What Happens When You Let Babies Feed Themselves?

I remember the first time my daughter discovered her hand. The look of amazement on her face was priceless. It wasn’t long before she was putting that discovery to use, trying to put everything she could find into her mouth.

Babies want to feed themselves. It sometimes feels as if parents spend more time trying to stop them than encouraging them. Over the last few years, however, some people have begun to ask if we are doing the right thing.

Baby-led weaning is an approach to feeding that encourages infants to take control of their eating. It’s based on the premise that infants might be better self-regulators of their food consumption.

It has even been thought that baby-led weaning might lead to reductions in obesity. While babies have been spoon-fed for a long time, the explosion of commercial foods for them might be making it too easy to overfeed them, an idea that the results from a cohort study in 2015 seemed to hint at.

Those weaned in a baby-led approach seemed to be more responsive to being sated and were less likely to be overweight. A case-control study from 2012 also argued that baby-led weaning was associated with a lower body mass index (B.M.I). Such trials cannot establish causality, however, and may be confounded in unmeasured ways.

A recent randomized controlled trial accomplished what previous work could not. Pregnant women in New Zealand were recruited before they gave birth and randomly assigned to one of two groups.

Both got standard midwifery and child care. But one group received eight more contacts, from pregnancy to the newborn’s ninth month. Five of these were with a lactation consultant, who encouraged the mothers to prolong breast-feeding and delay the introduction of solid foods until 6 months of age. The three other contacts were with research staffers who encouraged parents to read hunger and fullness cues from their infants and provide their babies (starting at 6 months) with foods that were high in energy and iron — easy to grab but hard to choke on.

The parents also received recipe books, food ideas, safety information and other pretested resources designed for the study.

The researchers were thorough. They frequently tested parents’ adherence to the baby-led approach throughout the second half of the first year of life, with outcomes collected by researchers who did not know which group participants had been assigned to. Before randomization, most of the mothers were planning to spoon-feed their babies, so this was a new way of thinking.

The results were disappointing. The study found no significant differences in the children’s body mass indexes at 12 or 24 months. Even when researchers restricted the analyses to the most adherent subjects, there were no significant differences over all in B.M.I.

The good news is that babies ate on their own: Parents can be reassured that coaxing their infants to eat more is not the only thing keeping them from malnutrition. The bad news is that more than 10 percent of the infants in the intervention group were overweight by 2 years of age. One of the most significant predictors of being overweight as an adult is being overweight as a child.

The best method of feeding babies has long been a subject of debate. An article published in 1948 in the same journal as this study, JAMA Pediatrics, reviewed the “literature on the so-called self-demand schedule of infant feeding” for prematurely born infants after they were discharged from the hospital. It noted that there was an increasing trend (in the 1940s!) toward allowing infants to regulate their own feeding. It noted the cyclical swings in thought between rigid regimentation of feedings and allowing too much freedom in a self-demand schedule.

It appears that some things have not changed.

The concerns expressed in the 1940s were very different from those of today, however. Then, people were focused on making sure babies got enough nutrition to grow and develop properly. Now, we are more worried about overconsumption and obesity.

It’s not clear whether humans are programmed to maintain a healthy weight on their own. Animals in the wild are subject to outside forces — the need to forage or kill, to compete, and to prepare for future shortages. Domesticated animals’ eating is regulated by us. Anyone who has owned a pet knows not to leave them alone with an open food supply, unless you want all that food to be gone.

This study supports the idea that, left to their own devices and supplied with more than enough food, babies will overeat. We still need to intervene. Nonetheless, there might be merit to giving infants more control over their eating: This study found that baby-led weaning resulted in children who were less fussy about what they ate and who seemed to enjoy their food more. Both of those things are good.

But if we want to find a larger solution to the issues of overweight American children and obesity, it seems we’re going to have to work harder. Babies aren’t going to solve the problem for us.