suggest changes in diet quality and "a need to look for ways to increase family dinners or to find alternative strategies to ensure diet quality among older adolescents," researchers write.

Teens have a lot of competing time demands, says Taveras. Other influences could also shape teens' eating and activity habits. Those influences include peers, schools, the media, marketing, and cultural norms.

In addition, teen's budding independence may make it easier for them to eat as they please (and suffer the weight consequences). Younger children are "really dependent on parents," says Taveras. "They have many shared eating behaviors [with their parents] and parents have a bigger influence on what children are eating in that age group."

Males were more likely to become overweight than females, study results showed.

Click here to read Web MD's "Secret Summer Diet Foods."

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Taveras, E. Obesity Research, May 2005; vol 13. Elsie Taveras, MD, MPH, Harvard Medical School.