Moms, when it comes to your child’s weight, you matter.

According to a new study in the British Medical Journal, children of mothers who had more healthful lifestyles had a 75 percent less chance of becoming overweight than the children whose mothers did not.

Those mothers had a body mass index of 18.5 to 24.9, engaged in at least 150 minutes a week of moderate to vigorous physical activity, did not smoke and consumed alcohol in moderation.

The study looked at more than 24,000 children of more than 16,000 nurses enrolled in the Nurses’ Health Study II in the 1990s. The researchers specifically looked at children who were not obese before age 9, then weighed them when they were 14.

The big takeaway: The researchers found that it wasn’t just about the children’s healthful lifestyle, it was about the mothers’, as well.

Dr. Kelly Thorstad, a pediatrician at St. David’s Children’s Hospital and Lone Star Pediatrics in Austin, Texas, said that what this study shows is it’s not just about genetics. While genetics are a factor, it’s also about lifestyle and creating an environment of healthful habits.

“I think children learn what they live,” she said. “Having parents that have a healthy lifestyle, that have a healthy weight, it will be good for the family.”

Some of the things she recommends families start doing:

No sugary drinks. (That includes juice.) The American Academy of Pediatrics recommended last year that babies younger than 1 should not have juice. Most other children should be limited to about ½ to 1 cup a day. Sodas have no nutritional value; skip them.

Have at least some family meals together to share healthful eating habits.

Avoid fried food. Instead of counting calories, worry about the amount of fat.

Focus on serving size. We have trouble remembering what a healthful serving is, especially at restaurants. “Look at your plate,” Thorstad said. “Cut everything in half, and that would be a normal serving size.”

Get protein throughout the day, especially at breakfast. Think boiled eggs, a protein bar without a lot of sugar, whole-grain cereal with milk or, better yet, yogurt with fruit and some whole-grain cereal on top.

Trade chips and cookies for fruits and vegetables as snacks after school and on weekends.

Drink water.

Control what you bring into the house. If you don’t bring in junk food, it’s not available for your kids to eat.

Control how much TV kids and parents are watching, and no TV in the bedrooms.

Thorstad said she encourages families to make small changes, such as going for a walk together after dinner.

“For children to make big changes, it’s a family thing,” she said.

She also encourages parents not to single out one child who is obese. Or to blame the mother, or the mother’s mother, or her mother before her.

“It’s not just the mother’s healthy lifestyle, it’s everyone in the family.”