NEW YORK - Preschoolers who had less patience and worse self-control while waiting for treats in a classic behaviour study ended up weighing slightly more as adults, a new analysis shows.
Although the link between childhood patience and extra pounds in adulthood was "not particularly large," researchers said it might still help hint at which little kids are at risk of growing into overweight adults - and give their parents and teachers a chance to intervene.
"This is a skill or set of skills that really emerges through the preschool years," said Alison Miller, a developmental psychologist from the University of Michigan in Ann Arbor.
Self-control "is really developing for kids, and there are a lot of things that you can get in there and teach," she told Reuters Health.
Researchers said teaching patience and self-control to little kids may also have other long-term benefits, such as better grades and overall health.
"This is a struggle that all parents face," said Lori Francis, who has studied kids' self-regulation at Penn State University in University Park.
But, she told Reuters Health, "The idea that children have something to look forward to and there is this awesome reward if you learn how to be patient and wait... that has so much relevance for other things that kids will encounter in life."
Previous research has suggested self-control in preschoolers is tied to their weight as preteens. But for the new study, Tanya Schlam from the University of Wisconsin School of Medicine and Public Health in Madison and her colleagues wanted to look farther into the future.
They mailed health questionnaires to adults who had taken part in a delayed-gratification experiment in the late 1960s and early 1970s, when they were four years old.
For the test - which has now become standard in developmental psychology - kids are offered a treat like a marshmallow or cookie immediately or told they will get two marshmallows, for example, if they can wait 15 minutes.
The longer children are able to hold out for a bigger reward, the greater their self-control.
In the original marshmallow study, the average kid was able to wait about six and a half minutes for a treat. About a quarter had enough self-control to make it the full 15 minutes and get the extra snack.
By linking those test results to adults' reports of their own height and weight 30 years after the experiment, the researchers calculated that each extra minute four-year-olds were able to wait for marshmallows was tied to a 0.2-point decrease in their adult body mass index.
Body mass index, or BMI, is a measure of weight in relation to height. A difference of 0.2 points is equivalent to about one pound in most adults.
The majority of the 164 adults included in the final study were considered in the normal range for weight, according to findings published Thursday in The Journal of Pediatrics.
The study can't prove lack of self-control causes kids to become heavier adults, the researchers noted. They also didn't have information on other factors that could predispose people to gain more weight - such as whether or not their moms were also heavy.
Still, they think childhood self-control and patience play a role.
"Self-control is associated with so many outcomes important to society: weight... but also health, financial stability (and) likelihood of being convicted of a crime," Schlam told Reuters Health.
Francis, who wasn't part of the research team, said there could be basic differences between kids who are or aren't good at self-regulating - such as their environment growing up or their families' beliefs - that go on to influence eating and weight.
"The big question mark is explaining why this relationship exists," she said.
Of course, the typical four-year-old isn't exactly known as the model of patience and self-control. But Schlam said meditation, yoga, martial arts and mindfulness can all promote greater self-control, even in young people.
Miller, who also wasn't involved in the new study, said simply talking through self-regulation with kids - like validating their feelings that yes, it's really hard to wait - can help build basic patience skills. So can encouraging kids to distract themselves by thinking about something else in situations that require waiting.