Gaining weight is pretty easy; even a child can do it. Overweight and obesity in childhood are linked to significant health problems as kids age. A new Harvard Medical School study suggests that preventing it, and even helping kids lose weight, may also be pretty simple.

The researchers tested a simple at-home intervention to help at-risk families with their kids’ weight, and other habits. The study involved 121 families with children from two to five years old.

Half of the families took part in the program, called “Healthy Habits, Happy Homes,” in which they were urged to make a few lifestyle changes: Make sure their kids got enough sleep, have family meals together, limit the amount of television the kids watched, and act as role models and set limits for the kids.

Relatively simple, no-cost changes in routines within the home can help children maintain or achieve a healthful weight.

The other half of the families served as controls. They received monthly packages that included information about child development, but were not part of the in-home program.

Families in the experimental program were visited at home to help keep them on track. They also received frequent text messages, phone calls, and newsletters.

Children in the Healthy Habits program were also given toys, stickers, and books to encourage healthy habits. The families were not told that the program was designed to help kids with weight. Families in both groups had home visits at the beginning and end of the study’s six months, during which the researchers measured the kids’ height and weight, and asked them a number of questions related to lifestyle.

At the end of the six months the kids in the intervention group had lost 0.18 from their body mass index (BMI) measures, while kids in the control group had gained 0.21 in BMI. It's important to keep in mind that slowing weight gain as children are growing is a form of weight-loss.

“The Healthy Habits, Happy Homes intervention was able to slow weight gain relative to height increase in these children which is important because — as our earlier research has shown — rapid weight gain in these early years can lead to higher rates of obesity later in life,” study author Elsie Taveras said in a statement.

The kids in the intervention group also slept an average of 45 minutes per night longer than those in the control group. Since sleep and weight are interconnected this also contributed to the reduction in body mass.

Average television time dropped by an hour per day on the weekends, while the control group increased their weekend viewing (there was a similar pattern in weekday watching, but it was not as strong).

“Our findings demonstrate that relatively simple, no-cost changes in routines within the home can help children maintain or achieve a healthful weight,” said Taveras.

Studies are currently under way to see how long these effects last after the intervention is over, and how much of a “dose” of the intervention is needed — the number of in-home visits or phone calls — in the first place.

The crucial point of any intervention or lifestyle change is to begin it early, before bad habits become more ingrained and are harder to reverse. “Interventions such as ours can be one way of keeping young children off an obesity trajectory that would be hard to alter by the time they enter middle school,” says Taveras.

Lifestyle choices — sedentary kids consuming too many empty calories — have been a source of the problem; they are also part of the solution. The simple things we do can make a lot of difference in the health of our kids and ourselves.

The study is published in JAMA Pediatrics.