Withholding certain foods from children may lead to weight gain, study finds

Oct. 22, 2014

Many parents believe the best way to prevent their children from becoming obese is to limit their intake of calories or withhold particular types of foods altogether. However, a new study from The University of North Carolina at Chapel Hill challenges this belief. The study supports growing evidence that, in the long term, these tactics actually may produce the opposite effect.

Dr. Myles Faith

“Our results showed that limiting access to certain foods – ‘restrictive feeding,’ as we call it – was related to a higher weight status in children,” said Myles S. Faith, PhD, the study’s senior investigator and associate professor of nutrition at UNC’s Gillings School of Global Public Health.

Faith said that highly restrictive or controlling feeding practices, while well-intentioned, paradoxically may increase a child’s consumption of the withheld food.

“Foods that are withheld might become more desired or sought after, a kind of ‘forbidden fruit,’” Faith said. “When children eventually do get access to these foods, perhaps outside of the home, they might overeat because they finally have that opportunity.”

Faith said that restrictive feeding might disrupt children’s ‘satiety responsiveness’ (the ability to recognize when we’re full) and even may impede children’s learning of this skill.

“At the same time,” he said, “parents may restrict in response to their children’s weight status. If a child is heavier, the parent may attempt to limit food access, so there is a bit of a ‘chicken-and-egg’ challenge in trying to understand which comes first – heavier body weight or restrictive feeding.”

The study, “Differential Maternal Feeding Practices, Eating Self-Regulation and Adiposity in Young Twins,” appears in the November issue of the journal Pediatrics.

Researchers performed the study by focusing on 64 pairs of same-sex identical twins, of diverse race and ethnicity. Of the children who were study subjects, 52 percent were white, 17 percent were African-American, 15 percent were Hispanic, 3 percent were Asian and 13 percent were “other” or “mixed.” Of the mothers, 59 percent were college-educated, 75 percent were married and 58 percent were currently employed.

Focusing on identical twins allowed the researchers to take a new approach toward studying associations between parenting, regulating children’s eating and children’s body weight. The novel approach partially controls for child genetic influences, which has not been done in prior studies. This is an important consideration, as restricting children’s eating would not be effective if their heaviness was the result of genetic causes.

Because identical twins have the same genes, and fraternal twins share, on average, half their genes, genetically-caused obesity is less likely to be a mitigating factor in the study. Conducting the study with this sample also ruled out aspects of the home environment that are identically shared by twins, such as foods available in the cupboards or refrigerator.

“We found in this particular study that mothers of twins do feed their children differently,” Faith said. “This is interesting because studies with non-twin siblings find that parents often treat their children differently. Our findings show that this differentiation occurs even among twins.”

What kind of differentiation? Mothers employed more restrictive feeding practices toward the heavier than the lighter twin. Additionally, greater pressure to eat was put on the lighter than the heavier twin, with mothers exhorting them to eat more. Previous studies have shown that this kind of pressure can lead to disrupted eating patterns and possibly contribute to childhood obesity.

“These are the same kinds of practices and pressures seen in parents of non-twin children,” Faith said. “With the same types of patterns appearing among mothers of twins, we need to take that next step and determine whether there is a direct cause-and-effect between these parenting behaviors and childhood – or even long-term – obesity. Researchers also need to examine novel alternatives to restrictive feeding in childhood obesity treatment and prevention, possibly investigating strategies giving children greater choice.”

Gina L. Tripicchio, MS, MSEd, and Cassandra Johnson, MSPH, nutrition doctoral students at the Gillings School, are co-authors of the study. Other co-authors include Kathleen L. Keller, PhD, in the departments of nutritional sciences and food science at Pennsylvania State University; Angelo Pietrobelli, MD, of the pediatric unit at Verona University Medical School (Italy) and Pennington Biomedical Research Center in Baton Rouge, La.; and Moonseong Heo, PhD, in the department of epidemiology and population health at Albert Einstein College of Medicine (Bronx, N.Y.).