Families who express more warmth, group enjoyment and positive reinforcement at family meals have children with reduced risk of obesity, according to a new study.

“Past research has shown that having frequent family meals is protective against youth obesity, but we don’t know why this is the case,” said lead author Jerica M. Berge of the Department of Family Medicine and Community Health at the University of Minnesota in Minneapolis.

“The current study was designed to answer the ‘why’ question,” Berge told Reuters Health by email.

The study involved 120 children, ages six to 12, from families in the Minneapolis/St. Paul area who reported eating dinner as a family at least three times per week.

Family meals were video-recorded on iPads for an eight-day period.

They recorded types of foods, meal length, communication and interaction between parents and children and between siblings. Researchers also used parent and child surveys and interviews.

Three-quarters of the children were African American and half were overweight or obese.

Kids who were not overweight were more likely than overweight kids to have family meals last longer and to have a father or stepfather present. Overall, dinners lasted about 16 minutes, with an average of 18 minutes for healthy weight kids and 13.5 minutes for overweight kids.

“This finding may mean that when children have structure and more supervision at the meal they have more protection against overweight or obesity, (meaning) maybe a less chaotic meal environment and more chances to connect,” Berge said.

The kitchen was the most common location for dinners; 80 percent of healthy weight kids ate dinner with their families in a kitchen, compared to 55 percent of overweight kids. More families of overweight kids tended to eat in family rooms, offices or bedrooms.

Families with more warmth and nurturing, as rated by researchers observing the videos, were less likely to have overweight or obese children. Hostility, inconsistent discipline and permissive parental attitudes were associated with increased likelihood of childhood obesity.

“This may mean that in households where children are not overweight or obese there are more positive interactions at the family meal, which provides a sense of security, regularity and predictability which may help children regulate their own daily lives better, including self-regulating their eating behaviors,” Berge said.

Families who communicated more about food were less likely to have overweight or obese children, according to the results published in Pediatrics.

These findings only identify associations between meal habits and childhood obesity, and do not prove that mealtime dynamics cause obesity, Berge said, but there are some known healthy strategies parents can employ at the dinner table.

“It is important for families to try and promote a positive atmosphere during family meals,” she said. “For example, don’t use the family meal as a time to lecture children about their homework. Instead, take time to connect with each other such as asking each family member to talk about a ‘high’ or ‘low’ from their day to promote connectivity among family members.”

Another childhood feeding and obesity study, published in the same issue of Pediatrics, found that among same-gender twin pairs, mothers tend to be more restrictive when feeding the child with the higher body mass index (BMI), a measure of weight to height.

Researchers studied 64 pairs of twins ages four to seven, measuring their BMI, body fat percentage and waist circumference. Mothers reported their feeding styles toward each twin in a questionnaire, which assessed restricting food items, pressuring a child to eat and monitoring the child’s eating.

Observing twins helps to partially rule out the possibility that heavier children are genetically predisposed to have poorer eating self-regulation, or that they were shaped by their environment, since twins have the same genes and environment, said senior author Myles S. Faith from the University of North Carolina at Chapel Hill.

His results suggest that restrictive feeding may influence weight gain.

“First, foods that are withheld might become more desired or sought after – sort of like ‘forbidden fruit’,” Faith said in an email. “When children eventually do get access, they might chose these less healthy foods and overeat because they have that chance.”

“Second, restrictive feeding might disrupt children’s ‘satiety responsiveness’ – which is the ability to recognize when we’re full,” he said. “So, restrictive feeding may impede children learning this skill.”

Both new studies indicate that parental choices may help determine a child’s relationship with food and childhood weight gain.